Mechanical Problems & Technical Chat - 95 ex has black smoke coming out

Hey,

I have a 95 ex coupe auto (its my girls), and it has black smoke coming out the exhaust. I took it to the mechanic once and he told me that it could be the head gasket. I replaced the head gasket and the black smoke is still coming out. Anyone know what this could be?

Thanks for your thoughts and comments.

-Damian

Did you replace the head gasket seal or use the old one?

I replaced the seal also. Do you know if it could be the piston rings or so? The car has like 220k on it! Do you know of any backyard mechanics in or around LA (90005)

Black smoke indicates a rich condition - it should smell kinda gassy too.

When you had the head off, how did the pistons and the underside of the combustion chambers look? If they were pretty blackened, then you've got some major carbon build-up, most likely from the rich condition.

I would try running some Sea-Foam through it and see what happens next. Fire up the car, let it get to operating temp, then pull the power brake booster vacuum line (from the booster side) then carefully pour about half or 2/3 of the can of Sea-Foam into it - then shut it off. Pour the last of the Sea-Foam into the gas tank. Let it sit for about 15 minutes, then fire it up again and let it run. Be prepared - it's going to smoke like a mofo for about 20 minutes - nice light-grayish colored smoke, too. Skeeters won't be a problem for a day or two.

If it's still smoking black after that, this will be a good time to change the plugs as well. If your spark plug gaps are too far out, it might not be completely burning the gas, which just turns into more carbon and sent out the back end. When's the last time the air filter, distributor cap & rotor, and spark plug wires were changed? Weak sparks can cause a rich condition too.

I'm not saying this will fix the problem for sure - but it's the cheap place to start. Make sure you Sea-Foam it before changing out the plugs though - because the Sea-Foam might actually make them worse if they're in bad shape.

SEA-FOAM FTW!!

id also check the oil level... if its burning oil.... some times in my old impala its burning oil looked black....

hows its performance? does it seem to lag when ya punch the gas pedal? and smoke only when ya stomp the pedal?

id also run a compresion check...

hmmm.....maybe I'll just get a new motor or sell the whip!
thanx for the input though..

When is the last time the PCV valve/02 sensor was changed? Those are cheap fixs'.

good question.............i'm not sure.....how do i replace the pcv valve anyway?

Pull it out and put on a new one. Its simple. Get a haynes manual. Youll be glad you did.,

Where is the PCV valve?

i believe its right behind the intake manifold..... best to buy a manual on the car.... they are preaty cheap and have TONS of stuff that you would realy like to know!!!! ya never know when a simple book can save your @ss...

but with selling the wip...... why it just needs a tune up..... at least TRY first unless the car is total crap and ya dont want it anyways.......

im sure someone will know whats wrong with it by looking at it and save money on the car and fix it thierselves...

Black smoke is from too much fuel- main cause= fuel injectors, o2 sensor reading bad,pcv like they said.or sometimes fuel pressure regulator
Blue smoke is from oil burning- main cause= rings, or valves
White smoke is from coolant leak into cylinders- main cause= head gasket
if it looks black, look when the sun hits the smoke- it may be a dark blue and thats how u kno it is from oil burning in the cylinders.
that mechanic should of told u that, oh, does it smoke all the time or when u hit the gas??
hope that helps