1995 Pontiac Grand Am black smoke and oil on piston

IBMALOR

MEMBER
1995 PONTIAC GRAND AM
4 CYL
2WD
AUTOMATIC
115,000 MILES

The question I have is if you would happen to know why black smoke is comming out my exahaust and the vehicle idles rough but when you go to move it it starts out really rough and you have to give a lot of gas to get anywhere misses real bad and I had removed spark plugs to check for oil on the back to see if that was the problem and there is oil on the back of spark plug 1 do you have any ideas or suggestions I was thinking piston rings but that is a costly process and want to have a better understanding of what is going on before I go through that kind of trouble thanks

Monday, January 5th, 2009 AT 1:14 AM

1 Reply

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

Black smoke is fuel fouling and if the plug is wet you may have a faulty plug, lead or leaking injector. You can do a wet comp test to prove the rings, that is do a normal test a and then add a small amount of engine oil to the cylinder, if the comp rises the rings are leaking if not it will be a valve problem, check this out first.

Mark (mhpautos)

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Monday, January 5th, 2009 AT 1:57 AM