LT1 - no a.c. voltage to ICM - other test results
05-23-2008, 06:51 PM
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LT1 - no a.c. voltage to ICM - other test results I am trying, for the first time since I purchased the combo, to start my 1994 LT1 w/4l60e that is now in my 1991 RX7 (This is my second LT1-RX7 conversion - The first went smoothly using LT1 Edit which I sold with the car). I have made a new wiring harness with all new OEM style terminals, appropriate color coded wire from www.EFI connection.com, & appropriate Metripak & Weatherpak connectors.
This harness connects via 9 metripak connectors to the original harness about 8" from the PCM plugs.
The engine cranks normally but does not start.
Am using the '94 PCM and have used Tuner to turn off VATS.
I am getting no spark @ plugs or coil wire. Additionally, my tach makes very small and quick movements that are barely perceptible but never registers anywhere near 100-200 RPM
So far:
getting pulses at a fuel injector when cranking based on flashes of a test light connected between the two injector terminals. Have 12V @ the injector.
getting 12V and 5V (2 terminals) and ground at Opti harness plug beside intake.
getting 12V at two terminals of ICM plug and ground at 1 terminal.
However, I am getting no indication of a/c voltage on the appropriate terminal of the ICM plug using my VOM and the A/C 200V scale.
getting 12V and ground for coil & low resitance on coil primary and 10k ohms on coil secondary.
Via backprobing the Opti harness connector beside the intake I also noted the two 5V wires showed reduced voltage upon cranking. One wire showed around 2.65V and was pretty steady while the other showed varying voltages of 0 or near 0 to the high 1V range.
I have not properly scanned the PCM for codes, having only the Tuner software and the USB - OBD1 cable from AKM.
Do I have enough evidence to condem the PCM?
Do I have enough evidence to assume the Opti optical circuits are working properly?
Any recommendations for PCM diagnosis/repair?
Thanks
This harness connects via 9 metripak connectors to the original harness about 8" from the PCM plugs.
The engine cranks normally but does not start.
Am using the '94 PCM and have used Tuner to turn off VATS.
I am getting no spark @ plugs or coil wire. Additionally, my tach makes very small and quick movements that are barely perceptible but never registers anywhere near 100-200 RPM
So far:
getting pulses at a fuel injector when cranking based on flashes of a test light connected between the two injector terminals. Have 12V @ the injector.
getting 12V and 5V (2 terminals) and ground at Opti harness plug beside intake.
getting 12V at two terminals of ICM plug and ground at 1 terminal.
However, I am getting no indication of a/c voltage on the appropriate terminal of the ICM plug using my VOM and the A/C 200V scale.
getting 12V and ground for coil & low resitance on coil primary and 10k ohms on coil secondary.
Via backprobing the Opti harness connector beside the intake I also noted the two 5V wires showed reduced voltage upon cranking. One wire showed around 2.65V and was pretty steady while the other showed varying voltages of 0 or near 0 to the high 1V range.
I have not properly scanned the PCM for codes, having only the Tuner software and the USB - OBD1 cable from AKM.
Do I have enough evidence to condem the PCM?
Do I have enough evidence to assume the Opti optical circuits are working properly?
Any recommendations for PCM diagnosis/repair?
Thanks
05-26-2008, 04:05 PM
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Have a chuckle on me!
I reversed the two white wires that connect to plug B on the PCM.
So, I was sending the ICM triggering signal to the 3-2 shift solenoid.
It runs like a champ now.
I reversed the two white wires that connect to plug B on the PCM.
So, I was sending the ICM triggering signal to the 3-2 shift solenoid.
It runs like a champ now.
