White Smoke and power loss.

Thats a new one on me, I cant really see how lift pump failure would cause white smoke, anyone care to explain?

Ive had the lift pump die a few times on my 200 and only thing I ever noticed was slight lack of power at higher rpms.

lynall said:

Thats a new one on me, I cant really see how lift pump failure would cause white smoke, anyone care to explain?

Ive had the lift pump die a few times on my 200 and only thing I ever noticed was slight lack of power at higher rpms.

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I don’t know why it smokes when it fails. But it doesn’t do it every time. I have had a few fail and only one fo them smoked when it failed. Normally as you say it is a lack of power at high revs or the lack of ability to rev high.

dag019 said:

I don’t know why it smokes when it fails. But it doesn’t do it every time. I have had a few fail and only one fo them smoked when it failed. Normally as you say it is a lack of power at high revs or the lack of ability to rev high.

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In the end I got sick of them so stuck a facet on and its been fine ever since.
If you get one fail again causing white smoke it would be interesting if you could cut it open and see whats going on.

My thoughts are that a lift pump sometimes doesn't fail completely, so 'some' fuel gets through, but not enough for power or speed .. therefore less fuel and more air in the mixture equals white smoke ...

Perhaps with a weaker mixture one cylinder that may be a little down on compression stops fireing before the others and produces white smoke.

tottot said:

Perhaps with a weaker mixture one cylinder that may be a little down on compression stops fireing before the others and produces white smoke.

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That makes sense but then surely you would feel the engine misfiring, which is very distinctive.

White smoke means unburned fuel vapour which means either low compression (not getting hot enough) or poor atomisation so its in drops and not igniting, same for a very cold engine - its too cold to burn. If the lift pump has failed in a way that lets air in then the air compresses in the HP lines and injectors and stops the hard/fast atomisation so the fuel injection is poor. Not all pumps will fail this way, its the same reason you get white smoke when bleeding the fuel.