Excessive Smoke

[Musada]

Have a 1990 Ls 400 with 120k miles

When i'm on the highway and i'm going around 60-80mph, as soon as it shifts into the last gear while i'm accelerating hard an overwhelming amount of excessive smoke starts pouring out of my exhaust. The car doesn't run any different. But it always does it. Anyone know what the problem could be?

[VBdenny]

Mine did the same thing a couple of times and it turned out to be power steering fluid getting sucked in to the vacuum on the intake manifold. Yeah, I probably should have replaced the control valve thing on the PS pump but, I just blocked off the 2 vacuum lines and everything including the white smoke at start up sometimes, to return to normal. I see you also have a 90 and it's just old stuff and when you get on it, old stuff smokes sometimes. Measure the enjoyment against the fluid lost and you'll be okay.

[Musada]

Mine did the same thing a couple of times and it turned out to be power steering fluid getting sucked in to the vacuum on the intake manifold. Yeah, I probably should have replaced the control valve thing on the PS pump but, I just blocked off the 2 vacuum lines and everything including the white smoke at start up sometimes, to return to normal. I see you also have a 90 and it's just old stuff and when you get on it, old stuff smokes sometimes. Measure the enjoyment against the fluid lost and you'll be okay.

Well i know its not the power steering, the valves went out months ago, and i havent put in PS fluid in it since.

[RDM]

There could still be a large amount of fluid inside the intake, as soon as it begins leaking there's constant leakage into the plenum that saturates the entire intake, even if you disconnect the PS system. When the throttle opens the vacuum from the engine can wick the fluid through and into the combustion chambers.