strong diesel smell in cabin

Paul_E_D

Member
OK, I'm getting my van sorted little by little. Electrical gremlins at bay, now I'm looking for the source of intermittent diesel fumes in the cabin. I pulled the cover off of the injectors, they are quite clean, but not absolutely dry. See pictures. I'm not sure what to expect here, and what indicates the start of black death.

If not the injectors, then what could be causing the smell? The only leak I can see it the oil dripping at the turbo pipe, connector.

06 with 125k miles on it.
 

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sailquik

Well-known member
Paul E D,
On the OM-647 5 cylinder the 2 small rubber elbows that make the corner around the left front corner of the cylinder head have been know to "weep" a little fuel, not enough to call it a leak, but enough to give you a strong raw diesel odor.
I had to replace both elbows (pressure line and return line) and used the aftermarket Dorman fuel injection clamps.
Sometimes they leak just a little when temps are cool/cold, and then they seal up when the cylinder head temps comes up.
Hope this helps,
Roger
 

Paul_E_D

Member
Ah, does one of them come out from under the injector cover? Because I did notice an elbow there that had a minor amount of wetness.
 

sailquik

Well-known member
Paul,
I may appear that it goes under the injector cover, but it's been a long time since I looked at an OM-647.
As I recall, there are steel fuel lines running into and out of the 2 very short rubber elbows.
They are there to turn the corner around a sharp edge where the manifold side of the head ends and the front of the
head starts. They also absorb vibration.
If you have a small fuel line rubber elbow that looks wet, that could easily be your raw diesel odor's source.
Roger
 

220629

Well-known member
If it is a diesel smell that goes away after the engine heats up...

That is the classic symptom of the high pressure fuel pump fasteners loosening. Your OM647 engine has some history of that happening.

Search in T1N section for "tech alert fuel pump" with abittenbinder as member name. That should provide the detail that you need if loose fasteners are your problem.

vic
 
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surlyoldbill

Well-known member
Yeah, what Vic said. Open the hood before you first start it in the morning, and immediately after starting go and inspect the area around the HP pump. Mine was dripping fuel on the serpentine belt, but would stop once the engine warmed up. I think OM612 and OM647 have the same HP pump.
 

220629

Well-known member
... I think OM612 and OM647 have the same HP pump.
The pumps look similar, but are different in design. The OM612 (NAS aka NAFTA 2001 - 2003 MY) pumps have some history of seals leaking. The OM647 (NAS aka NAFTA 2004 - 2006 MY) seem to have pretty good seals, but the fasteners have that tendency to loosen over time.

Most times just re-torquing the OM647 fasteners cures the leaks. A leaking OM612 pump more often requires seal replacement/rebuild. Doktor A sells OM612 rebuilt pumps with exchange.

vic
 

MercedesGenIn

Mercedes-Benz Resource
Hi there,
I would just get a union spanner on those injector supply pipes, give em a tweak! especially the one in the middle picture on the left - isn't that wet with diesel? What does inside the lid/cover give away, anything? Anything present in the way of diesel oil marking/splatter?

All the best
Steve
 
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Paul_E_D

Member
The inside of the lid is clean, but you are right about that middle injector pipe. My plan is to put a wrench on everything in the neighborhood of the injectors. I guess I was looking for one really obvious thing, but maybe it's just a few little leaks.
 

220629

Well-known member
The inside of the lid is clean, but you are right about that middle injector pipe. My plan is to put a wrench on everything in the neighborhood of the injectors. I guess I was looking for one really obvious thing, but maybe it's just a few little leaks.
It is recommended that 2 wrenches are used on the high pressure fittings. The backup wrench helps to avoid disturbing the seal on the "permanent" injector body fitting.

:2cents: vic
 

Paul_E_D

Member
Thanks, that is why I didn't touch it in the first place. But I will hold the bottom fitting while I tighten the top one.
 

Paul_E_D

Member
Struck out. Elbows look good. no signs of leakage. and I couldn't tighten that injector fitting at all, so not loose. I'm afraid I just have a slightly leaky injector.
 

312d

Member
check also wiring harness inside the cabin, some sensors attached to the fuel system can draw fuel using the wires, i was told about this case once, on a OM611 extremely rare failure, but happened.
 

surlyoldbill

Well-known member
You'd probably see it, but the return fuel line that plugs in to the top of each injector has crappy plastic (OEM) fittings that get brittle and break, or crack, when they are handled too much. Replacement line from EuropartsSD has METAL fittings.
 

MikeHowe

2003 Sprinter 413 CDi
Hi - Your problem may not be the same as mine but the link below describes how a significant amount of raw fuel was leaking and upwelling from one of my injectors. I tested all pipes and linkages before concluding where the fuel must be coming from. The injector was refurbished and the problem stopped. Good luck, Mike

https://sprinter-source.com/forums/showthread.php?t=28530
 

MercedesGenIn

Mercedes-Benz Resource
Hi Paul,
Ok on the supply pipe union not tightening, looking good, but that looks like wetness on that joint. If you first backed off the top nut, then tightened / checked the fitting into the injector body, then 'backed' that one with the spanner and re-did the pipe union up top, then both the seal into the injector body and the pipe union would be covered.

You may have already done this, if so ignore me! :)

All the best
Steve
 

Paul_E_D

Member
Hi Paul,
Ok on the supply pipe union not tightening, looking good, but that looks like wetness on that joint. If you first backed off the top nut, then tightened / checked the fitting into the injector body, then 'backed' that one with the spanner and re-did the pipe union up top, then both the seal into the injector body and the pipe union would be covered.

You may have already done this, if so ignore me! :)

All the best
Steve
I wasn't able to budge the connection with my 13mm 14mm crescent wrenches, so no. I didn't do that. I intended to. Bit i didn't want to force the issue. It definitely a little wet there. So perhaps i should find the right tools and try what you suggest
 

Paul_E_D

Member
I'm moving on to the fuel tank. I can smell the diesel under the van, and I noticed some wetness on the tank. Sending unit or vent hose are the suspects.
 

Paul_E_D

Member
Just a follow up. I have not found any significant fuel leakage. I did replace a bad camshaft sensor and the smell seems to be gone. Coincidence?
 

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