95 Q45, smoke out the tailpipe....

[mista808]

its not constant. when i drive normally, or at idle, nothing happens.... but when i decide to put the pedal to the metal, right around 3500rpm or around where the VVTi (or whatever infiniti calls it) kicks in, i can see what looks to be white-ish/gray-ish smoke in the rear view mirror... again, only when i floor it, other than that, no smoke at anytime...

no oil in the coolant, no coolant in the oil when i changed the oil. no signs of a blown head/ no bubbling bubbles when i take the radiator cap off and let it run... possible oil leaking past the rings, but the smoke would be black-ish....

what other things should/could i check out? thanks in advance...

[mxr662]

Black smoke could be too rich. (Too much Fuel)

[qship96]

Trapped water in exhaust {condensation} being forced out due to high velocity of air moving through exhaust system at high RPM's- normal. Do several full throttle high rpm runs back to back, and I bet you see it disappear.

[maxnix]

When did you last replace VC gaskets?

[mista808]

Trapped water in exhaust {condensation} being forced out due to high velocity of air moving through exhaust system at high RPM's- normal. Do several full throttle high rpm runs back to back, and I bet you see it disappear.

i was thinking the same thing, but wouldnt it get burned off eventually from driving for a long period of time? also, ive never changed out the valve cover gaskets. it does show any signs of leaks on either side.

[goody90q45]

How's your gas mileage been lately? Have you noticed a sudden drop? A little harder to start in the morning? White smoke can also mean unburnt fuel in the exhaust....like maybe you've got a leaking injector lower o-ring. We're seeing it more often on the original injectors/o-rings on the 94-96 Q's as they age.

[maxnix]

Just a WAG that a clogged PCV valve along with a leaking VC gasket could mimic those symptoms. But if there is no oil seepage above the headers, not a good theory.

[Skibane]

Trapped water in exhaust {condensation} being forced out due to high velocity of air moving through exhaust system at high RPM's- normal. Do several full throttle high rpm runs back to back, and I bet you see it disappear.

I think you nailed it. My Y33 does the same thing, even after it's been running for a while. It usually takes two high-RPM runs to clear it out - One just isn't quite enough.

I've never seen a vehicle that produces as much exhaust condensation as my Q. At least a pint of water rolls out of the exhaust pipe when it's parked on an incline! Naturally, part of the problem is that quite a bit of my driving consists of short trips.

Rich mixture + cold exhaust pipes = condensation o-plenty.

[mista808]

Apon start up, there is no smoke. Well on my way to work, I decided to floor it, and again, smoke around 3500rpm.... I only live about 2 mins away from work so I was only able to get one good stomp out... so I sat in the parking lot, threw it in park and reved the living hell out of it, once, twice, and on the third time, no more smoke.... I did give about 3mins between revs..... but no more smoke, about 10mins after I gave it one good one, and let the rpms bounce and still no smoke.... very relieved... thanks everyone for your help, input, and experiences.....

[maxnix]

Hope you can confirm OEM OCI with the service records you procured before purchase. If not, abuse could cause premature valve guide wear, but unknown here, even on some VH41De with unknown provenance.

Keep watching and let us know. I never see water vapor except on first cold start and only slightly until warm.