Need and ECU expert :(
02-12-2008, 10:37 AM
#1
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Need and ECU expert :( 
I've got a 99 LS1 in an RX7 and it's been driving fine for the first 90 miles. Yesterday I went to calibrate the Autometer speedo and the car died on me while driving. So far this is what happened. After completing the 2 mile calibration drive, I noticed the speedo didn't read any mph at all now. Just stayed at 0. Ok, I was dissapointed and started to drive home. While driving, the car chugs, and dies so I pull over. Figured fuel because of the sputter and fuel rail didn't have any pressure. I hitch a ride home and come back with some wire to hot wire the fuel pump at least to get it home. Hot wire the pump, it comes on and I get pressure. Car still won't start. I noticed the voltmeter is moving between 8-10 volts. OK, so now I figured I blew an alternator and didn't notice, battery is weak. I get a buddy to come tow me home, and on the way, the dash starts to smoke, quits smoking, and voltmeter goes back to 12. OK so I had a short in the dash that burned through but car still won't start. Here's where my question finally starts. I've got a wire running from the speedo to the vss output coming off the ecu. There is also a constant hot wire I ran up in there for gauges, radio, things like that when I kill power to the chassis. I havn't had a chance to tear in and inspect it, but I have a feeling since the speedo wasn't registering speed, is that the constant hot might have somehow rubbed through insulation of it and speedo signal wire cuasing a short and speedo not to work. If that happened, would 12 volts running down the vss back to the ECU fry it? The car won't start even with enough juice. I know it's long, just wanted to give the full details. Anyone???
02-12-2008, 10:56 AM
#2
Did you put a gauge on it to verify just how much pressure it has. It can flow what seems to be enough fuel yet still not be enough pressure or volume to allow the engine to run.50-62PSI KOEO is the target area. Chances are it did not cook the pcm I've had a couple of harness rub through under the hood and short 12v to various pcm components and they survived.