bvanpouc

I am swapping a complete 2000 Blazer 4.3l engine & 4L60E into a '95 C1500 P/U. Got everything in and hooked up, but when I try to start it it fires and runs for a second than dies! It does this consistently, so I believe that the problem is due to the lack of a fuel enable signal being received by the PCM, but I cannot find a “fuel enable signal” wire on the PCM wiring schematic that I have! Does anybody know which pin on the PCM the fuel enable signal from the BCM (Passkey module) is supposed to go to?

ricksza

I assume you have the BCM and VCM from the 2000 Blazer.

The class 2 data line from the BCM to the VCM is circuit #710 yellow wire from BCM terminal A1 in connector C2 to VCM terminal 14 in connector C4.

bvanpouc

Unfortunately I don't have the BCM so I am trying to trick the PCM with a bypass module that supposedly generates the signal the PCM would normally get from the BCM.
So pin 14 on connector C4 (Black 24 pin) is the one looking for the fuel enable signal from the BCM! On my diagram it was just labeled as class 2 data, I thought that was just an output to the DLC.
Does the PCM need the signal continuously while running or just initially?
Thanks.

ricksza

It only looks for the signal on crank. Here's GM's description of the system:

Vehicle Theft Deterrent (VTD) Description
Passlock™ System
The theft deterrent system has been incorporated into the body control module (BCM). The theft deterrent is provided in order to prevent the vehicle operation if the correct key is not used in order to start the vehicle. The ignition key turns the lock cylinder. The cylinder rotation produces an analog voltage code in the passlock™ sensor. This voltage code is received by the BCM. The BCM compares the voltage code to the previousely learned voltage code. If the codes match, a class 2 message is sent from the BCM to the vehicle control module (VCM)/powertrain control module (PCM). The message enables the fuel injectors