TonsFun

Hi there,

well i have a 1999 Grand Cherokee limited 4.7L (i guess) AWD?

well i recently bought this GC for 2000$ in extremely good condition inside and out, it has 214K miles on it, and i have had a Cherokee back in Highschool with more mile on it than that... but here is my question..

during the first of the morning start up starts just fine, after i reach operating temp, i will get a puff of smoke if i take of from a Stop light to fast, and if i drive around town then stop and go into a store and come back out i get a puff of smoke when i start it

just to clafiy
NO smoke on cold start up
NO smokeon first drive (before reaching op temp)

will smoke -
after reaching operating Temp
starting the Jeep after it been running for awhile
upon taking off from a stop light (but not while getting on the freeway)
Lite Lite smoke while idling
good Puff if in park and reving the engine

There is no Light on in the dash, Itruns very smoothly

I have put my hand near the tail pipe to try and see if i can smell the exhaust, No Sweet smell, No Oil smell, it kinda smell like gas...

any thoughts that can help let me know thanks

onlyinajeep726

What kind of gas mileage are you currently getting? If it smells of gas, it's running too rich, which points to O2 sensor or MAP sensor. That's where I'd start.

TonsFun

hmm actually never really checked, i have probably done about 60miles on a 1/4 tank of gas

dave1123

That's 5 gals in 60 miles? Do the math! Not good, but not terrible. It might be a leaking injector.

TonsFun

OK I have checked on my mileage.... According to my info center (that screen up near my map lights) I am doing an average of 14.4 miles to the gallon... I started it up after work yesturday and I thought I saw blueish smoke... Then I knew.. Either stem seals or rings...

dave1123

You know, GM small blocks have a habit if sludging up the head oil drains. That holds oil about the exhaust valve stem seals and leaks down into the cylinders after shutdown. In extreme cases, it will build up to make the engine smoke during all running, even missfireing and smoking like a chicken BBQ. On that one, we took the valve covers off and about a quart of oil poured out!

The fuel mileage is about right. To be exact, you'll have to do the fill and record trick.

Pull your valve covers and clean out the drains. On a Chevy, they are only about 3/8 " holes in the corners of the heads.