So I've bought my first merc, I have a C220 CDI , 2001 registered, on hard acceleration there is always a puff of smoke. I can notice this only in the dark - but I'm sure it happens in the day also only I can't see it in the rear view mirror. Is this common ?
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smoke from exhaust
- Thread starter casman
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dieselman
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It's normal. 220 CDis are not the cleanest diesels on the market, nor the dirtiest, VW take the crown on that one.
The engine will fuel up slightly before the turbo boosts so you see a small amount of overfuelling.
You will always see smoke at night, but shouldn't in the day.
The engine will fuel up slightly before the turbo boosts so you see a small amount of overfuelling.
You will always see smoke at night, but shouldn't in the day.
Smokin'
Well my E300TD smokes a fair bit under moderate acceleration when cold and under hard acceleration when hot. It's not oil smoke (thankfully) but looks like masssive overfuelling. I was wondering if MAF sensor problems could cause this. Our Vectra TDi had a MAF sensor failure at 37k which resulted in surging under full throtlle and general lack lustre performance. I was told it (MAF failure on all cars) was very common. The engine diagnostics didn't detect the failure on the Vectra and I doubt it will do it on the MB. I odn't fancy swapping it just for the sake of it - it's £170!!!! Any comments anyone
Well my E300TD smokes a fair bit under moderate acceleration when cold and under hard acceleration when hot. It's not oil smoke (thankfully) but looks like masssive overfuelling. I was wondering if MAF sensor problems could cause this. Our Vectra TDi had a MAF sensor failure at 37k which resulted in surging under full throtlle and general lack lustre performance. I was told it (MAF failure on all cars) was very common. The engine diagnostics didn't detect the failure on the Vectra and I doubt it will do it on the MB. I odn't fancy swapping it just for the sake of it - it's £170!!!! Any comments anyone
dieselman
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It could be the MAF, but first check all other avenues.
Is the EGR valve stuck open, is the inlet manifold restricted by EGR filth, is the turbo blowing to at least 1Bar, are any injectors partially blocked or dribbling, is the timing properly set?
The MAF can easily be checked on the Star Diagnostics against the design peramaters, but not many techs know how. :?
Simply rev the engine and compare the actual values against the stored ones.
You can measure the MAF output with a Meter at the ECU. The readings start at about 2v at idle and rise as the amount of injested air rises. I believe max output should be about 4.5v.
Is the EGR valve stuck open, is the inlet manifold restricted by EGR filth, is the turbo blowing to at least 1Bar, are any injectors partially blocked or dribbling, is the timing properly set?
The MAF can easily be checked on the Star Diagnostics against the design peramaters, but not many techs know how. :?
Simply rev the engine and compare the actual values against the stored ones.
You can measure the MAF output with a Meter at the ECU. The readings start at about 2v at idle and rise as the amount of injested air rises. I believe max output should be about 4.5v.
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