Sudden smoky, shaky idle

[bgkast]

My car has suddenly developed a smoky, shaky idle. I have the old style rack damper pin which I have pulled out and tested (it is marginal) which could explain the shakes, but I don't see how it could be causing the smoke. The smoke is blue-grey and is present at idle. Acceleration after idling (such as accelerating away from a stop light) causes a large plume. A few days before the smoke started I installed my air/water intercooler which required the turbo compressor housing to be rotated about 90 degrees. Other than that the only recent change was filling up with a few gallons of diesel at a new station, however those few gallons have now been diluted by B99.

What could be the cause? Turbo seals?

Thanks.

[DieselAddict]

That would be my guess. Sounds like you're consuming oil.

[bgkast]

Can they go bad suddenly? I switched to synthetic about 2 weeks ago. Could that have lead to the problem?

[compress ignite]

The synthetic will not cause the problem...BUT if excess clearances exist the
synthetic will find them.
Switching to SYN will clean out the old carbonized "coke" in the turbo bearing
chamber over time.

[Brian Carlton]

I agree........if you are suddenly making a bit of smoke at idle and the huge clouds of smoke when you open the rack........that's turbo seals for sure.

The '87 did the exact same thing.

But, it was a completely destroyed turbo on that engine.......the seals were long gone on that turbo.

[bgkast]

Originally Posted by compress ignite

The synthetic will not cause the problem...BUT if excess clearances exist the
synthetic will find them.
Switching to SYN will clean out the old carbonized "coke" in the turbo bearing
chamber over time.

That's what I was thinking. I'll pull the tubing after the turbo and look for signs of oil. It can either leak in the compressor or turbine right? Any good DIY turbo rebuild articles.

Maybe I should throw in a VNT.

[bgkast]

I have found a turbo with 30K miles on it for $100. I guess I play with a few other things and then buy that. Any chance that the intercooler could have lessened the air flow at idle causing over fueling? Should I try backing off my ALDA.

[GRIESL]

Originally Posted by Brian Carlton

I agree........if you are suddenly making a bit of smoke at idle and the huge clouds of smoke when you open the rack........that's turbo seals for sure.

The '87 did the exact same thing.

But, it was a completely destroyed turbo on that engine.......the seals were long gone on that turbo.

I remember reading that bad turbo seals would cause the oil to pool up and wait til the throttle gets goosed, at which time it'd get sucked in and cause a plume at takeoff. So can bad turbo seals cause smoke at idle as well?

[Brian Carlton]

Originally Posted by GRIESL

I remember reading that bad turbo seals would cause the oil to pool up and wait til the throttle gets goosed, at which time it'd get sucked in and cause a plume at takeoff. So can bad turbo seals cause smoke at idle as well?

Of course it might have some wisps of white smoke at idle, but nothing serious because the oil can't rise up into the manifold........airflow is too low.

[bgkast]

That is how it acts. Once I am up to speed It either stops smoking or I can not see it because it is being dispersed.

[Brian Carlton]

Originally Posted by bgkast

............ or I can not see it because it is being dispersed.

.........that's it.......

[bgkast]

Anything else I should try before I buy a new turbo?

[Brian Carlton]

Originally Posted by bgkast

Anything else I should try before I buy a new turbo?

Disconnect the turbo from the intake manifold and look for oil at the outlet from the impeller and oil coating the walls leading to the intake manifold. It's difficult to guide you here because some oil is normal, but a heavy coating of oil and any droplets of oil is not.

Disconnect the breather hose from the top of the valve cover. Observe if the blowby situation has changed for the worse in any way.

[bgkast]

Already checked the blow by; it is unchanged. I'll take pull off a silicone boot from my intercooler and check for oil Monday (I’m out of town for the weekend). Is there any chance it could be leaking into the turbine rather than the compressor?

Oh yes. Just check your tail pipe for liquid oil or separate your downpipe from the turbo. Have you measured the actual oil consumption yet?