Truck Smoking on Deceleration?? HELP!!!!
 

Hey guys,

Im posting this for a friend. He has the same truck as me but its a 97: Dakota with the 318 v8.

He removed his catlytic converter and his truck now smokes (out of the tailpipe) on deceleration only. The color of the smoke is a bluish gray color. It doesnt smoke any other time, only during deceleration or downshifting.

One mechanic told him it was only because he removed the cat and that it was normal.

Another one just told him he had bad rings.

Any ideas?? Any help will be appreciated.

blue normally indicates oil... hmm..

I forgot to add..its only got 76K miles..low miles which is weird. It was running like crap and his cat converter was all broken up inside. So his mechanic said to gut the cat to make it run better. It helped a little then the crappy performace eventually went away. He assumed it was just bad gas. Now that the cat is out it smokes on decel.

have him do a compression test on it, and secondly tell him to look down through the throttle body into the intake plenum, if theres a film of oil on the bottom, thats fine, if it's flooded, theres problem #1. no check engine light?

yes check engine light is on. That came on when the truck atarted running like crap. Then the mechanic cleared the check engine code after he gutted the cat..then it came back on again. He assumed it was because of the gutted cat??

what would oil in the throttle body mean?

cel should be because of the gutted cat, look under the 2nd gen forum up top at the stick CEL and it should tell you how to retrieve that code from the truck and will define the code for you. oil in the intake can mean a bad pcv valve allowing a lot of crankcase blow by oil into the intake manifold. o and if any mechanic erases a CEL without ercording what the code was, shouldnt touch a vehicle IMO... thats very negligent of a problem.

usually when you got smoke on deaccel its your rings. Due to the engine speed on deaccel and high vacuum in the cylinder its sux the oil past the rings and burns it in the cylinder.

Blue smoke on decel. usually indicates bad valve stem seals. Could be easy fix if you can charge each cyl with air, depress valve spring to remnove keepers, remove spring and replace the seal. Would be easier to replace with heads removed, though. And if you are going to the trouble to remove heads, might as well build heads.
If it was the rings, it would smoke blue all the time.

i would do a wet and dry compression test and go from there.