Major problem with LS1 help needed please
03-19-2007, 11:35 PM
#1
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Major problem with LS1 help needed please
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.
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.
Last edited by ponykiller z28; 03-19-2007 at 11:49 PM.
03-20-2007, 01:16 AM
#3
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i definitely believe that the faulty pcv valve has been causing me to lose a quart between changes but the fact that the major misfire that i have is all coming from the 5th cylinder even after changing coil, wire, plug, injector is what scares me.... the smoke came as the miss got worse
03-20-2007, 06:57 AM
#4
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Location: Oshawa - Home of the 5th-gen
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Possibly a bad head gasket? (white smoke, a.k.a. "steam", can be from water going through a cylinder) or maybe just an intake gasket 
.
Also, if that cylinder were losing compression (again, going on the theory of a bad head gasket) then it's also not going to burn as efficiently, thus, more smoke.
Dunno, may be way off, but it's a thought ..... hopefully the expensive parts are still good, and at worst you need new gaskets
.
.Also, if that cylinder were losing compression (again, going on the theory of a bad head gasket) then it's also not going to burn as efficiently, thus, more smoke.
Dunno, may be way off, but it's a thought ..... hopefully the expensive parts are still good, and at worst you need new gaskets
.
03-20-2007, 10:22 AM
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03-20-2007, 04:14 PM
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03-21-2007, 12:18 AM
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03-21-2007, 08:56 AM
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03-22-2007, 12:01 AM
#14
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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.
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.
03-22-2007, 02:26 AM
#15
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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.
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.