2003 Express Van LQ4/4L80E harness & PCM - no tach output signal
03-31-2013, 01:41 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
2003 Express Van LQ4/4L80E harness & PCM - no tach output signal
After finishing prepping the harness for the swap, I realized I didn't mark any connector or wire for tach output. I have pinouts for early Camaro & Vette LS1's (up through 2002), and see the tach output signal is red connector pin 10 on all of them. This PCM has blue and green PCM connectors, so I assumed green corresponded to the red Camaro & Vette connector. In Pocket's famous LS wiring thread, he posted a 2002 Express van pinout that indicated green connector pin 10 is for the tach. Another internet resource indicated the same. Looking at the Mitchell diagram I found online (attached), green connector pin 10 is unmarked. Looking at the harness, green connector pin 10 is blanked out.
I assume I can add a pin to that location, but I'm wondering if the PCM needs to have something done to the programming for the output to work. (The PCM is at the tuners now for a bench tune in hopes that I can at least fire the engine with this newfangled configuration.)
I assume I can add a pin to that location, but I'm wondering if the PCM needs to have something done to the programming for the output to work. (The PCM is at the tuners now for a bench tune in hopes that I can at least fire the engine with this newfangled configuration.)
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