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Poor cold starting, Excessive blue smoke 2006 2.0d bmw?
Had it in for a service, diagnostics showed it had 2 glow plugs down. I expected this as cold starting had got worse recently with the addition of a puff of blue smoke on cold mornings.
So 4 were ordered and replaced, with no difference over the following weeks and colder weather the problem got worse.
Now in a morning it will start for 1 second and stop, then again and again.. then it starts but wont rev up for 2/3 seconds while blue smoking like a train, then it clears and its perfect for the rest of the day.
So the glow plug control module was replaced, and again no difference.
It is not using any oil, so i assume the problem is fuel related.
Im thinking a weak fuel pump or leaking injectors.
Or could it be something else?
Its not valve stem oil seals, or it would smoke on the overrun when I took my foot of the accelerator and it would use oil which isn't happening.
2 Answers
- the_boy_toyLv 78 years agoFavorite Answer
From what I have read, blue smoke indicates burned oil.
If it's struggling at start up, I can only think the valve stem seals are leaking oil overnight and contaminating the combustion chamber. Once it gets hot enough and burns it off, it's clear and it runs decent again.
Edit:
Valve stem seals contract (shrink) when they cool down. this lets any oil that is left in the cylinder heads to leak past the valve stem seals and into the combustion chamber. Once the engine is running and hot, the valve stem seals expand and make a good seal again which prevents the oil from leaking into the combustion chamber. The amount of oil that leaks into the combustion chamber when the vehicle is sitting is minimal that's why it doesn't produce smoke for very long.
Source(s): 30 yrs home mech and Mech Eng - Michael SLv 78 years ago
I'm not positive but there should be an indicator for the glow plugs, and the car shouldn't be started until the indicator tells you to, especially on a cold weather start. It's a diesel.
If it doesn't have an indicator then you should probably turn the key to the "ON" position and leave it there for at least 10 seconds, maybe more on very cold days. The cylinders need to warm up to get good combustion.
