dhonn311

hello all. i just got my 130000 original mile 93 4.0 zj last week. i noticed a couple days after i bought it that i had oil smoke coming out pf the tailpipe. the truck has a ton of power and only does this at idle. i pulled the intake pipe and flipped the butterfly open and the tb has oil resindue all in it.replaced a pinched ccv tube in the back, inlet and im hoping thats what caused the buildup. im planning on pulling the manifold and doing a new gasket at cleaning tb and manifold while its off. the truck runs too good to be rings i hope anyway. any ideas anyone has on this would be greatly appreciates as i planned on the purchasing the rough country 3.5 lift this week and some 31's. if i have to rebuild an engine it def gonna rain on that parade!

KF2M

You say it does it only at idle. Does the XJ produce smoke during acceleration (valve seals), or deceleration (rings). If you're finding residue in the intake it does sound like a case of blow by (rings). Try doing a compression test on each of the cylinders to confirm.

dhonn311

ok i took the intake manifold off this morning and all of the intake ports are equally nasty. if it were rings would it not be that one was worse than the other port? im gonna replace the intake gasket today, , did see some wet oil on the face of the gasket as well,, then do the compression test.ill post results as soon as i get em.!

dave1123

Change the PCV valve. Chances are it's sucking oil at high vaccuum at idle. Also check to make sure the oil drains in the head are clear. Only 130K on a 93 seems like it sat for a while. Could be sludged up in the valve area.

Bustedback

The oil you seen on the intake gasket could be from a leaky valve cover. The intake will look grungy even if there is not an oil consumption problem, it's fuel vapor and carbon cause that ugly stuff. Replace the CCV valve and make sure the head isn't full of sludge.

dhonn311

kool,, thanks for this insight! ready to get the lift on and hit some of these ms backwoods!