Fiero engine problem

[ScotMac]

Hi all, I have a bit of white smoke on my Fiero. It doesn't smoke when idling, but after idling a bit, if i rev it i get a good puff of white smoke. Smaller amount if i rev after not allowing it to build up under idle.

I have done a compression check, and since it only ranges over 4 psi from low to high cylinder, i don't believe it is cracked head or head gasket. My current guess is intake manifold gasket. On the fiero based duke engine, it has a hot water passage next to the #4 runner on the intake manifold. My guess is that the intake gasket is allowing a bit of coolant into the intake.

What do you think...possible?

Thanks, -Scot

[Team SSR]

Look at yoursparkplugs. As a general engine rule for all gas engines: If water is getting into the combustion chamber that sparkplug and cumbustion chamber will be cleaner than the others. If the smoke is from oil (getting past the rings or valve guides) then the sparkplug will be black and maybe oily wet.

[joeg]

measure your coolant loss over time. Unless she is puffing a lot, I would be against a catasrophic failure.

[Rabbit07]

It has been a while since I have worked on those engines, but I recall an issue with head bolts. They stretch, break, somethings like that. The result is a blown head gasket. I also recall working on a 2.5 that had a crack running the whole length of the cylinder bore. If one of the plugs is clean, then pull it apart and look very closely at the engine.

[ScotMac]

Sorry, forgot to mention. Yes, the #1 and #3 plugs had a good amount of white on them (tho only on one side of them), which is also why i suspected coolant. But again, i don't think blown head gasket or head bolts, since the compression is perfect on every cylinder.

Oh, and i don't think it is bad enough to show much of difference in coolant level.

Hence my intake manifold gasket thinking. Any other possibilities? Even a slight head gasket problem would show up significantly enough on the compression readings, right?

[schumi]

I would go on Pennock's Fiero forum. They have a ton of experts on that engine on there.

[Team SSR]

Maybe... Cylinder pressures are obviously higher when firing. Did you do a leakdown test with compressed air or a compression test where you spin the engine over with a starter and read the gauge? With a leakdown test you may be able to hear where the air is going and may actually see air bubbles in the cooling system.