Lt1 misfire (resolved)
Lt1 misfire (resolved) Well, as many asking help and never posting the solution for the problem, I figure I should post the resolution to my problem for a change. Last year the car started misfiring after it was running for a little bit. No check engine light and no scan tool so I was on my own.
Tested some stuff, found the fuel pressure was dropping when raising the rpm, so I decided the fuel pump was bad and replaced it recently with the Racetronix unit, with no differences in running(although it starts quicker). Fuel pressure is still low, but after reading some posts, the fuel pressure seemed like it might not be my problem after all.(Those of you curious, the pressure at idle was about 41, and would drop down to about 35 when free revving to 3000 rpm approximately. BTW Is this normal operation? I'm going to add the hotwire kit for the fuel pump when I have time.)
Finally the check engine light would come on, so I finally decided to get a cable for the laptop, and checked the code, found driver's o2 sensor lean code. Looked at the measured values and found(key on engine off) that the right sensor was at about .45 volts, and that the left sensor dropped down to .004 volts. Checked it while running and it barely moved. Replaced with a denso o2 sensor, and it's running as good as it ever has.
Tested some stuff, found the fuel pressure was dropping when raising the rpm, so I decided the fuel pump was bad and replaced it recently with the Racetronix unit, with no differences in running(although it starts quicker). Fuel pressure is still low, but after reading some posts, the fuel pressure seemed like it might not be my problem after all.(Those of you curious, the pressure at idle was about 41, and would drop down to about 35 when free revving to 3000 rpm approximately. BTW Is this normal operation? I'm going to add the hotwire kit for the fuel pump when I have time.)
Finally the check engine light would come on, so I finally decided to get a cable for the laptop, and checked the code, found driver's o2 sensor lean code. Looked at the measured values and found(key on engine off) that the right sensor was at about .45 volts, and that the left sensor dropped down to .004 volts. Checked it while running and it barely moved. Replaced with a denso o2 sensor, and it's running as good as it ever has.
Last edited by Zebisko; May 13, 2012 at 11:55 AM. Reason: additional info
