New PCM, fuel pump does not turn on--sure way to check if PCM is functioning?
09-08-2007, 05:35 PM
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New PCM, fuel pump does not turn on--sure way to check if PCM is functioning? So my car has slooooooooowly been going back to stock. I ordered a new PCM for the car loaded with the correct software for my car (VIN)
My fuel pump does not turn on, however it seems that power is going back there. I am thinking that the PCM is not telling the fuel pump to turn on. By the way it is the racetronix setup.
So is there a sure way to tell if the PCM is working? Or any trouble shooting I can do?
Also the person I bought the PCM from gave me some instructions about turning the car to on, waiting for the security to go off, and repeating three times. The security light goes off after 5-10seconds where the instructions said it would take ten minutes for the light to turn off. HELP!
My fuel pump does not turn on, however it seems that power is going back there. I am thinking that the PCM is not telling the fuel pump to turn on. By the way it is the racetronix setup.
So is there a sure way to tell if the PCM is working? Or any trouble shooting I can do?
Also the person I bought the PCM from gave me some instructions about turning the car to on, waiting for the security to go off, and repeating three times. The security light goes off after 5-10seconds where the instructions said it would take ten minutes for the light to turn off. HELP!
09-09-2007, 12:10 PM
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Is this for your Trans Am? If so, the security relink procedure you are referring to (key on/off 3 times for 10 minutes) is not required. The F body cars use a PWM signal from the BCM to activate fuel. The security relink procedure is required for vehicles utilizing a password exchange via the Class2 bus (Corvette, 00+ trucks, etc).
If VATS is not disabled in the PCM (it wouldn't be disable if the program loaded in the PCM is stock), the PCM will be expecting that PWM signal from the BCM to enable fuel. If the signal is not provided, the fuel pump will not prime.
I have also seen a non-fuel prime condition when the ROM is corrupted in the PCM, but that was on a 1998 F-body car which uses a different PCM. Still, I would expect the later PCM to do the same thing under this condition.
If VATS is not disabled in the PCM (it wouldn't be disable if the program loaded in the PCM is stock), the PCM will be expecting that PWM signal from the BCM to enable fuel. If the signal is not provided, the fuel pump will not prime.
I have also seen a non-fuel prime condition when the ROM is corrupted in the PCM, but that was on a 1998 F-body car which uses a different PCM. Still, I would expect the later PCM to do the same thing under this condition.
09-09-2007, 12:54 PM
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There is a "relink VATS" function on my HPTuners, the procedure
ends with a multiple key-on sequence. You might just want to go
through the drill, for yucks. However when I went to a spare PCM
many years ago no such thing was necessary. I did though have
the realership reflash it to my VIN so maybe that was all just
taken care of.
If you see power back at the pump harness, check that the other
side of the pump motor is getting ground.
ends with a multiple key-on sequence. You might just want to go
through the drill, for yucks. However when I went to a spare PCM
many years ago no such thing was necessary. I did though have
the realership reflash it to my VIN so maybe that was all just
taken care of.
If you see power back at the pump harness, check that the other
side of the pump motor is getting ground.
