Why won't my fuel pump turn on?

Tiny
BRENTTEETS
  • MEMBER
  • 1987 PONTIAC FIREBIRD
I worked on a 1987 Firebird 5.7L about 2 weeks ago. The guy said it needed a new brain. So I replaced the ECM and prom. Took the car out for a ride but was having a issue with it stalling and fuel pump was shorting out. Jumped the car and while jumping fuel pump worked 100%. Realized the connection to the battery was real loose and once tightend the fuel pump worked great. The battery was pretty much dead so he took it to get charged. When he put it back in the fuel pump won't work at all. I put a test light on the fuel pump relay and i'm not getting any of the wires to light up ( I also did it with the MAF sensor relay and the MAS sensor relay. And no wires lit up). I unhooked the wire harness from the ECM and tried to use the test light on the fuel pump relay spot of the wire harness and again no light.
Monday, September 26th, 2011 AT 1:13 AM

3 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
First, get back to basics and forget about the ecm.
You cleaned the battery and got it to go. My guess is that the customer may have hooked up the battery wrong and either blew fuses or fusible links. Look at the power supplies first before replacing parts that dont need to be replaced.

Roy
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Monday, September 26th, 2011 AT 1:20 AM
Tiny
BRENTTEETS
  • MEMBER
  • 4 POSTS
I checked all the fuses in the fuse box. I was told that there are fusible links on the starter that could have went bad from arcing or something. That seem right to you?
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Monday, September 26th, 2011 AT 1:22 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Yep. Just as I told you. Look at the starter and you will see about 3 wires coming off the fat terminal. One or more may be broken or burned through. If they are, you need to replace them with the exact replacement to protest the harness.
Then, you need to find out why they burnt or you have not found the problem.

Roy
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Monday, September 26th, 2011 AT 1:41 AM

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