Having rectified many ‘chuffing’ injectors and dealt with the famed ‘black-death’ on many sprinter engines and its close derivatives used across the complete range of Mercedes Diesel vehicles, I can honestly say that the hold down mechanism used to secure the injector in the head is definitely the engines number one Achilles heel. I am afraid that a single 6mm cap head pin used on one edge of a single steel injector clamp, tapped into an aluminium head is just engineering madness from a commercial maintenance point of view. Now that’s out of the way – rant over – how do we best deal with this problem and get that vehicle back on the road.
You will be reading this if you have begun to hear the release of combustion gas from around the engine bay of your vehicle (chuffing) or you may have discovered a black shiny coal like deposit building around one or several injectors (black-death) in addition to lacklustre performance and increased fuel usage. Before we carry on, it is of great importance to bring to your attention that we are dealing with a direct injection fuel system with operating pressures around 23,000 psi or 1600 bar! This fact is to be remembered when working on a running system, when either fault finding or during rectification – Serious injury may result if you do not respect the obvious dangers involved. If you cannot identify the dangers of working with very highly pressurised fuel systems you would probably be better to entrust the work to a specialist.
If the ‘chuffing’ has been noticed early on, none or very few ‘black death’ carbon deposits will be seen, just wetness from ejected diesel resulting from the failing combustion process forced up around the leaking injector out to atmosphere on the cylinder head. If carbon deposits are present then they will have to be completely cleared and chipped away with a blunt screwdriver/scraper and vacuumed away as you go.
Injector Black Death Mercedes Sprinter
Because of the close proximity of other injectors it may be difficult to identify exactly which one is the culprit. If the leaking injector is not obvious, then clean down the area with Gunk or other degreaser and dry off the area (engine off of course) completely. Using 2 inch strips of old brown paper cut from the envelopes of your unpaid bills (joke) make hollow tubes and wrap them around the injectors, fastening the ends together with a paper clip. Do this for all suspect injectors. Start the engine and watch for the darkening/spotting of the brown paper with diesel spray, this will indicate quite clearly where the problem lies.
Once identified the work can begin – Run the engine until nice and warm then turn it off and remove the keys. Remove the turbo supply hose to the inlet manifold and split the composite intake manifold by removing the pins that secure it to the lower section. Remove the two pins that are also fastened to engine brackets at the rear and front of the head by the fuel filter. Lift off the manifold and stuff the remaining open ports with paper/cloth to prevent bits dropping inside. Check the gasket at the back plate/cover of the upper section of the inlet manifold as this is prone to squeezing out causing turbo boost leak and is this a good time to take a look/plan to rectify.
Remove completely the steel fuel supply pipe from between the leaking injector and the fuel rail along with its injector electrical connector; tie this cable out of the way of the work area. Remove the long single 6mm torx bolt that secures the injector clamp and place it safely to one side with the clamp itself. Inspect the threaded portion of the 6mm bolt if it is damaged or showing heavy signs of alloy material deposited on the threads then further action may be needed later on to rectify the threads in this failing all important tapped hole.
The next part of the procedure is ‘make or break’ for the DIY repair and is the point of no return so please take heed. Try to rotate the unclamped injector, if it moves freely by hand then great, if it won’t budge try a little more force – but not too much. If it’s seized then at this point re-assemble the engine and take it to a diesel specialist as damage to the injector or head can be very expensive indeed and botched repairs will easily exceed the cost of it being done by a professional in the first place – you have been advised. If the injector rotates, begin to pull it upwards whilst twisting the body, if it jams, twist it the other way and work it using some penetrant or WD40 in the area around where it enters the head. In some cases the injector lifts out instantly, in others it can take hours of wiggling and fiddling, don’t be tempted to use hammers or heavy tools to do this job as commonly expensive damage results. The image below shows damage to a rocker/cam cover caused by levering against it to extract a stubborn injector.
Damaged Sprinter Rocker Cover
Once the injector is out, clean it off and place it safely out of the way then recover the single copper washer from the hole in the head that forms a gas tight seal for the injector against the aluminium cylinder head. Use a torch to inspect the injector seat in the cylinder head, it will likely be blackened and carbonised, this needs to be cleaned off and in severe cases re-cut to present a perfect sealing surface. I have in the past had great success using a wooden dowel, rather like the ones used on a valve grinding hand tool. Using contact adhesive stick a square of medium abrasive paper to the end of a flush cut dowel, allow the glue to dry then trim round with scissors. Pop this tool down the hole and clean the seat as if you were grinding in a valve. Inspect it regularly and if there are slightly deeper grooves remaining keep going with new paper until clean and flat. Now the top tip, it will be necessary to purchase a new copper sealing washer. The best thing to do here is purchase a Honda part in preference to the genuine Mercedes Benz item. This washer is the standard CDI injector seal used on all modern Honda 2.2 litre diesel engines (More info on the Honda seal – here). I personally have had great success using the Honda part as they seem to be made from a superior material and appear more compressible thus making a better seal against any slight face imperfections.
Sprinter Injector Seal
If your 6mm torx clamp bolt came away cleanly and without damage, discard the old one and purchase a new item from Mercedes. This part is a stretch type bolt and once used must be replaced. The bolt hole has to be spotless and clean and have no debris or metal swarf at its base. Any solids in the hole will be compressed at the base of the drilling when the bolt is tightened and can cause cracking or worse – bursting through into the water jacket of the cylinder head (really easily done) so clean that hole with an air-line or blow gun until you are sure it’s clear.
Sprinter Diesel Injector
Replace the injector with its new copper sealing washer, using a slight smearing of high temperature ceramic grease on the body sides and position it correctly with regard the electrical connector, replace the clamp and clamp bolt, fit the new clamp bolt and torque it down to 7Nm then 90 degrees turn to finish – NO MORE.
While the actual MB recommended spec for tightening the hold down clamp bolt is 7Nm plus 90 degrees, plus 90 degrees – 7Nm plus 90 degrees will provide a safer torque to yield on a new bolt in an old head.
The Honda washers are ‘softer’ (unmeasured science, but you can tell) and I have always consciously never bothered with the extra and last 90 degrees crank. Never had any trouble.
Each 90 degree rotation past 7 Nm with a new clamp bolt and clean hole results in a further 0.3mm stretch bolt yield, so my view has always been – softer composition, less crush and a little less beads of sweat on the final swing of the wrench! (Those threads are a weakness) Correct spec by the book with thinner less malleable copper MB washers is 7Nm +90 +90.
The full factual reference write up is here, I always have agreed with the final conclusion that offers this advice and hence never added the increased stress of the final 90 degrees. Obviously the final choice of wether to use the factory torque spec or the modified spec is entirely your choice, but the tests carried out below are well worth a read before you make that decision.
Technical Reference Article:-
Tightening the fresh hold down bolt and seal ring will produce the same clamping force (defined by seal ring crush thickness) regardless of which of the 2 torque specs are used.
The desired residual bolt stress (to achieve essentially infinite cyclical fatigue life) is achieved by both specs but the 2X 90 spec does allow for less care and precision during the tightening procedure. Torque spec #1 (62in/lbs +90) is certainly less risky if contamination may be lurking at the bottom of the very deep blind bolt hole. I suspect it is also somewhat less risky if the aluminum threads are not in ‘as new’ condition.
“Here at the Global Sprinter Research Center I am always eager to investigate Sprinter related technical issues.
Group members have noticed that Mercedes Benz has a published torque spec for the injector hold down bolts that seemingly differs significantly from the long standing DC published specs as shown in DC workshop manuals as well as on the instruction sheets that DC at one time included with replacement injectors. The extended threaded shank length, 85.83mm long, 6.0mm dia., 8.8 grade, factory hold down bolt, hold down pawl and injector seal ring are identical part numbers for both the 5 cyl. and 6 cyl. engines.
Using my ‘test’ 647 Sprinter cylinder head, which is permanently mounted to one of my work benches, I have recently performed tests related to hold down bolt torque. This dedicated ‘test’ cyl head has been quite useful in my repair tooling fabrication.
As many of you know I have developed in-house tools and fixtures for removal of broken hold down bolts, repair to stronger than new stripped hold down threads, and various custom black death repair tools for my in-house use. This test head features my custom carbon steel hold down threads making it ideal for these hold down bolt torque experiments because data is not compromised by any aluminum thread deformation or failure.
After careful measuring of bolt length (before and after torquing) and injector seat seal thickness to 0.01mm tolerance, and using a calibrated Snap-on electronic 1/4 inch drive torque wrench set to display in/lbs and accurate to 0.1 in/lbs, I have the following observations to report:
TRIAL 1– A fresh, factory hold down bolt torqued to 62 in/lbs (approx 7 Nm) and then an additional 90 degrees, results in 0.08mm crush of a fresh factory seal ring.
The Sprinter’s copper seat seal ring features a double convex cross section and the clamping force induced ‘crush’ creates narrow sealing flats on each side of the ring.
Monitoring the bolt torque during the 90 degree rotation reveals a peak of 180-190 in/lbs before full 90 degrees is achieved and remains at this level all the way to 90 degrees. This peak/plateau signals bolt yield has occurred.
TRIAL 2– A new seal ring and a fresh, factory hold down bolt torqued to 62 in/lbs. (approx. 7Nm) and then an additional 90 degrees X2 (FULL 180 degrees), results in the same 0.08mm crush of the seal ring as well as a steady 180-190 in/lbs torque reading during angle tightening.
Being a stretch to yield, non-reuse, bolt it was not surprising to see permanent elongation. Elongation was approx. 0.30mm for each increment of 90 degrees of tightening rotation (after the 62 in/lb initial torque).
TRIAL 3-A fresh hold down bolt tightened to failure. The bolt tolerated several additional 90 degree sequences PAST the initial 62 in/lbs and 2×90 degrees.
It has previously been reported that fresh hold down bolts have failed when several group members had torqued to 62 in/lbs and then 180 degrees (mistaking 1/2 turn for 90 degrees). I now suspect this occurred because of bolt bottoming in the base of the blind bore. Bottoming can occur because of debris at bottom of the blind hole.
CONCLUSION:
Tightening the fresh hold down bolt and seal ring will produce the same clamping force (defined by seal ring crush thickness) regardless of which of the 2 torque specs are used. The desired residual bolt stress (to achieve essentially infinite cyclical fatigue life) is achieved by both specs but the 2X 90 spec does allow for less care and precision during the tightening procedure.
Torque spec #1 (62in/lbs +90) is certainly less risky if contamination may be lurking at the bottom of the very deep blind bolt hole. I suspect it is also somewhat less risky if the aluminum threads are not in ‘as new’ condition.
Be sure you test your cyl head’s bolt hole threads by using a wire brushed used hold down bolt with an indexing paint mark, turning in by hand while counting turns, to assure threads are clean and bore is unobstructed to full depth. This is especially critical when performing black death surgery.”
Information source provided with thanks by Andy Bittenbinder
If you had a problem with the thread you can use this type of kit or as a more desperate measure carefully tap out the hole to 8mm using a long series drill and tap, if you do this you will also have to drill out the clamp bracket to accept the new diameter bolt. When drilling/tapping take care to not descend deeper in the head than you need to and break into the water jacket. Sometimes you may find that the previous repairer has broken into the water jacket – add a small amount of silicon gasket compound to the last section of threads of the pin and tighten down in the normal way. This is not the best way to get out of trouble, but will at least enable you to complete the job. If you don’t do this and a bolt hole is broken through – you will leak water!!
Now your injector is back together, in the cylinder head and clamped down, reconnect the steel fuel supply hose and electrical connector and build up the inlet manifold and turbo pipework. Start and test the engine. The engine should fire after a couple of cranks as no fuel bleeding is necessary. All should now be well with the repair and you have carried out a major maintenance repair saving you hopefully quite a lump of cash.
More info dealing with the actual removal/installation of the injector and its seal – here
Good luck.
Thanks for an excellent, no-nonsense description. (I am a motoring journalist, so very critical of most of the utter tosh you see on the Internet in respect of problems such as this.) I first did this job four years ago – with all the usual dramas, having unknowingly let the ‘black death’ build up to epic proportions – and am now in the process of doing it again on the same vehicle. The information I was after was the tightening torque for the stretch injector bolts – having mislaid my notes from 2010 – and this you have provided, along with many other useful details. I wish I had seen this when I first needed to do the job! Best wishes, Chris
Hi Chris,
Glad you found the info useful, thanks also for the very kind words! If only I had more time to add more information, life has a habit of throwing obstacles in the way of that one – but I do enjoy keeping it rolling as and when I get the chance.
All the best
Steve
Hi just getting mine done by a guy who said he has been a mechanic for 20 years, he removed all 6 injectors on my sprinter 319 without damaging any of them….however while he was in the process of putting everything back together he realised that the engine would not spin 360% by hand…he had unknowingly dropped a piece of the black gunk into the combustion chamber. Now I am waiting for him to finish the job that has turned from a one week job to coming up to 3 weeks now. Decided to get the 2 heads machined and tidied up while they were off. BIG lesson here..MAKE SURE NOTHING gets loose and fall into that little hole.
Hi Bob,
Its a rather sad tale you tell, bad luck just sometimes befalls us all… but on the upside you have made a wise investment in working the head whilst you have the opportunity. This unscheduled maintenance should now hopefully give you many more miles of trouble-free running. Thanks for the insight and for underlining the high importance of plugging those holes whilst de-coking!
All the best
Steve
Hi Steve,
I have found your post most informative as I am having the exact same trouble with my E Class 2.7 diesel. I particularly agreed with your rant at the start. Is the Sprinter the same engine as I am considering putting the 8mm bolt in to make it stronger? Also, I was wondering if there is enough wall to put in an 8mm helicoil.
Thanks for a first class post
John Abeyta
Hi there John,
The trouble is that the threaded portion is only that which exists below the rocker cover clearance hole. Although the 8mm bolt idea is great you would have to get an engineering company or some friend with a lathe to turn the base of the cap head into a dome mating similar to that on the original clamp bolt. This is important as it distributes the angular forces correctly onto the clamp. As I am sure you can imagine a flat surface here on clamping this down would cause some issues. I considered using a standard 8mm cap head bolt with a specially made dome under washer that fitted the clamp correctly. Apart from that there is no reason I can see why you cant do this. There is ample material radially but the depth is critical so as not to break through into the water jacket. Interestingly the commercial repair inserts are blind at the base and not thru.
All the best
Steve
I had a jammed injector and while the engine was still warm, I put about 1 table spoon of diesel around the injector, let it soak for about half an hour. Clamp the injector body with a pair of vice grips and slowly wriggle it back and forth, slowly but surely the injector came out after about half an hour. I also found those injector seating tools chatter and leaveg grooves in the alloy seat.
I had a helicoil installed on number 4 injector “318 cdi”. Lasted about 6 months. It did let go. Look up Time Sert thread repairer. Or use an 8 mm stud like I did.
Hi Ken,
Thanks for the input, the timesert is the best solution and is my recommendation in the text, however you can engineer or get engineered a similar blind ‘plug’ made out of stainless steel if you have the use of a lathe and the capability – Though for a one-off you would certainly use timesert. While I hear you about the hold down bolt, I am of the opinion that the stretch to yield bolt and its slightly ‘elastic properties’ may maintain a more consistent clamping force through an ever changing range of temperatures (slight expansion and contraction of each use of the engine) rather than a stud fixing – that is not to say it would not work just perfect for you just my opinion !
All the best
Steve
Thanks…Great article…BUT…..any advice please
Managed to replace the copper washers on the first 2 injectors and replaced the stretch bolts….all back together……only thing is she just won’t start.
Bled the fuel to the injectors.
Tried easy start and tow starting.
Used battery pack for starting.
Already replaced glow plugs and tested for power to glow plugs.
Already replaced seals on the fuel bar.
When tow starting she fired a little, abit like when you start the van with the key without the chip in (we weren’t using the wrong key)
So….if anyone has any advice, it would be most welcome…..we couldn’t run diagnostics because we don’t have the right connector for OBD port…..
Hi Matt,
Sometimes a section of the push on electrical connector to the injectors breaks and goes inside the connector preventing proper coupling of the plug. If one injector is not connected it will not run. Also check wiring from the plugs to the loom it may have been damaged. Pay special attention to the camshaft sensor at the rear of the rocker cover and make sure there has been no damage to those wires during the injector removal replacement process. Check too the ECU fuse under the steering column, no power here and this will hold off any starting.
Hope these few pointers help.
Regards
Steve
Great write up M8. Lotz similar on forums but never enough info there.
Had small build up on last injector on our 639. try to change washer and of course when through water jacket :(( also didnt re cut injector seat for good fit so once injector was in place was still leaking diesel ;(( just order some new bolts and washers.
Will shere results once done
Hi Lucas,
Thank you for the feedback. Breaking through into the water jacket is not a huge problem if all the threads still exist in the hole, you can just add a small bead of silicone sealant to the pins threads before re-installing this should sort that out.
Good luck.
Steve
I have took three ijectors out one will not move top broke off the only way i can thinkof gettin it out is to drill down the center tap it and puta larg bult in to grab and pull it out will it be wise to put some heat on it the pull it out spent two days on that one not move i drill the top of it put clamp on fitted to engin lift and put full weight on clap broke engin lift was air bourn hell of a bang broke lift any advice
Hi William,
I feel for you, its a poor situation to be in. If you feel you can have a go without the risk of damage to the head give it a try. If the head of the injector has broken off cleanly it may be possible to remove the rocker cover, pulling it off over the stub to reveal a little more of the injector to grab hold of but I am unsure at what point it has broken. There are several companies that specialise in removal of broken injectors but now the vehicle is immobilised the only option is to remove the head and send it to them for the work. Good luck – it really is a terrible situation to be in.
Give these guys a call in Yorkshire if in the UK see what they advise. http://www.apautodiagnostics.com/
All the best
Steve
i had this problem on my 2002 110cdi vito dualiner and let a local garage do it and they have made a right pigs ear of it and they have snapped an injector bolt. any suggestions on where or who can help me in or around newcastle
Hi Matt,
Try these people out: http://www.apautodiagnostics.com/ (Yorkshire) or these http://www.injector-removal-service.co.uk/ (National) or try here there may be some one near you who can help.
I hope its of some help.
All the best
Steve
Hi great advice column, I have removed and reassembled the top half of the injectors
Along with the obligatory copper gasket, used the BGS technic tools
The vito 112 CDI ran rough, but came better after about 5 minutes.
Took it for a run, and upon doing a u turn and accelerating the ETC light came on.Lost all power. Waited a minute and started On, drove home slowly. The EDC has not come back on.
Your thoughts?
Also a warning to any one whom is intending to use these specialist tools, the tool grips the injector on an internal thread, so you are required to remove the solenoid, upper spring bonnet assembly, Critical to use a magnet as there is small steel ball (check valve )
Only 1.33mm diameter & cap if you loose it your in trouble.
Follow on , motor sounds sweeter, but on acceleration EDC Comes and kills the motor!
Hi Les,
its worth checking the electrical connectors to the injectors and make sure they are seated correctly and fully home. Check the turbo vac connections and determine you have boost (you should hear it and it should pressurise the pipes) Check you are not losing boost through the induction pipe or manifold (you should hear this) also make sure you have not disturbed the boost pressure sensor on the plastic intermediate pipe between intercooler and inlet manifold during the operation. You really need a code read to see where to go next. Thanks for the write-up on the ball bearing tip.
All the best
Steve
Hi, Interesting topic.. I have a Merc C270 that has been botched in terms of the Injector bolt hole but have sorted that out. Fitted new seals but still have a slight leak so am going to cut new seats. I have bought the Honda washers but the question I have is what type of seat should I be cutting..a domed seat or a flat. looking at the seals they are slightly domed and logic would dictate the use of a domed cutter. Hope someone can offer up some quick advice . Steve
Hi there,
The mating faces of the head are cut flat and washer compresses and deforms to make a gas tight seal, well that’s the idea anyway. You can get relatively cheap tools to recut the face, its rather like an end mill attached to an arbour to keep it parallel to the bore.
Good luck, all the best Steve
good day
firstly I would like to say that the comments etc are very well documented and very helpful, the question I would like to ask is if all 4 injectors have been removed and then replaced in any random order would this effect the running of the engine,i had mine removed and the injector seats machined and from then the vehicle does not want to run properly.
sorry I forgot to mention that I have a 2009 Mercedes vito
Hi There,
Assuming that there is no diesel leaking from the recut seals and all is fine, tight and dry then I would check out the electrical connectors to the injectors, make sure they are fully home and clicked in, if the tabs have been broken use tie wraps to hold the plugs in tight. Each injector is ‘classified’ or calibrated by a dealer diagnostic tool, to each cylinder so you may expect some running issues. In my own experience, this is only a ‘fine tuning’ and to be honest the engine should run 80-90 per cent good, if its rough and very poor look for other related troubles.
When the injectors were removed from the head, did they use a slide hammer tool to remove them that screw fits on the inside of the injector? With these you have to remove the injector solenoid, there is a danger if this is done that parts are dislodged or lost (small ball bearings etc) from the solenoid mechanism of the injector. If of course the heads of the units have not been disturbed – discount this. Look for damage to the wiring in the loom on the head by the injector rail, especially to the camshaft sensor on the rocker cover rear as this can get pinched if care is not taken when removing the rearward injector.
I hope this helps you out in some way.
All the best
Steve
thanks Steve I will try this and give you some feed back
Regards
Dinkey
Hi Steve, Cracking article on doing the injector seal repair. Can you tell me, do you have an article on removing cylinder head from a 2004 Vito 109 639?
Thanks in advance
Cheers
Dunk
Hi Dunk,
I suppose because its such a dirty job and time consuming I have never taken pictures as I have worked and to be honest they tell the story a lot better than the written word. As your vehicle is a 2004 W639 rear wheel drive the power plant is the same as a 4 cylinder sprinter and there is this excellent article here that should give you all the pointers you need, just imagine its on a Vito and accept there will be some minor differences to ancillaries and pipework, but in general you should be go to go with this.
http://sprintervanconversion.weebly.com/cylinder-head-removal.html
Thanks for the positive comments, I hope this helps you out.
All the best Steve
Hi Steve
Thanks for the fast reply & the link to this information, it is much appreciated
Keep up the great work
Cheers
Dunk
Hi Steve, I have finally started this job on my Vito 2004 109 639
With a lot of luck, I have no 3 injector out and cleaned up, My question is, should the seat in the head be flat or tapered?
I have purchased one of the seat cutting kits, and it states 17mm beveled for Mercedes CDI engines. I just wanted to check with someone who knows! 😉
The sealing end of the injector is flat if that helps
Thanks
Regards
Dunk
Hi Dunk,
The seat cutting tool I use is flat and not tapered seat. This works with the flat (ever so slightly dished copper washers that compress to seal) injector seals. As far as I am aware seat cutting tools are NOT tapered.
On the seat front you will need to find the two wires that go to the now unused belt receptacle and short the two wires together. If there is a seat occupancy sensor in there (which I doubt – however if so this could complicate things) but if as assumed above you have just 2 wires to the belt clip this should do the trick as it will always ‘think’ the belt is inserted and kill the warning.
All the best Steve
Hi Steve, Thanks once again for some great advice, it really is appreciated 🙂
Cheers
Dunk
Some Updates:
Injector Seal job, Seat re-cut flat & reassembled & running great! Thanks 😉
Seat warning light, I tried linking 2 wires, fault still exists, so I use a 3 ohm resistor from maplin, cleared code, Problem solved, Thanks, 🙂
Finally , on road test, engine warning lamp illuminated, no fault codes found, but on “live data” on my code reader, the ECT temperature is in red.
I have now found out that ECT = Engine Coolant Temp Sensor, Can you confirm location of the ECTS on Vito W639 ?
Thanks again for your excellent help!
Cheers
Dunk
Hi Dunk,
Its in the thermostat housing, it usually well stuck into the housing and will not come out. Best bet is fit a new Febi pattern part (Complete stat and housing assembly) as it contains a new sensor already fitted. You may be lucky and it comes out when you remove the retainer circlip – but I very much doubt it!
All the best
Steve
Also an off topic question.
I have fitted a single seat in lou of the twin passenger seat, is there a simple way of getting rid of the warning light that now appears as single seat has no sensor/switch fitted
Thanks
Regards
Dunk
Cheers Steve, I will have a look & give it a try
Cheers
Dunk
Hi
Thanks for the article, very enlightening. I’m wondering how often these seals are likely to fail?
I have an 04 213CDi and today discovered that I have a small coal mine on my injectors. I had some seals fail 2 years ago which ended up in me needing 4 new injectors as the garage mangled them (or some of them on removal). It cost me £1700 in total to have it repaired.
Since then I’ve only done around 18k miles and I’ve been told today that 2 seals have failed and the injectors are completely caked in black death.
Does that sound like the previous repair was substandard or could it be ‘just one of those things’ or symptomatic of something else?
It would be great to have some advice from those of you with experience of this type of fault before I go back to the garage (and possibly get fobbed/ripped off).
Thanks in advance
Andy
Hi Andy,
You have pretty much all the answers you require from Sprinter Source but I would add that quite probably the seats were not recut when the new seals were fitted. Once an injector begins to leak the blow-by will start to cut into the soft aluminium surface of the seat. Cleaning them up or light re-cutting with the correct tool will prepare them for new seals and give them the best chance. The injector hold down bolts need to be torqued to the correct rating. It would be interesting to see if you were charged for a set of new hold down bolts on the original repair invoice, as these are specialised stretch-bolts that once set to the correct tightness, allow a little ‘spring’ when the head expands contracts etc. So if the old bolts were used there is a chance this could be the root cause. It has been seen.
Good luck with the garage, though personally I would think after this time there is little chance of any recovery.
let me know
All the best
Steve
Thanks Steve,
Very informative again. I will try and locate the receipt, but I’m pretty sure that it was quite vague with the itemising.
I’m having an absolute nightmare with the damned van and just this week I’ve needed new glow plugs and camshaft sensor and then this morning came some horrible pop and rattle accompanied by a plume of smoke. Then non start, not turning over , then start with a rattle and plenty more exhaust smoke, then smooth driving ever since (well, for 10 miles or so) . I’m totally befuddled.
I might go outside and set fire to it and have a glass or 2 of wine.
Mmmm
Sounds like a backfire! Backfiring is usually caused by incorrect mixture not combusting (or failing to completely combust) whilst in the cylinder then igniting in the exhaust. All due to the poor sealing/worn injector/s I would wager.
Most likely could be that an injector is worn/damaged and is ‘leaking down’. When turned off, fuel from the pressurised fuel rail dribbles into a cylinder through a worn injector nozzle, this can cause larger than normal amounts of fuel to pool in the cylinder of a standing engine. When you come to start it could in severe cases ‘hydraulic’ the engine from turning over. When it eventually turns over and clears, it spews unburnt diesel into the exhaust that then uncontrollably ignites- POP ! The upset and explosion in the exhaust along with raw diesel will cause smoking until its all burnt off. When you get to taking out the injectors have them pressure tested (leak off test) at a specialist before refitting them, if you have any duff ones get them reconditioned or fit a replacement. This if not dealt with could damage the engine and will certainly cause starting problems in the future with either a hot or cold engine.
Good luck with the garage. If it was me – put it down to experience and go elsewhere – then sound like you know what you are talking about when you speak to them ! Tell them whats likely wrong and what you want doing. Sadly all this will not be cheap – so make sure the reception has a chair handy!
Steve
Hello all, Great write up. I did a bit of reading before carrying out this job as we mainly only work on VW commercial vehicles. So found this very helpful when doing sprinter injectors.
Would just like to add once you have got it stripped and all black death cleaned off, undo the clamp bolt slightly, re fit the inlet manifold plastic and pipe. take vehicle for a hard run and get the engine red hot. If you hear the chuffing get slightly worse even better as the injector has started to move(you should have only slightly undone clamp bolt!! do not take this bolt out too far or the injector could rip the thread out!! This worked great for me!!
Hi Craig,
Great input. I have read about this but never done it myself – so nice to hear its a tip that actually works!
Thanks again,
Steve
Hi there mine had this black death took me a day and half to clean off and take injector out. Ive put it all back together again but will not start even pulled it down the rd. I have a light on the dash( edc) i have turned this out 4-5 times but comes back on. Can someone help with this dont no what else to do.
Hi Tim,
There is a chance there is either an electrical connection issue on the injector plug, no connection or not connected properly of any injector will cause it to not start. Recheck the wiring and look for damage to loom, its easy done when cleaning that mess off! Also check the cam sensor at the back of the rocker cover, there is a short loom section that also goes over the injectors, make sure this is OK too.
All the best
Steve
Look at each injector plug, are they all sitting onto each injector properly? If one looks like it’s not on as far remove and clean. Also check if any of the lugs have snapped if so use zip ties to hold on. (You can buy the harness connectors from eBay if they have snapped but zip ties work just fine)
If it still won’t start look at all the other wiring that was covered In Black Death it may have been damaged (when cleaning)
Did the injectors come out ok or did you use a puller and spilt them?
Steve thanks for the write up.
Mine is the W639, 115. I’ve the start of the black death on the rear injector, the worst to get to.
From others responses I’m assuming the injector removal and seat clean up is possible without the need to remove the head.
Is the steel plate above the engine, and below the wipers, removable or is the job carried out with this in situ also ?
Hi Martin,
Yes you can remove the plate, it makes the job far easier and this plate would be removed if you needed to say remove the engine so although takes a while to remove will open up access for the job in hand. The rear most injector is always the worst to deal with either in Sprinter or Vito, some pullers are low height to allow you to use them within the confines if you get into trouble.
All the best
Steve
I have a 2005 Vito van which is chuffing and has the black death, do you have specific instructions to rectify this, is it that similar to the Sprinter ?, Here in New Zealand there are few or no mechanics who have dealt with the problem , because there a few Vitos. I am very mechanically minded but need some guide lines
Hi Peter, Currently I have not recorded the operation in either photographic or textual form, however if you have a look on the Sprinter forum I am pretty sure you will find all the help you will need there. You are not on your own ! Join up!http://sprinter-source.com/forum/
All the best
Steve
Hi Peter
I am in Cape Town, have a ’04 Vito which I’m about to attempt to deal with black death on #1 and #2 injectors. How did you get on?
I’m happy with it, she’s running again. Here is my best advice:
1. HOT. Get the engine hot to remove the injector clamp bolt. It’s only 6mm diameter and if you have the black goo already, it has run down the threads – ALL the way down – and has locked that bolt into the threaded hole. When hot, it gets very soft, like thick marshmallow, but is hard as glass when cold, so heat it up by running it to full temp. Trust me on this, I forgot on one and broke it off. This is a pain in the a## you don’t want.
2. DON’T take the injector head off of the body if you don’t have to. I did and regretted that too. Taking it off exposes several tiny loose bits inside the valve system and without even knowing it, I lost one of them. I killed the injector doing that (I suppose it can be put back together by someone who knows how and has the right pieces, but I’m not that person.) $540 US at the dealer for a new injector.
3. Stuff a wad of paper towel or small rag down the injector hole while you are cleaning up the goo. You don’t want anything falling into there.
4. Pull the glow plug on the cylinder you are working on. While you are cleaning out the bore hole for the injector, blow compressed air INTO the glow plug hole. This will push small pieces out the injector hole as you clean it off – again, you don’t want those pieces going into the cylinder, they could end up going through the turbo – don’t want that.
5. Fish out the old copper washer with a long screwdriver and a piece of metal wire bent into a U at the end.
6. I found a long metal rod about 18mm dia (I’m guessing here) and glued a piece of sandpaper to the end and trimmed to the same diameter as the rod. I put this down the injector bore and spun it with my fingers while putting some pressure on it to clean up the sealing surface in the head for the new copper washer. Don’t forget the compressed air in the glow plug hole.
7. Get an M6x1.0 thread tap and chase out the black goo from the injector clamp bolt holes. Run it down in and out, then blow out the hole with compressed air, blow off the tap with air and do it again and again until all the goo is out.
8. Get the ceramic grease Mercedes specs. I used it for the following: To hold the new copper washer onto the injector tip for re-install; On the body of the injector to make it easier to come out next time; On the threads of the injector bracket hold-down bolt and the threads of the glow plug, both to ease the next removal.
9. There’s a spec for the torque on the hold down clamp bolt followed by another 90 degree rotation. I don’t have a torque wrench, so I did it by feel, at my own risk. Seems ok.
10. You will need new bolts, they are torque to yield type. The extra 90 degree rotation permanently stretches the neck of the bolt and they cannot be used again. Obviously new copper seals are a must, they’re really cheap. I ordered and paid for 6 from the dealer. Their distributor shipped them the package quantity of 20 and they just gave them all to me for the price of 6 (I think they were 60 cents US each)
I left off the engine cover so far and I check it every couple days. The ‘chuffing’ sound that it made when it was leaking is gone and I don’t see any signs of a leak. I’m going to do the seals on all of them one at a time when I have some spare time coming up to prevent them from developing leaks too. Now that I’ve done it, I’m not as afraid of it any longer. 233,000+ miles and still runs great.
Great write-up, thank you Pete.
All the best
Steve
Great to see some contribution, I used the Honda copper gasket they sit tighter around the injector so they naturally stay located on the injector, when you install it.
The other day I could not get the ceramic grease so I used some loctite anti seize, trial and error -long term I will have to see how that goes. You did not say how you lifted the injector out, was this with a hydraulic device?
Thanks for the info Les,
I think Pete’s injector came out surprisingly freely once the engine was warm. I always run the engine to normal operating temp then slacken the hold down bolt and run the engine for a while more to allow the combustion pressure to unseat the injector. 8/10 times this works, for the other times – a lot of hard work!
All the best
Steve
Hi Steve,
great write up!! Just a couple of questions do you have the part no for the injectors seal/washers for the honda, going to replace my 05 sprinter 311, as black death has engulfed the tops of 1 & 2(but hoping its just inj. 1). Also does anyone have any tips on stopping any black death falling to cylinder, mate suggested an earplug..? Shame I never took the cover off ages ago as I’ve replaced hp pump, dropped tank, changed o’rings in bar chasing air in the fuel system…. anyway the end is near and hopefully I’ll be back on the road soon.
Cheers
Laurie
Hi Laurie,
The seals are from the Honda Accord 2.2 diesel, Honda garage will have stock, the exact part number I don’t have sorry. An earplug sounds a great idea!
Good luck.
All the best
Steve
Re Tip for Black Death into Cylnder:
When I did the “Black Death Job” on my Vito, I removed Glow Plug, Cut top off, Bored out centre & welded on a male PCL Airline fitting, then refitted to head. I then got a short piece of airline & fitted 1 x Male & 1 x Female PCL Fitting with a lever type ball valve at the Male end.
Connect the female net to the male that is now sticking out of cyl head and with the valve closed connect to workshop airline. Then gently open ball valve, this will allow a constant flow of air from the cylinder out via the injector hole.
This worked great for stopping any “curd” getting into cylinder during clean up & also during the re-cutting of the injector seat.
Obviously, inlet & exhaust valves have to be closed for this to be effective 😉
One point to note, is that when re-cutting seat with tool, you will be working against the air pressure in the cylinder but the bennifit of seeing the swarf blowing past your hands is great! 🙂
Please note, ALWAYS WEAR SAFTEY GLASSES OR FACE MASK
Good Luck
Incredible!
Thanks for the fantastic inspired tip Dunk.
Regards
Steve
No Problem Steve,
I am just grateful that I found your site and it brilliant advice. 🙂
Keep up the great work!
Cheers
I like the way you talk ! Last week I was driving my 519 2011 to work and lost 80% of power, looked in the mirror saw the smoke pulled over and waiting 4 hours to have a proper tow back to the Merc dealer. Imagined a piston ring or con rod had gone with only 45K Kms i was surprised. In the shop now out of warranty by 2 months and have been told the injector is the problem #4 to be precise. Was told Mercedes may most probably do a good will warranty for the parts. See how that goes next week. have you heard of this happening and what are the chances there has been damage to the cylinder? I could see how all this could be a one off experience since i pulled over within 60 seconds of the issue occurring. Your thoughts would be appreciated. i do love the Vehicle.
Hi there Douglas,
The effect of a faulty injector can over a prolonged period cause some overheating issues to the effected piston and/or valve components, the fact that your problem was short-lived and you reacted quickly to the situation should hold you in good fortune. I have a feeling once the injector is replaced and properly coded you will be good to go!
Let me know how you get on. All the best
Steve
Steve,
Like you said I was fortunate to be able to pull over in time before any damage was done. GrandMotors Mercedes, Gold coast gave me dealership in house full warranty replacement for the lot and included parts for the leaky coolant as well. Very happy that the only defective part was No#4 injector. I decided a full B maintenance or service was in order as well so with towing included a $952 donation was extracted with little tears from myself and I have my 516 4X4 back home. The service mgr was excellent and honest as well. I had a much better experience than I could have had if the engine had to be replaced and I had to pay a part of the cost as was initially suggested. Thanks again
Hi There
You seems to be a very lucky man.
I have just a 3 years old van 313 CDI being serviced a week ago at MB and found that 1 of the injectors are leaking. I told MB that it supposed to be seen 3 weeks ago when they checked the van (just before the warranty expired). As they said they “missed it but “no goodwill can be done” as it was out of warranty”. Ok, we got it done in a costly way.
The garage is a mile (1) from us and the very next day the van did not start. We called MB and they towed the van back to the garage. The result of their check was that the engine is now seized.
QUESTION:
Can anybody tell me whether a job with the injector could caused a seized engine (there was no alert light on the dashboard when the van was picked up after the injector service – everything seemed to be perfect).
Many thanks
Hi Norbert,
That is indeed a very sad tale. It is so hard to say what the issues were here, one can only assume that the two instances were unconnected. Most engine seizures are connected to oil starvation as a primary reason. There are indeed instances where engine seizures are caused by injectors that are worn, what happens there is the incorrect rate of fuel is injected and the piston melts over time, however I do find it hard to believe this happened to you – given you only drove the vehicle home one mile away after the repair!
There are many questions to ask of the dealer and to be honest it was poor form for them not to even split the difference on the cost of the original injector job, as clearly it was their negligence it was missed at inspection (within the warranty period). There was little to nothing to gain in the dealer not doing this injector work under warranty as its cost is all reclaimed back from MB central. So they missed it and should have really split the cost with you as a gesture of good will.
Still, all that is a mute point now, as the damage is done. What remains now is to find out the reason for engine failure by stripping down the engine to see what is found.
I am at a loss to see how this could have happened as a result of any work the dealer carried out, as the van travelled no distance after the repair before failure. It will be interesting to see what they/you find. Do report back and let me know what you discover.
Many thanks and for what it is worth good luck – you need some after this!
All the best
Steve
Hi Steve , my Vito Common rail 2005 had the black death and sure enough it was the copper washer with a gap in it. I bought an injector removal tool online and the injector came out smoothly, only when i put it back together with new washer and seat done the engine started and rattled and blew out clouds of white smoke!. A specialist told me i should never take the injector apart and now the engine will be toast.
I think i must have lost a part or parts of the injector but i only ran the engine for 5 seconds without revs. The tool I bought could not remove the injector without taking the top parts off the injector.
Do you think my engine is toast , what should i do next?
Hi Peter,
The piece most commonly lost using the screw on type of tool is the tiny ball bearing that sits in the injector top under the electrical plug-top solenoid assembly. Did you retain this piece? Either way the method of removal you used is commonplace and is often used by the specialists for stubborn injectors so don’t be too concerned about the method! Have a read here – http://sprinter-source.com/forum/showthread.php?t=21026
All the best and Seasons greetings.
Regards Steve
Hi there
I have a problem with my 1st injector blowing back from the sides of the injector out of the injector bore hole.Swopped the injector with the one next to it but left the copper washers in the bore holes. Still the same problem. Is this due to a bad copper washer or perhaps durt inside the bore hole? everytime it injects it blows back out of the side of the injector from the bore holes ?
Hi Shawn,
The copper washer is a ‘crush’ deformable washer that makes a seal between the steel injector body and the aluminium head. This must be replaced with new each time the injector is removed. If it still leaks after a new washer is fitted then there is a chance the seat of the hole is scored, either by the cutting action of escaping combustion gasses etc. This must be refaced or recut to afford a perfect seal.
I hope this helps,
All the best Steve
Hi there Steve,
Maybe you can help.
I own a 2004 C270 CDI. I noticed that some compression was passing #3 injector and sent it to the agents to replace all the copper seals. They also replaced 3 glow plugs. After this, i noticed that the vehicle has lost a lot o power. Sent it back to them and the traced the fault to a faulty inlet manifold, which I replaced, which made no difference. I then took it to another Mercedes agent and they had the car for a full day and could finf nothing wrong. Do you perhaps have some advise?
Regards
Lennard
Hi Lennard,
I would have a look at the wiring to the camshaft sensor at the back of the head rocker cover (LHS looking into the engine) this can be damaged/cut/crushed when they remove the injectors. You will see it runs in the same loom section as the injector wiring. All the injector cables will be OK as if only one is not connected the van just will not run. Do you have an EDC fault light? If not chances are you have a induction leak. Check the main long turbo pipe at the front that joins at the manifold, especially underneath where it commonly splits right where you cannot see it! Look for any oil staining around the hose connections to the intercooler, oil staining indicates a boost leak.
An outside chance is that when its been in for work one of the mechanics has caught his boot on the brake light switch above the pedal. Do you have brake lights? The switch is a dual contact arrangement, one side deals with illuminating the brake lights, the other signals the ECU that you are braking. If the ECU side of the switch goes faulty or is damaged (Common problem and a $30 fix – replace switch) then this will cause power loss as you describe and NO fault light. Also check the rear light clusters for corrosion especially the brake/side light bulbs as this too is a connected and common problem. Really you would do with getting a code read from an independent MB workshop, this will tell you if any codes are registered and will give a clue where to look.
All the best
Steve
hi there if i had this black death would it be affecting my fuel consumption i have a coach built merc sprinter 308 2001 2.2 cdi ice cream van drives great only does about 65 mph and will only rev to 3600/3800rpm i think i read on a forum that they should rev to 4200/4400rpm i am only getting 13/14 mpg it really is killing the business
thanks regards alex
Hi Alex, It all depends how bad it is, do you have it? Have you looked for the obvious signs? I think from what you describe your van is in Limp Home mode and the turbo disabled. I would first check or replace the brake pedal switch as this has this exact effect and its a cheap start! You really need to get a code read from a good independent MB dealer or else you run the risk of just buying parts and wasting money until you find the faulty one. £40 now to tell you where the fault lies will save you hundreds in the long run. Change the switch first though these are a really common failure.
All the best
Steve
cheers Steve i have replace the rear axle and the garage that done it cut the break sensor and that light is now on .. on the dash don’t suppose the wrong gearing on that axel would hamper my fuel that much would it? i was sold it as the right one for that van so i think it is right enough
regards alex
Hi Alex,
You need to sort the brake light circuit and swap the switch above the pedal first. The gear ratios are all very similar so as you say that is not your real problem. Once the fault is cured it will rev above 3200 and have a working turbo, if not get the codes read and work from there.
Steve
cheers buddy very much appreciated i will keep you posted
kindest regards alex
sorry do you mean the break light switch as my break light are working when pressed thanks
alex
Hi Alex, the switch is above the brake pedal. Its a twin contact affair, one side of the switch operates the brake lamps the other signals the engine management unit. It often fails on the engine management part of the switch causing limp home. It may not be this but its where I would start.
Steve
thanks for your quick response Steve and thanks for clarifying that
regards alex
hi again if the van was in limp mode would it go as fast as 60/65mph and would it not have some sort of engine management light on .. there are no lights on bar the brake sensor one thanks again alex
Limp home can be caused by many things, not all cause an EDC lamp (EML) to illuminate. Limp home disables the turbo and limits maximum revs to 3200rpm NOT maximum speed.
Regards
Steve
hi again buddy i have sorted out the brake indicator the wires were cut and touching each other i separated them and the yellow light has gone off i also checked again the revs and they are going up to either 3600 or 3700 but defo no more than that. can you tell me what dash light is in between the yellow brake light and hand brake i am concerned that there look like a piece of black insulating tape over it ???? very odd!!
kindest regards Alex
On the left hand of the LCD it should be (Right to Left) Hand brake applied, low oil level, brake linings low. To answer your question it should be ‘low oil level’
Regards Steve
ahhh ok that makes sense cause the LCD keeps beeping and coming up with oil -2.0 L i have checked the oil and it is always ok what will be causing this thanks. also what mpg should i be getting from this van.. if it is fully laden or nearly fully laden. and what is the max RPMit should go up to. also is it possible to run this van on veg oil or a veg oil mix and if so what would i need to do
again Steve thanks for all your advice regards alex
Guys
After having my ECB Light come on under load, I removed the injectors, as I also had signs of the black death on my vito, test on the injectors showed one frozen shut and the others returning too much fuel, I replaced all four injectors with new ones, the Vito is running sweet, starts better, and performs smoother. Also the ECB light went out.
I also installed the Honda accord injector gaskets, and replaced the injector bolts.
For anyone approaching this task, I would suggest you have the injectors removed as a full piece- hydraulically, separating the upper halves can be tricky.
I also soaked the injectors with throttle body cleaner for about 4 days, and I have also heard that eucalyptus oil is also very good for this, and less carcinogenic.
Trust this may help some one else having similar problems
Great tips Les, I am pleased you found the site information useful.
Thanks again
Steve
hi again steve sorry to as soooo many questions but if the DPF was blocked up would that stop the revs going up and hamper the fuel consumption
thanks again kindest regards alex
Hi there Alex. Do you have an aftermarket DPF for London LEZ? Your model at 2001 was not fitted with DPF as standard. If you read through the replies there has been a chap in London with aftermarket DPF that had similar problems, even though the manufacturers said the DPF was clean they did not check back pressure as part of their service. He removed it to test performance and all was OK. Faulty DPF. The oil level/condition sensor is mounted in the side of the sump, the wiring or plug itself is most likely broken.
Regards Steve
Yeah Steve…I am working on a small diesel leak for a customer at the right front of the right cylinder head….it looks to be a ninety degree nylon hose into a little metal port for possible low pressure diesel measurements. this is the 2012 v6 mb/sprinter… I can put a wire tie to join the hose more firmly in it’s mate and no leak….but not to trust down the road. I would call this leaker the test pressure port, but can find no id’s of the little funky part….as though it’s o ring is bad??
Marty Schreiber’
marty mechanic
831 345 6000 (usa)
Hi Marty,
That sounds like a bleeder point to remove air/prime the LP diesel line, its a little too late model for me to have a parts listing on this (I usually work inline 4/5cylinder models). I have had a quick look round and there seems nothing listed. Best bet is take a photograph on your phone and armed with VIN and engine number find a helpful MB commercial parts counter. Sorry I couldn’t be more help.
Worth noting the same base engine is used in E class, S class and CLS so even a good passenger car MB parts department could be able to help you out.
Regards
Steve
nice thread some very usefull information keep it up guys thks john.
Many thanks for the kind words John.
All the best Steve
Hello when one of the Injectors is bad do you need to replace all 5 I have a 2004 sprinter 2500
Hi Adrian,
It all depends, you can just replace the one if the others pass a leak-down test. It may just be that your budget does not allow the replacement of all injectors. Just like spark plugs, they do have a lifespan and one failing could be an indication that all are also nearing end of life.
I hope that helps.
All the best
Steve
I have a 2012 vito sport its done 31000 miles and has been in the garage seven times to have new injectors fitted, all four were replaced 200 miles ago. today I have fumes in the cab and loss of power any advise please
Hi Beverley,
You have my sympathies.
If I were to guess, I would put my money on the injector seats being irregular and scored. Caused by previous leaking injectors. It is essential to inspect the seating surface in the head, as simply fitting a new copper washer/seal would not provide the suitable gas-tight seal required. Alloy is soft in respect of the cutting action of hot exhaust gasses under extreme pressure. It is quite a simple task to lightly recut and clean the injector seat with the correct tool. Just to give everything the very best chance of sealing, selecting the Honda copper washers is key, as they are a little softer in composition to the Mercedes OE ones and are able to distort/crush forgivingly on clamp down, helping to take out any remaining irregularities between the seat and injector body.
Hope this helps.
Regards
Steve
Thank you for your reply. I will try to tactfully pass this on to the garage. I am amazed that this Problem is still occurring. It is very frustrating and I am trying very hard not to shout at them.
No problem Beverley,
Let me know how you get on.
All the best
Steve
Hey Beverly, shouting some times works, throw a wobbly, kick and scream, and if you have young children, threaten to leave them in theIr office, with lots of red drinks, until the injectors are fixed. Last resort LOL.
Otherwise start softly.
Steve is on the money, with good advice, at least you are armed with the knowledge to solve the issue Good luck
Hi. No young children. But last time it broke we were 169 miles from home with six dogs!! The question is how many times do they have to fix it before it works. Seven lots of new injectors and it still breaks is bad news. I was hoping by now they would have fixed it for good. It is the main dealers working on it.
Hi again Beverley,
Have a read of Chris’s post in reply to Martin in this thread. I am not a single voice on this repair procedure.
All the best
Steve
I would put it back on Mercedes, they should warrant their own workmanship. Most OEM will do so.
Dogs are even better, unconditional love.
Steve, your advice here is invaluable. As I haven’t been in need of my Vito I have let the snow and colder weather pass before attempting the ‘Black Death’ repair outside on my drive.
A couple of points though.
I see you recommend the softer Honda copper crush washers. I can see the advantage but isn’t there a danger that the tightening down of the clamping stretch bolt will now not be as designed? That is will there still be the same clamping force?
As the bolts are stretch bolts I am replacing this also, and have been advised to apply a little MB ceramic grease to the injector body. This should help future removal where it may be required again in future.
http://www.ebay.co.uk/itm/121507497817?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Hi Martin, like you I was a little unsure about the validity and engineering safety in using the Honda injector washers. But I have recently had all four of my 1999 108CDI’s injectors out – for the umpteenth time – to cure yet another leak, and on that occasion finally decided to use the Honda washers that I had bought earlier.
Needless to say, I wish I had known about them the first time round, and fitted them much sooner; they would have saved me an awful lot of time and effort. Since then the van has covered more than 500 hard motorway miles, and there is not a sign of the dreaded ‘chuffing’, or fumes in the cab.
I am not sufficiently qualified to comment on whether, with the Honda washers, the ‘stretch’ injector retaining screws will be performing exactly as per M-B intended, but there can’t be much difference, if any – and I concluded that I had nothing to lose by trying.
I have always fitted brand-new injector screws each time I have removed the injectors, by the way, and have taken great care to make sure that their threaded holes in the cylinder head are absolutely clean and dry before fitting them. I bought a specially long M6 tap for that purpose, gently winding it in and out with the aid of a piece of small-bore plastic pipe pushed tightly over the upper end of the tap.
Don’t forget the required torque for the injector screws: ie 7Nm, plus a further 90 degrees of rotation. (You will, of course, need a suitably low-scale torque wrench, probably with 1/4-inch drive. I bought one from Laser, via Amazon)
No less crucial than all that, though, is to make sure that the face at the bottom of the injector hole, against which sits the copper washer, is clean, smooth and flat. Again, Laser/Amazon do a seat cutter for this exact purpose. Omit that step – as I admit that I did the first couple of times I did this job – and you are pretty much wasting your time.
Finally, yes, I think it’s vital to use that special M-B ceramic grease. It’s quite expensive, as I recall, but do it by the book and you are giving yourself the optimum chance of success. I’m not sure what it’s meant to do (except, perhaps, prevent the injector stems corroding if they get wet, which is possible if the engine’s top cover is missing, like mine), but it will certainly help get the injectors out again if you ever need to.
Good luck,
Chris
A comprehensive reply Chris.
I understand that at some later date MB have added to the procedure.
7Nm + 90 degrees + 90 degrees.
Clearly the extra 90 degrees would have a greater effect on the copper washer.
I’m sure I will be sweating some while adding the latter 90. Trusting MB to know best is perhaps questionable as if they did know so much this black death would not be so common.
I also drive a C320 CDI, that being the v block, and apparently the revised design has prevented that engine from suffering the same issue. Wouldn’t you think they would have revised the later 4 and 5 pots designs instead of just saying “tighten it more”?
The wife drives the Gr Cherokee with the 2.7 5 pot (excellent engine), but if either of the 2 rear pots suffer this it’s head off to repair. Shame really she has a pretty head.
Anyway, my intention is to grind the bottom of a removed stretch bolt flat, cut a groove in the thread, and use that as my cleaning tap. Of course being cautious not to compress any debri in the bottom of the hole (that could puncture the head) and not to bottom the bolt with any force.
Hi Martin, thanks for that update re the tightening torque. In fact, it was the search for that obviously vital data that brought me to Steve’s excellent website in the first place.
Steve, is that correct for the 108 engine, ie 7Nm plus 90 deg plus 90 deg? If so, could I (should I?) further tighten the bolts currently in my engine, or will the fact that they have been heated and cooled cause them to stretch too far?
All the best,
Chris Horton
Hi Chris/Martin.
The Honda washers are ‘softer’ (unmeasured science, but you can tell) and I have always consciously never bothered with the extra and last 90 degrees crank. Never had any trouble.
Each 90 degree rotation past 7 Nm with a new clamp bolt and clean hole results in a further 0.3mm stretch bolt yield, so my view has always been – softer composition, less crush and a little less beads of sweat on the final swing of the wrench! (Those threads are a weakness) Correct spec by the book with thinner less malleable copper MB washers is 7Nm +90 +90.
The full factual reference write up is here, I always have agreed with the final conclusion that offers this:
Tightening the fresh hold down bolt and seal ring will produce the same clamping force (defined by seal ring crush thickness) regardless of which of the 2 torque specs are used.
The desired residual bolt stress (to achieve essentially infinite cyclical fatigue life) is achieved by both specs but the 2X 90 spec does allow for less care and precision during the tightening procedure.
Torque spec #1 (62in/lbs +90) is certainly less risky if contamination may be lurking at the bottom of the very deep blind bolt hole. I suspect it is also somewhat less risky if the aluminum threads are not in ‘as new’ condition.
“Here at the Global Sprinter Research Center I am always eager to investigate Sprinter related technical issues.
Group members have noticed that Mercedes Benz has a published torque spec for the injector hold down bolts that seemingly differs significantly from the long standing DC published specs as shown in DC workshop manuals as well as on the instruction sheets that DC at one time included with replacement injectors.
The extended threaded shank length, 85.83mm long, 6.0mm dia., 8.8 grade, factory hold down bolt, hold down pawl and injector seal ring are identical part numbers for both the 5 cyl. and 6 cyl. engines.
Using my ‘test’ 647 Sprinter cylinder head, which is permanently mounted to one of my work benches, I have recently performed tests related to hold down bolt torque.
This dedicated ‘test’ cyl head has been quite useful in my repair tooling fabrication.
As many of you know I have developed in-house tools and fixtures for removal of broken hold down bolts, repair to stronger than new stripped hold down threads, and various custom black death repair tools for my in-house use.
This test head features my custom carbon steel hold down threads making it ideal for these hold down bolt torque experiments because data is not compromised by any aluminum thread deformation or failure.
After careful measuring of bolt length (before and after torquing) and injector seat seal thickness to 0.01mm tolerance, and using a calibrated Snap-on electronic 1/4 inch drive torque wrench set to display in/lbs and accurate to 0.1 in/lbs, I have the following observations to report:
TRIAL 1- A fresh, factory hold down bolt torqued to 62 in/lbs (approx 7 Nm) and then an additional 90 degrees, results in 0.08mm crush of a fresh factory seal ring.
The Sprinter’s copper seat seal ring features a double convex cross section and the clamping force induced ‘crush’ creates narrow sealing flats on each side of the ring.
Monitoring the bolt torque during the 90 degree rotation reveals a peak of 180-190 in/lbs before full 90 degrees is achieved and remains at this level all the way to 90 degrees. This peak/plateau signals bolt yield has occurred.
TRIAL 2- A new seal ring and a fresh, factory hold down bolt torqued to 62 in/lbs. (approx. 7Nm) and then an additional 90 degrees X2 (FULL 180 degrees), results in the same 0.08mm crush of the seal ring as well as a steady 180-190 in/lbs torque reading during angle tightening.
Being a stretch to yield, non-reuse, bolt it was not surprising to see permanent elongation. Elongation was approx. 0.30mm for each increment of 90 degrees of tightening rotation (after the 62 in/lb initial torque).
TRIAL 3-A fresh hold down bolt tightened to failure. The bolt tolerated several additional 90 degree sequences PAST the initial 62 in/lbs and 2×90 degrees.
It has previously been reported that fresh hold down bolts have failed when several group members had torqued to 62 in/lbs and then 180 degrees (mistaking 1/2 turn for 90 degrees).
I now suspect this occurred because of bolt bottoming in the base of the blind bore. Bottoming can occur because of debris at bottom of the blind hole.
CONCLUSION:
Tightening the fresh hold down bolt and seal ring will produce the same clamping force (defined by seal ring crush thickness) regardless of which of the 2 torque specs are used.
The desired residual bolt stress (to achieve essentially infinite cyclical fatigue life) is achieved by both specs but the 2X 90 spec does allow for less care and precision during the tightening procedure.
Torque spec #1 (62in/lbs +90) is certainly less risky if contamination may be lurking at the bottom of the very deep blind bolt hole. I suspect it is also somewhat less risky if the aluminum threads are not in ‘as new’ condition.
Be sure you test your cyl head’s bolt hole threads by using a wire brushed used hold down bolt with an indexing paint mark, turning in by hand while counting turns, to assure threads are clean and bore is unobstructed to full depth.
This is especially critical when performing black death surgery.
Andy Bittenbinder ”
All the best
Steve
It’s not clear who wrote this text above – was it you, Steve Ball, or Andy Bittenbinder? Either way, it’s brilliant. Proper, no-nonsense information, written by an engineer for those of us who aren’t but who do have at least an idea why accurate torque wrenches are so essential when repairing modern vehicles.
Hi Chris,
This was Andy Bittenbinder’s research and write-up. He is a Porsche factory trained engineer who now has his own auto business in the States, specialising in Sprinter vehicles and conversions (RVs). I can’t think of any better background expertise to be able to offer and qualify this kind of good quality reliable information on Sprinter/Mercedes based issues. 😉
Regards
Steve
I’ve been frequenting the MBO forum for many years, I am M80. Like here it has been a fantastic source of help for me. It is only recently that van owners have been contributing so my Vito questions were not getting much response, if any.
As with any forum you need to be careful of the wannabe experts Like me perhaps), in general though the technical contributions are knowledgeable and mature.
http://forums.mercedesclub.org.uk/showthread.php?t=71096&page=5
Post 41 here is where I got my information.
Extra thought,
if you do choose to add the extra 90 degrees it may be worth considering new bolts, again.
Only an extra few quids and pretty insignificant when you consider the effort involved.
Thanks Steve, the Andy Bittenbinder report is excellent and strongly suggests that if good preparation is carried out then there is no need for the extra 90 degrees.
I wonder if the 5 and 6 pot engines mentioned are both the in line rather than the more recent V6, are the part numbers the same for the V6?
Hi Martin,
This would suggest its the same ‘Kit’ that is hold down bolt, clamp and washer for all of the ranges shown (cant immediately see any not covered – one size fits all!) Specifically and including the OM642 (V6)
Andy Bittenbinder did more work on the clamp bolt testing than I ever did in any testing! I suppose that is the reason I will always go with the one 90 degree tweak. There is proven, just not enough benefit to be gained by going the full nine yards – hence that 7Nm +90 has always been the procedure I have adopted and originally published here. Touch wood, had no failures thus far.
All the best
Steve
I’ve researched thoroughly, but have not come across any advice on how to relieve the fuel rail pressure at the start of the disassembly process. Can anyone offer some help here?
Thanks,
Pete
Hi Pete,
Once the engine has been standing for a few minutes the pressure in the rail is residual. Residual because there is no flow or volume of diesel being pumped. Just place a rag over one of the injector unions and crack open the seal, after the initial release (notably hardly anything) it will be fine to work on the rail and associated components. The dangers of working on a pressurised CDI system are really when it is running and this should be avoided in all but the most precautionary of circumstances.
All the best
Steve
Steve, Great. I suspected such, but needed that confirmation. My black death injector leak fix begins next weekend.
Anyone have any advice on where I could send injectors to be rebuilt? What should I expect to pay for it. I don’t think my injectors are bad, but since they’re out, I’m going to rebuild them.
Hi Pete,
If you do a quick scan of the diesel engineers in your area (should be some) they will have all the tackle to test and service the injectors. Every large town has a diesel engineer as most commercial vehicle garages rely on them for their services to fleet and lorry markets. Best bet is to pop round with the goods and have a chat. Be sure to mark which injector came from what cylinder location as these injectors, like most these days are electronically coded to an engine location in the ECU. Whilst you can get away with juggling them around, performance may suffer as the coding effects marginally dwell and duration of the injection pulse. (Its like a factory fine tuning adjustment!) Just best to avoid mixing them up if you can.
Regards
Steve
Steve, Great advice, thanks again.
However, other questions have come to mind. If I were to replace any or all of these injectors with new, how would I go about dialing in that tuning for the new injector(s)? Likewise, if I were to have them rebuilt, their performance characteristics would change and therefore the tuning would then be off. Can the dealer do this? Does the car “learn” the new injector characteristics based on sensor readings?
FYI, those injectors have 231k miles on them and are undoubtedly tired. Having said that, the car starts and runs great despite of the 2 leaking seals and the -21F temperatures we’ve had here lately.
My main goal is to correct the leaks, but it seemed like a good time to have them rebuilt while they are out of the head, but if it runs well and changing the characteristics of the injector(s) will screw up how well the engine runs, maybe I just let it be and only fix the seals. What do you think?
Hi Pete,
I had forgotten to add that testing at our local depot is £15 each, refunded against any repair/refurb.
I was careful to say that coding is a ‘fine adjustment’ and to be truthful in my experience makes hardly any difference, I suppose it may be more noticeable in a new vehicle, but a 200k+ miler will have more intolerances in its general running order to deal with than this ‘micro-adjustment’ it would seem. In the case of fitting a new injector the MB procedure is to enter the unique 7 digit code on Star (MB Dealer level Scan tool) ‘classifying’ the new injector to the ECU.
It has been reported by many who have not bothered, (when fitting new or used parts) that omitting this classification procedure makes no noticeable real world difference to the running of their vehicle (T1N models specifically, things could be a whole lot different for the NCV3 07-on models, I don’t know…) Without doubt the dealer would do it, but most DIY’ers would not bother. The important thing to do is always try and get them back in the locations from where they were removed, this will aim to minimise any anomalies.
If I were to guess, I would say the adjustment or ‘classification’ of an injector relates more to ‘pairing’ the exact electrical characteristics of the piezo/solenoid part of the injector to the ECU and less of an adjustment to its mechanical function – that would be the bit cleaned/replaced in any refurbishment. Seems logical to me, although this is only my own personal 2cents guess and may not be valid.
Certainly your diesel expert will be able to offer a cleaning service if the injectors prove OK, what’s the harm in having them tested while they are out?
You could get an idea if the injectors were worn before removing them from the engine by conducting what is called a leak-off test. You will find details here, this would give you at least an idea of what lay ahead both financially and mechanically and I suppose could sway your trip to the diesel expert.
As for the seals only being replaced – Remember the saying – if it ‘aint broke don’t fix it! – That one is entirely up to you…
All the best
Steve
They do warrant the work. But that doesent help really. I want a van that gets me to my destination. MB won’t replace or buy back because of the age and mileage. So I must conclude that a MB diesel engine has come to the end of it’s useful life at 30000 miles and two and a half years old !!!
You may be right, but at 295k miles that mine has we shall see over the coming years
Hope I’m in the right place, great to read through the posts as it seems all mechanics are quite good at guessing…
I currently have a vito 111 xlw 2.2cdi manual 54 reg.
Having issues with a knocking/diesel tapping nosie, but only seems to appear once under load, I’ve been told all sorts of rubbish from different people, but after I’ve had a few good runs out I personally think it’s injector problem, I only bought the van 3-4 months ago it’s got lots of history of new clutch, recon gear box fly wheel, services etc…. Amongst the pile I have a receipt for overhaul injectors new seals and bolts in October 13, less than 10,000 miles ago, could this still be the problem is basically my question or should I be looking elsewhere?
Any help or basic checks I can do would be much appreciated…..
Also I’ve had it scanned and nothing showed up apart from glow plugs I’ve replaced these.
HI Martin,
I would first see if the vac pump is noisy as this is a common problem. Pressing the brake pedal and taking some vac load from the pump to the servo will immediately stop the noise if it is connected to the vac pump itself. It is unlikely the injectors are problematic if they were serviced recently and correctly, all at the same time. There has been some reported increase in engine note (tapping noise) when the EGR is partially open under load, usually this is when under the warm up cycle, obviously when it occurs at other times the valve is sticking and not closing properly. There was a 2007/8 recall on premature EGR failure and many were swapped under warranty. Any MB dealer will tell you if your van was rectified under recall.
If the EGR was sticking open though, normally I would expect an engine warning lamp, power loss and some black smoke produced from the exhaust under load when it was making the noise, but not in every combination of circumstances.
It is possible to test the injectors in situ in a very basic way by conducting a leak off test. This is well documented on the web for the sprinter vans (same engine) and there is little point in me repeating what is already available elsewhere.
I would also try and eliminate any possibility that there a slightly worn con rod little end, you should be able to reproduce this noise by carefully revving the engine and listening at the point of overrun once you toe off the power.
Hope that helps a little.
All the best
Steve
Thanks for the response steve much appreciated, funny you mention the break that is a bit spongy, they work but bit soft thought this was just the norm.
How do I check the servo/vac pump, do I have it running as the noise only really kicks in when being driven? I’m pretty lost with it all to be honest, I’m not to bad with a bag of spinners an some wd40 but I pretty much need it in lea-mans terms to put my hands to the graft! Sorry for being a pain….
Cheers.
Martin.
Hi Martin,
Not a problem. The pump will usually make a similar noise at idle too, though much less. when you press the brake the noise should disappear. Get someone to press the brake in the cab while you use your ears under the bonnet. The MB brakes are like that through the model range, sprinters will drop the pedal to the floor if you stand on it hard and just keep pressure on, almost like creep. Its the nature of the beast and does not effect brake force. It is designed like this to give a progressive feel – apparently!.
Regards
Steve
Hi steve again thanks, there is no noise at idle, or reving from static…only when I’m driving will it occur, when driving with clutch in and revs on it occurs also, but not at 900rpm (static).
Hope this helps… Maybe tappits but there is no noise difference from cold or warm once driving?
Hi Martin,
Just to help establish whether it is abnormal diesel knock due to any would-be fuelling issues, try a fill of BP Ultimate diesel or use a Cetane diesel octane booster and see if the knock is less. If so it more or less eliminates any mechanical problems, piston slap, valve train etc. That’s a cheap first place to start.
All the best
Steve
Thanks steve ill do this tomorrow and go for a good run, the noise is quite excessive though, I wouldn’t think its general shitty fuel as it has occurred from when I bought the van at first I assumed it was a cracked manifold but no joy after checking, I drove the van from London to Manchester so a full tank and the noise has worsened. I was going to try Lucas additive in the oil incase it was the Tapp, I’m also going to try and fill over the injectors with wd40 tomorrow and just ensure there is no leaks.
Checking is cheaper than wrong fixing…. And I don’t like to be beat!
As I said its baffling
Driven it today took it for a good run an the noise is worsening, I’ve also noticed there is now a puff of black smoke at lie revs when static, I’m becoming more worried it maybe Black Death!
Different Martin responding.
If black death you would normally get the exhaust type smell in the cab.
Lifting the engine covers you should see the black tar developing around the base and upwards of the faulty injector.
You might consider faulty hydraulic tappets, if someone has put a thicker or cheaper oil in that might cause that. Or indeed if oil has been left far too long.
I notice you say tick over is 900, 700 is usual. Could the ECU be over fuelling as well?
You faulty injector theory sounds reasonable though.
tick over is below 900, going to get it to Mercedes specialist tomorrow and get them to diagnose and give me the bad news then… Just don’t want to be ripped off for something that won’t cure the fault as happening in many garages, miss diagnostics an charge for work…..
Martin,
Filling with a higher Cetane rated fuel like BP ultimate (like higher octane) usually has some effect if the problem is directly fuel related, ie injectors, or diesel knock, in other words the noise would normally be expected to be less. This is a good old simple test to see if the problem could be pinpointed as fuel related or mechanical. Obviously if there is a mechanical knock – tappet, little end, rod etc it would not generally ‘go away’ or alter when changing to a higher Cetane rated fuel.
What is the fuel economy like? mid 30’s?
A Leak off test would also give you a ‘quick and dirty’ indication of injector condition. Just suitable plastic tubing, cut and placed over the fuel return lines on each injector, pull off the cam sensor and crank the engine for the designated period. The level of diesel in each of the tubes indicates overall leak-off and gives an insight into the condition of the injectors.
(Martin no.1 🙂 ) – My view is that you would be more likely to notice a tappet noise louder and heavier at idle than when under load at higher engine rpms.
Regards,
Steve
Good point on the tappets Steve.
Hi, we have a MB workshop and have experienced a problem of late, quite strange, we have a VITO in our workshop that we have been struggling with for a while, then another vito came in for a service, we tried to changed the injectors over, when we were done with our test, we put the injectors back in the same order, but when we started up the vito that came in for a service it had no POWER, its almost like the VITO corrupted the injectors, we did put them back in the same order and we did program them – checked the values on the star diagostics everything is in spec, this is the 2nd time we come across this problem.
Hi Rafeeq,
Like you I find that amazing.
What I cannot understand is why it is happening as there no electrical intelligence in the injectors at all, you even have to manually tell star the seven digit coding!
What I would be looking for if I was you, is a problem caused by physically swapping over the injectors. If you use a screw type injector puller that attaches to the top of the solenoid to extract it, was each one rebuilt perfectly in every case. As I am sure you well know, there is some delicate parts, including very small ball bearing that live just beneath that solenoid cover. I am pretty sure that if just one was rebuilt incorrectly r some contamination got in there, the rail pressure could suffer. Worth a look what the rail pressure reads, as this could hold off the power. Have a look at the leak off quantities – I suppose this would be a good quick indication if all was well.
The only other thing that I could imagine would have some effect is if there was a airlock in the fuel rail of some sort, this would compress under HP pumping and act like a ‘air-spring’ when you try and build injector pressure. Double check the fuel delivery components and rail thoroughly, if the ECU detects even a sniff of pressure drop on the rail HP circuit, it will hold back the power and not always flag a code.
A real off-the-wall suggestion, but has the camshaft position sensor been disturbed? These in my opinion are really sensitive to change once they have been in service for a year or two. If its been knocked, subject to tapping or twisting, sometimes even just removal, it may be worth just simply swapping it due to its relative low cost. I have had a range of issues with these sensors, developing the weirdest of faults without showing any MIL illumination – I suspect that it ‘miscounts’ rotational pulses. Also check the cam sensor wring for breakage chafing, especially at the point as it lays through that guide groove on the alloy rocker cover casting.
Finally, just check for correct brake lamp operation, make sure it is flagging correctly on star. I did have once an occasion where clumsily struggling to get in and out of the cab in a crowded workshop, I caught the brake lamp switch with my boot and knocked it slightly. I still had brake lamps but no ECU brake applied signal – hence no boost or indication of any problem. Replacing the switch cured the issue, but I wont tell you how many days it took to put the problem right as I immediately thought the issue was due to the work I had recently done and not through catching the switch with my size 10 !
I hope you have a few pointers there to check out, if its done nothing other than make you think it though in another way it might be of some help to you.
Let me know what you find.
All the best
Steve
Finally got round to completing this a few days ago. I fitted a new stat and glow plugs while at it, well 3 of 4 as the front is rounded. Now I can run the engine and to temp I’ll be spraying WD40 in to the recess and after a week(ish) I intend to drive a 9mm socket over the plug and try again while the engine is still hot.
I can’t see a better thread for my next question so hope this isn’t misplaced.
You may remember I haven’t been in a hurry to get the Vito on the road, now there is some urgency.
While stood water got into the SAM, with strange happenings. I sourced a same ID 2nd hand replacement believing it to be plug and play. All is now dry in the enclosure. I now have the ESP, ABS and BAS warnings up. I’ve tested the brake pedal switch, which had developed an over sensitive issue due to pedal being in contact, that’s now cured. So switch as should be on both n/o and n/c contacts.
Do you think I have a faulty replacement SAM?
The van needs an MOT and although running very nicely the warning lights would be an MOT failure.
Hi Martin,
Have you calibrated the steering angle sensor? Full Left to right lock a couple of times with engine running should reset this, especially relevant if you have had the battery removed.
All the best
Steve
Thanks for the swift response Steve.
Yes the battery has been replaced and I have taken the steering lock to lock a couple of times,
Using Torque lite I have reset any fault codes, several times. All with the engine running.
The only code I had was a ‘ou423’, that was a while ago before the engine works. I thought the injector issue may be causing that, or low battery voltage.
Hi Martin,
If you are 100 per cent sure the brake light switch is ok then next port of call would be wheel speed sensors. I think the SAM would not influence this problem because ECU/BAS takes its brake/stop signal from the switch and not the cluster control (rear SAM unit I think) The ABS etc. is totally separate. You may have a corroded tone wheel reluctor ring or just a poor connection somewhere with standing over winter. You will need to access the ABS brake system electronics to view any codes but that is where I would start. If the speedo works then discount the front passenger wheel speed sensor, as this is working OK! Just three more to go at… If you get all the lights on KOER, running and not moving it is probably high resistance open circuit you will be looking for, If it comes on when you get rolling then it could be rings/corrosion/air-gaps. You will probably need to clear down any other brake related codes manually, the only ones that will go away when fixed are wheel speed sensor faults.
Regards
Steve
Thanks Steve, I hadn’t considered the rear SAM.
The van has been suffering unbelievable levels of condensation, I’m fairly sure I’ve cured these issues now, ingress through top of w’screen and through rear barn door seal.
So a though I have is to if the rear SAM may have been affected by the condensation?
Where is it located?
Hi Martin,
I think what I was trying to say was the SAM unit (either front or rear, if that exists) did not take a brake/stop signal as this was taken from a mechanical brake switch. The fault I think may lie in the ABS circuit and you will need to access this controller to read/clear any codes. I am not sure the OBD reader tool you have will enable this. Possible fault with wheel sensor / connection.
Sorry for the confusion, probably not originally written in the most understandable way.
All the best Steve