Smoke diagnosis 2.25 diesel

May 07, 2007 3 Replies

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Stuart Gray 19 years ago

Getting some smoke that I want help with.

On start and cold, blue/grey smoke - this I think is oil, 'cos its using a litre every couple of weeks. I've got a new head gasket set, and will be replacing everything when I have a free day. No water loss.

Some black smoke under hard accelerator - overdieseling?

Occasional puff of black smoke when running on the level - don't know about this one. It is as though an injector suddenly pumps a bit more into one cylinder occasionally. I'm going to look at the timing when I do the gaskets, but it is using 12.5 l/100 km (about 25-27 mpg, I think) so it isn't doing too badly.

Any ideas?

Stuart

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Oily 19 years ago

Timing chain stretched slightly causing retarding of timing, either fit new chain or temporarily move injector pump slightly (clockwise IIRC) to advance timing. If you fit new chain you can also correct the valve timing as well.

Martin

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Alex 19 years ago

If it smokes badly for a little just after starting, then it's worn valve guides. New valve guide seals may help, but it's unlikely to cure the problem entirely. Oil runs down the valve guides when it's standing, and sits on top of the piston. When you start it burns the oil off.

Alex

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Bob Hobden 19 years ago

If you are going to remove the head to replace the Head gasket then check the valve guides for play and check/re-grind in the valves to ensure a good seat, but no matter what you find do replace the rubber valve stem seals as they harden and stop working in time. They cost pence. Cured the smoke on start-up on my 1986 90 petrol.

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