JEB99TA

iTrader: (32)

My car's got 36,800 hard-driven miles on it. It starts smoking (black smoke) at about 4,500 rpm's and gets worse the higher the rpm's go > until it reaches about 5,600 rpm's and then the smoke turns white until it changes to a higher gear and then it's OK until it hits high rpm's again ... at which time it starts smoking black smoke again.

Could it be a bad PCV valve or is it what I think it is ... bad rings???? I don't believe the rings would be bad with only 36,800 miles on it. I have to add a quart of oil every 300 miles. Has anyone had this happen with such low mileage?

Lvmyz28

iTrader: (1)

I think it's a little more serious than a PCV valve. It sounds like you have a leak in one of your cylinders whether it be a blown head gasket or a bad valve or both. You need to do a leak down test and pressure test to find out if the cylinders are pumping up. If they aren't then the heads must come off and find out what's wrong!

JEB99TA

iTrader: (32)

Oh MAN!!! I sure don't need serious engine problems right now ... always stuff happens at the very worst of times. Would you take it to the dealership for testing or would you have it done at a Performance Shop? Maybe this would be a good time to change heads???

ROGERSPERF.

Black smoke is usaly a sign of over rich condtion i would have some one look at the fuel tables in the computer.

JEB99TA

iTrader: (32)

There's one more thing I should have mentioned: behind the front passneger-side tire, there's a dark film of black oily substance on the underside of the fendrewell and the right side of the car. Yet, there's no obvious signs of oil leaking ... had it up on ramps and checked it thoroughly. There are no oil leaks at all.

ROGERSPERF.

With out seeing that i don,t know what that could be from.If it was a head gasket water temp would go up and you would see bubbles in the rad.It also may mix with the oil so check your oil to see if the level has gone up and it looks like a milk shake.It would also have a miss.

JEB99TA

iTrader: (32)

Runs stronger than ever ... oil is blacker than it should be after I changed oil only about 1,200 miles ago. Runs cool in hot temps today. It has great oil pressure and idles really smooth. The oil on the side looks like it's some sort of 'blow-back' rsidue or something ... weird. Since the PCV valve has never been replaced, for $3.00 bones, I'll go ahead and replace the PCV valve ... try to eliminate the cheaper stuff first. I appreciate your help on this, BTW.

ROGERSPERF.

Ok giving me more info oil is blacker that could be do to the over rich condion witch would lead to what you said about white smoke.You could be gas washing the cylinders from rich condtion.Is the check engine light on?

I would take it to the dealer before you do any head swap.You need to get this problem straighten out first.

JEB99TA

iTrader: (32)

No SES light. But, what you are saying is making sense. This wasn't happening until I changed a bunch of stuff. 3 months ago, I ditched the shorties, catted Y, LS1 intake, and stock TB. I replaced all this stuff all at once with a ported Jantzer TB, LS6 intake, MAC 3/4 length ported headers and MAC ORY.

It seems like this was when it started ... the massive oil loss and the black smoke. When I had it dyno-tuned (just after all the changes), on decleration, it backfired several times (while on the dyno) and shot 6 - 8" orange flames out the Borla tips ... a lot of black smoke, as well, just before deceleration ... then white smoke followed.

I chalked it up the raz or fuel light-off. I believe it's very possible it may be fuel related, but, not sure why that would make it consume or blow out that much oil ... about a quart every 300 miles.

JEB99TA

iTrader: (32)

Almost forgot. I chnaged all the plugs out and the old ones all are dry and sort'a light-brown ... no oiling/fouling. They all looked identical. If the rings were bad in one of the cylinders, would the plug have some oil on it? Just trying to rule rings out. Like I mentioned earlier, the car only has 36,800 miles on it.

ROGERSPERF.

The reason it backed fired was because of raw fuel in the ex. system.If you watch nascar races at night when they back off it slams the butterflies closed and lights of the fuel in the ex. system.when you were on the dyno did you get an A/F RATIO print out if so look at it and see if it is some wears down around 10:1 or even 9:1. it should be up around 12:1 or even 13:1.The reason for oil loss is fuel wash from running rich and you have glazed the cylinder walls to the point the ring don,t seal any more The rings in a LS1 are only 1.5mm 1.5mm by 3mm.

ROGERSPERF.

From what you are telling me it sounds like the oil ring is ok but the top and second ring are glazed over a bit and leaving enought oil to get in the combustion chamber but not enought to show up on plugs.The second ring has two functions to help the top with comp. and help the oil ring control oil.

JEB99TA

iTrader: (32)

The A/F on the dyno sheet is nearly dead-on the 13:1 line all the way accross the rpm range between 4,800-6600 rpm, however, it's at 14.2:1 between 4000-4800 rpm. Can anything be done to corect the glazing, short of tearing down the engine and replacing the rings?

ROGERSPERF.

If not to bad they will seat back in.Iwould find the cause of the rich condtion first.

jimmyblue

iTrader: (11)

Black is fuel, gray is oil, white is antifreeze is the
old wisdom.

Black is soot, hydrocarbons, likely cause is misfires.
A modest over-rich condition just makes CO while
lean makes HC early on. Super-rich also elevates
HC but I don't get that impression here. You might
look for any signs that you have a single injector that
maybe doesn't pull its weight at the higher end. An
imbalanced set can give you an average AFT that's
right, but nobody's entirely happy. What's the ping
situation when this smoke show is going on?

It's odd that you are that lean down low (14.2) and rich
up top. Do you have numbers from your PE table and
your open loop fuel/air table? 14.2 is almost unenriched.
I wonder whether there's some weirdness about PE enable.

JEB99TA

iTrader: (32)

The problem was A/F related > too rich because the PCV valve was apparently sticking, probably staring it for air. It didn't rattle when I took it off. It clunked. I went down the road a few minutes ago and bought a Purolator PCV valve for $2.44.

When I drove down the highway, I dawg'd it hard several times and not one trace of smoke ... black, gray, blue, or white!!!! Thanks for all your help guys.

Since it was all clogged up and smoking when I dyno'd, I'm curious if you think my dyno numbers might improve a little bit? I know that it feels stronger than ever before. I think I'll ask NLP to do a couple more dyno pulls for me.

ROGERSPERF.

Re read the post the oil you see under the car could it be the intake manifold leaking in the back on the passangers side the gray would be oil and it may pull in some water witch would be white.The black is rich.

JEB99TA

iTrader: (32)

ROGERSPERF. > you must have hit ENTER before I did ... LOL!!!! I think there may be some sort of crankcase 'blow-back' valve on these cars or something that was causing the mist of oily smoke when the valve was clogged, maybe due to crankcase pressure. Of course, this is all speculation on my part because I don't really know as much as I should about the basic technical aspects of the emissions side of the vehicle. There's no oil underneath the airlid, filter, or in the throttle body. The intake doesn't have a lot of excess oil.

I wound that thing tighter than a banjo srting and not a lick of smoke ... talkin' about one happy LS1 driver here ... hehehe!!!! It's nice that you folks would take the time to follow this thread through to try and help. You've definitely improved my knowledgeBase and given me a drive to learn more about our LS1 engines.

ROGERSPERF.

Good luck with your car and thank you for your service to keep us safe.

JEB99TA

iTrader: (32)

Thanks ... 30,000 service was done at my dealership ... guess they missed the PCV valve ... even paid to have them do the additional 'dealership recommended but not required service' ...