HELP in the Tampa Bay area.
05-12-2012, 06:24 PM
#1
Staging Lane
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HELP in the Tampa Bay area. Guys,
I need some help. I have a engine misfire and can't figure it out. Could be a burnt valve.
The car is still drives o.k. so I can drive it.
Anyone have good troubleshooting skills that could just help me determine the cause?
Thanks
I need some help. I have a engine misfire and can't figure it out. Could be a burnt valve.
The car is still drives o.k. so I can drive it.
Anyone have good troubleshooting skills that could just help me determine the cause?
Thanks
05-12-2012, 07:31 PM
#3
Staging Lane
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Mods: Engine is a 1998 LS1. Intake system is a 4" with conical filter. LS2 MAF. I have altered the programming but flashed the stock program back on when I noticed that the problem became worse.
Dual exhaust with x pipe. I am ready to mod it more but need to find this problem out first.
Replaced plugs, plug wires. Checked spark on each cylinder with light. Checked fuel injector spray pattern with injectors removed from manifold. Checked for vacuum leaks at manifold and vacuum lines. I removed valve covers and ran engine and checked for broken valve springs. Ran codes but didn't find anything although LTFTs are about -12. O2 sensors seem a bit sluggish at idle but seem fine and spark plugs are clean and dry. Engine does not use any oil so I think the rings are fine.
I ran a compression check but will repeat it as I forgot to disconnect the fuel pump. The engine did have 3 bent pushrods, which leads me to a possible bent or burnt valve.
I probably need to perform a leak down check but do not own that tool. I am also stuck with just basic tools as I have not moved most of my tools here yet which is also making this difficult.
The misfire is very evident listening to the exhaust system but since I have an x pipe you can't tell which side it is coming from. Hopefully I didn't forget anything that I have already checked.
Dual exhaust with x pipe. I am ready to mod it more but need to find this problem out first.
Replaced plugs, plug wires. Checked spark on each cylinder with light. Checked fuel injector spray pattern with injectors removed from manifold. Checked for vacuum leaks at manifold and vacuum lines. I removed valve covers and ran engine and checked for broken valve springs. Ran codes but didn't find anything although LTFTs are about -12. O2 sensors seem a bit sluggish at idle but seem fine and spark plugs are clean and dry. Engine does not use any oil so I think the rings are fine.
I ran a compression check but will repeat it as I forgot to disconnect the fuel pump. The engine did have 3 bent pushrods, which leads me to a possible bent or burnt valve.
I probably need to perform a leak down check but do not own that tool. I am also stuck with just basic tools as I have not moved most of my tools here yet which is also making this difficult.
The misfire is very evident listening to the exhaust system but since I have an x pipe you can't tell which side it is coming from. Hopefully I didn't forget anything that I have already checked.
Last edited by C5AJ; 05-12-2012 at 07:39 PM.
05-13-2012, 02:04 AM
#5
On The Tree
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Well if you replaced the pushrods and it still does it, you're on the right track. Sounds lime you have a pretty good hang on it, just need to go till you find the problem.
05-13-2012, 10:05 AM
#6
Staging Lane
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After the compression check, and possibly a leak down, the diagnostic is finished and I will have to tear into the engine to continue to find the problem, and hope that I can. I was hoping maybe an LS expert (one that has dealt with these engines a lot)on here would be able to help.
