Lopes Idles, Black powder from exhaust (not black smoke)

[edwinelisia]

Im kinda need your expertise :boobies:
my friend has a pontiac and it has lope idle during warm up. and its spitting black powder from the exhaust. What possibly can this be ?

Thank you
E.

[kowalski]

sounds like its running incredibly rich, Did you ever get this sorted?

[edwinelisia]

Not yet, Do you know the possible source of the problem ?

[kowalski]

if its carborated, have you checked the jetting and calibration of it? could be an eff'd up carb, especially if its an old holley. I had lots of problems with those old holleys on my chevelle and the belair, they always need adjusting and tend to be really finicky and moody. i need some more details to help you out tho, what year, whether its carbed or FI, anything you can give me.

[edwinelisia]

Its FI, it has new Spark plug, 2 O2 sensors,
4 cyls, All stocks except muffler,
1 mech said its a bended valve. Engine doesnt show any sign when hot.
These all i can think right now.

[kowalski]

a bent valve would show up on a leak down test, or a compression test. also you should have ignition in all but that one cylinder assuming not enough compression.