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dog man
07-10-2008, 07:41 AM
Hi Guys I posted a while ago about excessive smoking on start up..not just in the morning, even on start up after being left for an hour or so - which is a clue, if the guides were that worn as to smoke after such a short time, I would get smoke after coasting in gear and re applying the throttle - but it doesnt!?

It's a 94 540i/6 with engine replaced by bmw. The wierd thing is that the smoke does not smell of oil at all...in fact is smells like paint or diesel (I do know what burning oil smells like btw:)) Also last week it did not emit this smoke at all and now its back again.

I've done all the gaskets, pcv, oil pump etc etc

The history file shows new fuel lines earlier this year...could the garage have done something wrong there?? When it emits in the morning it usually stalls as the smoke is coming out? I know, I know you're thinking the engine is toast but it just isn't!! I've had too many cars and worked in my fathers garage for too long to know that this simply isnt a worn engine, if it were that worn it would smoke under load, this is clean as a whistle under load, plus the fact that it stalls makes me think it's fuel related...could it be a leaky injector? it's blue/black smoke..and it floats away quickly not like oil smoke which hangs in the air

Removing No8 plug reveals no real colour difference to the other plugs so I tend to rule out bore wear on that basis not to mention the fabulous performance and fuel economy, but I know there isn't a lot else that could be causing this smoke:(

Anyone have any ideas on this most strange one? P.S - the engine air temp sensor is apparently reading too hot so I'm fitting a new one tommorow...could that be related? I though maybe if the ecu was getting the mixture totally wrong then, maybe....I dunno:(

Rus
07-10-2008, 08:55 AM
A leaky injector is a likely suspect, as you mentioned. If it leaks, you'll have a very rich start up with some gray/black smoke that smells of gasoline or rotten eggs. If an injector is leaking, you will also lose fuel pressure and it'll crank over more than usual on start up. If your ECU was reading a higher than actual temperature, it wouldn't have the symptoms of a rich running engine.

Ross
07-10-2008, 09:02 AM
Agreed. You may be able to pipoint the one by using the screwdriver stethescope to hear which injector sounds soft.

dog man
07-11-2008, 04:27 PM
Cool thanks guys, have fitted the new temp sensor anyway as I knew it was reading to high.

I will check the injectors and re post! thanks again!

dog man
07-15-2008, 06:17 AM
I'm finding it a little bewildering the array of injectors on offer. I want to get a whole set but I'm unsure which ones are correct for the 4.0 M60 can anyone set me right....

cheers

Ross
07-15-2008, 08:18 AM
http://www.realoem.com/bmw/showparts.do?model=HE13&mospid=47406&btnr=13_0385&hg=13&fg=15
#7 There are also lots of places that will sonic clean, test and replace the filters and o-rings for ~$20 a throw.

dog man
07-16-2008, 05:24 AM
Thanks Ross!

dog man
08-03-2008, 05:19 AM
Okay stock injectors cleaned/reconditioned. The report? oil deposits and 'normal' wax build up. The result is it still smokes on startup but I experimented the other day - I ran her out of fuel and left her overnight. In the morning with fresh petrol it started with no smoke?

This is a strange problem:(