white smoke out of exhaust

[buck_hunter]

Hi everybody. I have been working on my MJ for a few months now and one thing ive been noticing is the white smoke coming out of the exhaust along with the rough idle. i just replaced my O2 sensor and that helped quite a bit with the idle and a little bit with the smoke. I am wondering if it might be something to do with the fuel injection, but idk. I have also done the C101 connector cleaning. btw it is a 1987 comanche with a 4.0. Any help will be nice thank you!

[Boots]

Try cleaning the IAC motor, it helped alot with mine. A quick search should show you were it is and how to clean it. If not, post back... :wrench:

[airspeed]

Not sure what conditions when you see smoke. Big puff at startup or while driving?

 

A big puff at startup could be valve guide seals. White smoke while idling and driving could mean water/antifreeze, possible head gasket leak...

[Jeep Driver]

Not sure what conditions when you see smoke. Big puff at startup or while driving?

 

A big puff at startup could be valve guide seals. White smoke while idling and driving could mean water/antifreeze, possible head gasket leak...

 

 

 

Pull your spark plugs and examine.

[mvusse]

I agree with the head gasket, although it could also be the intake manifold gasket. White smoke is usually antifreeze, which should not be in the exhaust at all.

 

Excess gas or oil usually cause blue smoke.

[buck_hunter]

It idles fine and i don't notice much of anything when at a idle, i notice it when i give quite a bit of gas it'll smoke then stop when i let off the gas.

[AMCJeepMJ]

This is how I learned it back in the day:

 

Blue smoke = oil

Black smoke = running rich [or a diesel]

White smoke that lingers = Coolant

White smoke that quickly disappears = Steam

[carnuck]

This is how to look at it: Are any liquids going down? (engine oil, antifreeze, excessive fuel consumption) If not, then it's nothing to worry about. There is a LOT of moisture in fuel, especially where they put alcohol in.