LS1Silverado05

iTrader: (41)

I had a run in with a local LS1 tonight...all was well, as his headlights stayed behind me....BUT I noticed that right before shifts...probably around 6,100 I saw a brief haze come from the back of my car ...seen clearly in his headlights. I could not tell the color etc...All I know is that on the top end I dumped a little puff in a couple gears. Am I in for trouble?...Or does this just happen above 6Gs on a 92,000 LT1? I have seen it while behind other guys Mustangs, LS1s and Other LT1s. Please...feed me some info on this subject?

LS1Silverado05

iTrader: (41)

A blatant bump.

omaha stylee

hmm is the car running rich???? that kinda sounds like it could be part of the problem.. did u notice that u dumped any fluids? did u pull over and check the car out after???? did it come from the exhaust or somewhere else? I remember when I blew up my stock converter it dumped all the trans fluid and when it hit the piping for the exaust I had all kinds of smoke.... but you would have noticed that for sure.......

LS1Silverado05

iTrader: (41)

No leaks or anything. My car is bone dry at every gasket underneath. Maybe its getting fat at the higher rpms? The car IS tuned for its present setup. So I would think everything is in order in that respect though.

Charging TA

Check that the dipstick is seating fine... if you do a search for my user months ago I posted a picture of how my dipstick had broken and was not sealing so it would sometimes pop out at high rpms... new dipstick fixed it.

MrCadillac

It could be sucking a bunch of oil in thru the PCV system. (The fresh air side) I know it's very common for oil to be trapted in the line on the passengers side, then at high RPMs, the oil gets sucked into the TB, and burned off. take that black hose off(the one that goes from the passengers valve cover to the TB) and see if there is oil in it. there is a 6" long low spot in that hose, and oil pools there. garentee that tub is full of oil, cuz at 92K, that LT1 shouldn't have any blow-by issues. Alot of guys at Impalassforum.com have done a modification to prevent this, by making sure there is a steady incline from the gromet, to the TB, or pluging the gromet hole, and runing the tube to the oil fill Stick in the valve cover, since it's alot harder for the oil to be forced that high up, or by pluging the TB hole, and putting a Filter on the gromet. Or, some guys run a tube from the gromet to the trans member to dump the oil, if it ends up not working.

The gromet is the 90* black tube that is on the back half of the passengers valve cover. and while your at it, replace the PCV valve on the drivers side of the intake.

Razor_Blade

iTrader: (8)

Mine does this to, but I am 99% sure that it is black smoke. IT will leave a trail the whole time I am at WOT with an extra little burst around each gear change.

I am going to check the PCV thing that MR Cadillac mentioned, because I have experienced that problem before on a second gen, but I am confident that something is causing my car to go pig rich at WOT.

I think you should go romp on your car in the daylight and have someone that you trust follow behind to identify the color of smoke.

Honda Hunter

iTrader: (8)

Mine would do it also. I was told it was normal. My stock Vette motor did it also.

slamm69

iTrader: (1)

I have the same problem.Around or above 5500 it starts leaving a black smoke trail.I also think it is running rich.But how in the hell do you stop an LT1 from running rich?My friends always tell me I'm smoking and my exhaust stinks-no cat- but atleast they are behind me.Does anyone know the cure,I know it is black smoke.

omaha stylee

new o2 sensors is a start

buffman

iTrader: (9)

very easy:

Black smoke = Rich
Blue smoke = Oil
White Smoke = coolant, or condensation burning off inside the exhaust (to an extent)

ToxicTA

Don't waste your time replacing the O2 sensors. If a O2 sensor goes bad you will know it. The will kick the check engine light.
If you are punishing it and you have soome light smoke I would consider that normal. Being that the lights were behind you it may have magnified the the smoke. If you would have ran him during the day you probably wouldn't have even noticed the smoke.

LS1Silverado05

iTrader: (41)

Yea, I can't see even a puff of smoke during the day. So it was either amplified by the headlights...or just an odd one time thing. Runs great.

MrCadillac

oh really? so O2 sensors can't wear out, and not throw codes? like in my caddy? pretty sure they were stock at 150k. O2 sensors can where out, cause a drop in fuel milage, and not throw a code? I thought they could.