LS1 engine problem
Thread Starter
Burning Brakes
Joined: May 2003
Posts: 850
Likes: 0
From: Green Lane Pennsylvania
LS1 engine problem
This isn't Corvette related except for my signature, but my son has a Trans Am with a cammed LS1 in it. It isn't running right one plug is not firing. He took it to a engine shop that can't figure it out because it is not throwing any codes. They did a leak down test which checks out fine.
I am thinking it has to be a coil or a clogged fuel injector. Any advice on what the problem could be or why it isn't throwing codes?
I am thinking it has to be a coil or a clogged fuel injector. Any advice on what the problem could be or why it isn't throwing codes?
Guest
Posts: n/a
If you have a good scanner it should show which cylinder it's misfiring on. You can also just unplug the injector and coil for each cylinder and whichever cylinder it doesn't change the idle on is the problem cylinder. Then make sure that cylinder is getting air, fuel and spark.
Melting Slicks
Joined: Sep 2005
Posts: 3,082
Likes: 0
From: eagle mountain utah
misfire
If it is misfiring because of no spark, then the charge that goes past the front O2 will be rich and will cause the short term fuel trims to go negative or pull fuel out. The front 02 reading might go higher than normal, like .8 or .9. If it misfires because of not enough fuel getting throuhg the injector, it will cause the short terms to add fuel or go positive. The O2 sensor reading will go lean and show a low voltage reading, like .1 or .2. If it misfires because the injector sticks open, then it will look like it is misfiring because of no spark.
Instructor
Joined: Jul 2004
Posts: 110
Likes: 0
From: Newport News VA
If you know which cylinder the misfire is in, try swapping the coil with one on the other side. If the mis follows the coil, then you've found the culprit. If the mis stays with the cylinder, try swapping injectors with one from the other side. If it follows, then its a bad injector. If the mis stays with the same cylinder after both, check the wiring to the coil and injector.
Has your son desensitized the misfire tables? A good size cam will set the misfire codes if the lope is big enough.
Has your son desensitized the misfire tables? A good size cam will set the misfire codes if the lope is big enough.
