Bmw e34 540i White smoke when warm. Please Read

[oliverd642]

Hey all! I'm writing this on behalf of a friend concerning his e34 540i

I will try to be as detailed as possible.

Info

The car is from 92, all original with 290,000kms on the clock. Last year it failed on the emissions before being put in the garage over winter. o2 sensors are new as are spark plugs, oil and filter. The OSV/PCV looked to be in good shape, I think it was replaced if I remember rightly, anyway, an Oil catch can setup has since been installed.

Now some detail's about the problem.

The car runs good, the idle is fine, no fluctuations or anything as such. When it gets up to temperature the exhaust starts smoking white, especially noticeable under moderate to hard acceleration and the fumes smell strongly of petrol, he also said that the MPG has considerably shot up. For example: 34L of petrol would last two weeks+ but has gone to lasting just one week under the same driving conditions. Just to add, the injector seals are all new. The car is not losing any Oil Or coolant

Prior to this problem the owner had always used Castrol Edge 10w60 engine oil and never had any problems over the past 10+ years. The last oil change was Castrol Magnatec 5w40.

The car has been very well taken care of, always serviced, counter-less parts have been replaced.

If anyone could please give me an insight of what the problem could be it will be greatly appreciated!

Thanks in advanced!!

P.s. If anymore info is needed here just tell me and I will get as much as I can.

[kouks]

So it runs good, is not losing oil or coolant, but smokes. Is it a huge cloud of smoke, or just small puffs of smoke? a Huge plume suggests a head gasket failure. Small puffs suggest unburned fuel exiting the engine.

[ross1]

Testing the coolant temp sender seems a good idea, perhaps the DME is seeing a cold engine and ordering an overly rich mixture. Fuel pressure would be my next check.

[oliverd642]

So it runs good, is not losing oil or coolant, but smokes. Is it a huge cloud of smoke, or just small puffs of smoke? a Huge plume suggests a head gasket failure. Small puffs suggest unburned fuel exiting the engine.

Just puffs of smoke, occasionally get larger amount/could of smoke under hard acceleration.

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Testing the coolant temp sender seems a good idea, perhaps the DME is seeing a cold engine and ordering an overly rich mixture. Fuel pressure would be my next check.

Good suggestion thank you! But if the coolant sensor was acting up wouldn't the temprature guage be all over the place?

[Kannackas]

Alla 540 är väl importerade och då ska väl inte dessa vara bundna till avgaskrav, tänkte att du skrev om att den inte gått genom besiktning? Min 540 fick extra papper där det stod så tillsammans med sitt reggbevis.. Kanske onödigt att påpeka när det inte är relevant för era problem med bilen men bara en tanke som slog mig.

(Sorry for not using english).

[Fred39]

Just puffs of smoke, occasionally get larger amount/could of smoke under hard acceleration.

So it's probably not a water in fuel system. There would be plenty of smoke.