BCM and fuel pump relay question
12-04-2006, 11:42 PM
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BCM and fuel pump relay question I'm trying to figure out a no start problem on my 99 LS1 Formula. I realize it isn't a swap, but I thought someone here might know. Is the BCM fuel enable signal required before the PCM will turn on the fuel pump relay? My car cranks but won't start. No check engine light, no security light. I have power but no signal to the fuel pump relay. The signal wire, which is dark green/white, comes straight from the PCM. Swapping in a known good PCM didn't have any affect. So, what all is the PCM required to see in order to fire the fuel pump relay?
12-05-2006, 12:58 AM
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maybe your not grounded somewhere in the wiring. im unfamiliar with how its setup but if your getting power as you say and nothing happens then i would have to say the circuit isnt completed, meaning its not grounding.
12-05-2006, 07:04 AM
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Originally Posted by datboibrad
maybe your not grounded somewhere in the wiring. im unfamiliar with how its setup but if your getting power as you say and nothing happens then i would have to say the circuit isnt completed, meaning its not grounding.
12-05-2006, 05:55 PM
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If I remember right the VATS security is tied to the BCM. I can't remember if the VATS effects the fuel enable or not, but I'm pretty sure it's needed.
Kevin D.
Kevin D.
12-05-2006, 06:07 PM
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Originally Posted by Mojave
Is the BCM fuel enable signal required before the PCM will turn on the fuel pump relay?
yes
Originally Posted by Mojave
So, what all is the PCM required to see in order to fire the fuel pump relay?
12-05-2006, 06:39 PM
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Originally Posted by svt
yes
it must see a 30 or 50 hz square signal to start, my 2002 needs the 50 hz signal, not sure if the 99 is 50 or 30 hz. But this comes from the BCM I beleive or vats module if you are doing a swap, thats what I have.
it must see a 30 or 50 hz square signal to start, my 2002 needs the 50 hz signal, not sure if the 99 is 50 or 30 hz. But this comes from the BCM I beleive or vats module if you are doing a swap, thats what I have.
