transam5.7lt1

iTrader: (18)

Well, I replaced oxygen sensors, I scanned my car and it shows nothing wrong, but if I give a quick rev up to about 3,500 rpms, I see black smoke out the exhaust. Its been this way since I have owned the car. I also got a new msd opti cap and rotor, new timing chain and gears installed. Car used to indicate bad o2 sensors, they were replaced, codes erased, its been 3 weeks since I did the work and still can't get rid of the smoke. Could it be bad spark? I have Autolites 104, msd6al, brand new wires. Car idles well, doesn't backfire, I've run it up to shift at 6,000 rpms and it runs great.... my only concern is that black smoke........

transam5.7lt1

iTrader: (18)

Could it be the pollution pump not working as it should? Does it have anything to do with it....? Thanks in advance for any help.

Schweet97Z

iTrader: (35)

black smoke usually means running rich, which isnt a real bad thing. its better to run alittle rich than too lean. what mods do you have? do you have a tune? if its running fine i wouldnt be too worried about it.

transam5.7lt1

iTrader: (18)

Running fine, I guess all it needs its just a little playing with a programmer.... or send my pcm to get it program.....
Not that many mods, just headers, y pipe, flowmaster, no cats, k&n intake, air foil, aluminum throttle elbow, msd6al, msd's opti cap and rotor, rebuilt tranny.

Schweet97Z

iTrader: (35)

yea get a tune!

transam5.7lt1

iTrader: (18)

Duh!.... right?

Schweet97Z

iTrader: (35)

mmmhmmm

Renegade

iTrader: (1)

I second the tune, espically since you have Headers, are they LT's? If so, a tune is usually a must in my opinion.

95formulalt1

iTrader: (13)

r old work truck use to blow out black smoke.....turmed it was buring oil!!!....but the truck ran like **** too

transam5.7lt1

iTrader: (18)

I know its not burning oil. I gues its a matter of tune.

BizZzatch350

iTrader: (33)

I wouldnt worry about it

borninatransam

iTrader: (4)

i had the same problem with mine before i got in the wreck. it would run real rich at low rpm's and blow black smoke or if i floored it. once it go to about 4000 rpms the problem would stop. i had basically the same mods as you with the exception of the new opti. i think once you get the exhaust and stuff it screws the pcm up a little and makes it run richer.

roSSco

I found this thread on a search for black smoke. Mine has been running rich ever since I put it together. I swapped out what I think are 30# injectors for stock and it's a little better, but still smokes a lot while driving.

Mods are AFR 190's, LT's, LT4 intake and ORY. Do ya think a tune will get me going?

LT1 Guy

If your car is running fine and your experiencing no problems and you only get the black smoke when you rev the engine into high rpms, it could just be a build up of soot blowing out of the exhaust pipes. Someone had to have the car running rich for quite a while. You can either wait until the soot clears out or just replace your pipes.