I'm gonna try to explain this problem as summarized as i can......

I have 87K miles on my 01 SS m6 and since i've owned it (20K miles) it has always used around a quart of oil between changes due to the typical ls1 pcv valve...

a little less than a year ago when i put my headers on i put new plugs/wires on and switched to castrol synthetic and in the last few months i've found myself having to add around a quart of oil every 1000 miles or so... a little more regularly than usual...

about two weeks or so ago i felt a small misfire in 6th gear under a strain upon which the check engine light would start blinking... i figured a coil was going bad because i have replaced a few in the past and the car acted the same exact way each time...at this time my friend noticed a puff of white smoke coming out of the car when i downshifted coming up to a red light... I scanned the car and found that the 5th cylinder was misfiring and both front 02 sensors were bad.. i bought 2 02's and a coil and put it on and it didn't fix the problem, meanwhile noticing a small amount of white/blue smoke at idle...

i then took the spark plug out and it was soaked with gas so i replaced it and didnt fix anything...i then replaced the wire and injector... still nothing except more blue/white smoke and a stronger misfire... I then feared for the worst but the engine makes absolutely no noise out of the ordinary and i have great oil pressure..... as of right now the smoke has gotten worse ... and upon any hard acceleration in any gear the car backfires terribly but doesn't really smoke unless i downshift hard or idle...

i'm doing a compression check tomorrow and i guess that will tell the tale... could it possibly be anything besides something internal?? it will prob end up being a leaking valve seal or hole in the piston but i can't imagine an 87k mile ls1 that was babied and had frequent oil changes..... i'm just hoping that it could possibly be something else causing it because tearing this motor down isn't something that i am looking forward to doing....

any help or advice would be greatly appreciated.

 

Post the compression test results then we'll know more

 

Stuck/cracked injector maybe?

 

as stated above, i replaced the injector... some are saying possibly leaking head gasket above that cylinder.....

 

I would like to hear some results as well. Sounds weird. I personally think you would be smoking pretty bad if it was a head gasket. Is the coolant level ok, or dropped at all?

 

You can also get the coolant sniffed for combustion by-products that will help to tell if a head gasket is gone. Also, were any of the plugs particularly clean? If so, that is another indication of burning coolant. One other idea, not sure if you have access to one, but a borescope into the cylinder might also provide some useful information.

 

If it's a head gasket, there would be constant white smoke, and it would run extremely rough. The blue smoke means that they're something with the piston, either it's cracked, or a ring cracked.
A compression check would rule out either of the two.

 

I'm willing to bet the piston ring took a dump. Best of luck with that...it definitely sucks.

 

did a compression test today...... 30 psi on the 5th cylinder.... OWNED

 

That stinks, I feel for ya! Do you think the nitrous contributed?

 

you may get lucky, and its only a cracked piston, and the block will still be ok

 

That sucks man. But now you have an excuse to make some real power.

 

bent valves or p-rods maybe. check it all as u r removing components.


fuerzaws6

 

i seriously doubt the nitrous was a factor.. i rarely ever made a full pass and bottle pressure was minimal. I was waiting to use it at the track when i got my new tires on... and as soon as i got tires, the cylinder went....it just sucks that i'm too broke for upgrades... i just need my everyday driver back for now.....

 

ok this is where i stand...

as stated above, i did a compression test and got only 30psi on the 5th cylinder.... now to figure out exactly what has happened....

There is no engine noise and i have great oil pressure. It simply feels just like i pulled off the plug wire to the 5th cylinder. Nothing more, nothing less.(besides the smoke at idle and some accelerations) I feel like if it was something major in the lower end there would be some kind of noise and the car would run like ***. The motor seems to be very smooth with just a small miss until put on a heavy load in a higher gear w/ low rpm.

i'm praying to find the problem when i pull the valve cover.

 

You could have bent a push rod, that's easy to tell. Pull the plugs if you can, or just put a wrench on the crank and watch the rockers. Watch the stroke. If it moves the entire cycle, then it's something with the piston.

Before you do any of this, you can squirt some oil in the spark plug hole, and do another test. If your PSI goes up, then it's a ring problem, or a piston problem.

 

Try having a Leak Down test done, that will tell you if it is the rings, or one of the valves (intake or exhaust).
A Leak Down test will tell you more than a Compression test and help isolate what and where the problem is without a complete take down. Atthat point at lease you will know what your into.

As far as the smoke.. could also be either be a bad Piston Oil Ring (wear or broken) or bad Valve Seal that causing it.