eyebuzz

Hello,

1987 300TDT. The om603 starts right up but when cold (engine cold not outside temp) will hesitate a bit sometimes - not every take off from a stop, but will at some point every time the engine is not warmed up (hitting the pedal but not really going - not much rpms). It recovers quickly though. When the engine is up to full operating temp there is no issue. Also when it does stumble/hesitate a bit of smoke out the tail pipe (hard to tell if it's black or blue - but not white).

I'll be introducing myself properly with some photos (probably in the w124 section) soon.

Thanks - TT

ImInPA

Have you checked the intake pathways? I have seen them get pretty blocked up with soot. I would check that and also, run a bottle of Power Service Diesel Kleen through it (gray bottle). That will clean out the fuel system and bump the Cetane up slightly.

eyebuzz

Thanks. By air intake pathways do you mean the larger metal object with the six arms going over the top of the engine? If so, looks pretty straight forward to remove - anything I should look out for in removing it? What's the best way to clean it - some solvent or just scrap it out? Thanks again.

dougiebear

Good call with the soot in the intakes.....are you using a 5W synthetic oil as well. Some diesels have an enrichment of fuel mix for startup this could perhaps cause a burp in drivability too.

Carsy

Glow plugs ?.

In some engines the glow plugs are still active for a period after starting to improve drivability & lower emisions.

eyebuzz

Thanks for the replies so far - glow plugs where recently replaced by PO (plus it starts right up after the glow plug light goes off). Didn't get the chance this weekend to clean out the intake - but I'll keep you posted.

Also, seems like a fair amount of exhaust at start up and extra poof of exhaust right after it hesitates (unburned fuel). Having not had a diesel maybe the exhaust at start up (smells like diesel not oil burning) is normal - but I'm sure the extra poof after the hesitation is directly related to my problem.

TT

eyebuzz

...also - no not using 5w synthetic. Not sure the weight - but using conventional oil.

eyebuzz

I should revise my claim of "definitely not white smoke" - well on closer inspection is kind of light/white - but has a strong diesel smell (not coolant) - I'm guessing unburnt fuel. Haven't done an official MPG test.