95 Grand Cherokee Motor Problems

[ZJjason]

I have a 95 ZJ with a inline6 4.0 97,000 miles


Problems:

1. Smokes redic at idle or full throttle. (blue)
2. Fauls plugs like no one buisness.
3. Rough idle.

Note: Truck has been over heated many times. 250degree

I think it could be time for rings or maybe valve stem seals?

Not sure if its oil burning or fuel. fuel could explain the fauled plugs but its got new cap/rotor, plugs, wires. etc. just cant figure out the problem.

Please dont respond with put a differnt motor or new motor. Some acual technical support.thanks

[BLACK RAM CTD]

If it's blue smoke then it's oil. Black smoke would be a rick condition which would be fuel. Sounds like you either have leaky valve seale or you burnt out the rings and your fouling your plugs.

Start out by doing a compression test on it. If it's reading good on all cylinders then I would say it's not the rings and look into getting the cylinder head rebuilt.

[outalne94z71]

sounds like the rings, if its been overheated like that then the cylinder walls are probably really scored or you have broken oil rings.

[ZJjason]

Any estimate on psi per cylinder?? i dont have the book...

[outalne94z71]

it should be around 125-150