C320 cdi OM642 sometimes loses boost

[Cooper645]

Can someone give me a pointer to where this fuse 44 might be?

so all fitted and egr valve cleaned (wasn’t too bad to be fair)

car works well again, i ran the live data and did a fault code check

only getting one code now (a new one)

P1268(00) {I have previously had cylinder 3 glow plug replaced about 18 months back.}

anyone give me a pointer or a clue?

 

[Wighty]

Can someone give me a pointer to where this fuse 44 might be?

so all fitted and egr valve cleaned (wasn’t too bad to be fair)

car works well again, i ran the live data and did a fault code check

only getting one code now (a new one)

P1268(00) {I have previously had cylinder 3 glow plug replaced about 18 months back.}

anyone give me a pointer or a clue?

On my om642 E class , it’s engine bay , back left as you face the engine , behind the brake fluid reservoir (which is under a drain cover ) . Fuse 44 on mine is back right of that fuse holder

 

[Cooper645]

Thanks, I’ve checked all the fuses in there and they’re all fine.

just this P1268 code to chase down now.

Have attached images of the EGR valve before and after.

 

[Cooper645]

You would be better off getting the actuator refurbed if you cannot match the numbers to the turbo, a s/hand one may not be the correct type for that turbo. Or get in touch with Carwoods and see if they can refurb or supply the correct actuator for that turbo.

Bought a refurbished one from www.turbovanes.com and I would highly recommend them to anyone having actuator issues.

 

[Cooper645]

How is this P1268 - Cylinder #8 High To Low Side Short

possible on a V6?

#Confused

 

[LostKiwi]

Quite possible if you aren't using a Mercedes specific code reader.
Generic codes do not always map correctly to MB specific codes.

 

[Cooper645]

Well it never came up on a mates reader today so that’s all good.

the car did cut out with the below condition on an Italian tube drive home.

P0234 - Engine boost condition - limit exceeded

it was past the motorway speed limit - so I can’t help thinking there’s still a problem somewhere.

Any guesses? I can’t think of anything else to check to be honest

 

[Wighty]

Well it never came up on a mates reader today so that’s all good.

the car did cut out with the below condition on an Italian tube drive home.

P0234 - Engine boost condition - limit exceeded

it was past the motorway speed limit - so I can’t help thinking there’s still a problem somewhere.

Any guesses? I can’t think of anything else to check to be honest

Total guess , but free job , clean out the underside small pin hole in the exhaust back pressure sensor with carb cleaner ( just left of the egr and right of the turbo )

 

[Cooper645]

I’ll try anything, and as it’s free there’s nothing to lose. Cheers for the suggestions.
I may also try and get some smoke for a Vacuum leak test too.

 

[DimiV]

I’ll try anything, and as it’s free there’s nothing to lose. Cheers for the suggestions.
I may also try and get some smoke for a Vacuum leak test too.

Sorry for resurrecting an old thread, but just curious if Cooper645 managed to resolve the issue finally? I'm currently chasing the exact same thing down on my car which is exactly the same model and year.

 

[Cooper645]

The main thing that worked for me was the boost hose which had cracks in and the replacement actuator from turbovanes. (After this failed almost catastrophically)

Feel free to post up here if you find anything else relating to the matter.

I have suffered the over boost twice since then, but only at far too fast speeds, so consider the issue resolved enough for me. (I suspect another small leak in the boost line somewhere considering the amount asked of the engine when it fails [going to top end in final gearing])

 

[mioba]

Had exactly the same issuea on my R Class. the actuator and the large turbo hose were both goosed.
Actuator leading to limp mode and loss of turbo.
Hose leading to running lean.
The actuators (Hella) Have the numbers stamped on them and make sure you get the correct no as they are coded to the car.
Took me about 2 hours to replace mine as working from behind with limited space. Most important is not to loose the cir-clip that goes on the actuator arm. loads of vids on youtube om642 actuator replacemt.

the metal turbo return hose also has a little grean seal in that is prone to break.

 

[DimiV]

Thanks for the replies guys! I did actually manage to find the cause of mine, it subsequently made itself rather obvious to the naked eye.
The hose exiting my intercooler developed visible cracks. At this point the car couldn’t go more than 2-300m before losing boost. Swapped it out and been running perfect since.

 

[Cooper645]

Glad you're all sorted