Odd pcm behavior in conversion
10-19-2007, 09:35 PM
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Odd pcm behavior in conversion I have have had an LS2 running with an LS1 harness and computer for over a year now. I have not had any problems until tonight.
I was alone on the road and rolled into the throttle pretty hard, and almost immediately the car acted like it was losing pcm connection. Gauges go nuts, engine revs down then back up, dash lights come and go. I have had this problem before and it was a pcm ground. I pull into a parking lot to check things out. At first I try to restart and get nothing but a single click when I hit the starter, as if the computer was giving me 12V at the starter. That happened a few times, so I pulled the pcm fuse for 20 seconds. Put the fuse back in and the car would start up and die quickly thereafter. After doing that twice, I took out a 1ft long socket extension and grounded the computer housing to the hood hinge. The car started up fine and idled like normal. I expected it to die when this rigged ground was removed, but it didn't. I drove 8 miles home under light throttle (and under 2500 rpm) with no problem. Once on my street, I accelerated in 1st gear up to 4000 rpm throttle and got the security light to come on, and then go off. Now that I think about it, I can't be sure but I think that I turned the VATS off with HP Tuners. I wil check that.
My last trip in the car before tonight was a 90-mile round trip to an 1/8th-mile track where I made 3 passes without this problem.
Any ideas out there?
Thanks.
I was alone on the road and rolled into the throttle pretty hard, and almost immediately the car acted like it was losing pcm connection. Gauges go nuts, engine revs down then back up, dash lights come and go. I have had this problem before and it was a pcm ground. I pull into a parking lot to check things out. At first I try to restart and get nothing but a single click when I hit the starter, as if the computer was giving me 12V at the starter. That happened a few times, so I pulled the pcm fuse for 20 seconds. Put the fuse back in and the car would start up and die quickly thereafter. After doing that twice, I took out a 1ft long socket extension and grounded the computer housing to the hood hinge. The car started up fine and idled like normal. I expected it to die when this rigged ground was removed, but it didn't. I drove 8 miles home under light throttle (and under 2500 rpm) with no problem. Once on my street, I accelerated in 1st gear up to 4000 rpm throttle and got the security light to come on, and then go off. Now that I think about it, I can't be sure but I think that I turned the VATS off with HP Tuners. I wil check that.
My last trip in the car before tonight was a 90-mile round trip to an 1/8th-mile track where I made 3 passes without this problem.
Any ideas out there?
Thanks.
