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Fuel Pump Won't Prime

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Old 07-21-2012, 08:28 PM
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Fuel Pump Won't Prime

Hello Everyone, I need a second opinion on this. I changed the fuel filter yesterday and my car will not start up and the fuel pump will not prime. I followed the directions on my Chiltons Manuel,

1. pulled the 2 fuses in the fuse box (fp/inj2 and inj1) until the engine runs out.
2. I uninstall the old fuel filter, let the gas drain, then reinstall the filter.
3. put the fuses back and put a gallon of gas back into the tank. Now my car does not start.
4. all my accessories are working fine except I don't hear my fuel pump priming. the fuel pump was working fine and priming before i changed the fuel filter.

Can someone please help me with this problem? does anyone else have run into this issue?
my car:
87 IROC-Z 5.7 TPI

Thanks,
Old 07-22-2012, 11:35 AM
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Re: Fuel Pump Won't Prime

Originally Posted by Keith Yee
Hello Everyone, I need a second opinion on this. I changed the fuel filter yesterday and my car will not start up and the fuel pump will not prime. I followed the directions on my Chiltons Manuel,

1. pulled the 2 fuses in the fuse box (fp/inj2 and inj1) until the engine runs out.
2. I uninstall the old fuel filter, let the gas drain, then reinstall the filter.
3. put the fuses back and put a gallon of gas back into the tank. Now my car does not start.
4. all my accessories are working fine except I don't hear my fuel pump priming. the fuel pump was working fine and priming before i changed the fuel filter.

Can someone please help me with this problem? does anyone else have run into this issue?
my car:
87 IROC-Z 5.7 TPI

Thanks,
Find the power leads under the car that go to the fuel pump. ON the drivers side at the rear of the car, tucked up under the quarter panel by the muffler exit, should be a wire harness. Tha'ts the harness that goes to the fuel pump/sending unit.

Disconnect it, and jumper 12v to it and see if the pump comes on that way. If it does, then it's a relay/wiring issue. If it doesn't, your pump died.
Old 07-28-2012, 06:23 PM
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Re: Fuel Pump Won't Prime

Well I unhooked the wiring harness today and I tried to jump it to a battery and I got nothing. I connected a wire to the black wire on the wire harness and gray wire to positive on the battery and nothing. I think the fuel pump is dead.

i noticed when I unhooked the harness, the fuel gauge went all the way to full and when I connected back together, it went back to normal.
Old 07-28-2012, 06:27 PM
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Re: Fuel Pump Won't Prime

the gauge uses the resitance in the tank from the float to give a reading which is why it pegged when you disconnected it.

From what you said, sounds like the pump died.
Old 07-29-2012, 12:59 AM
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Re: Fuel Pump Won't Prime

Well the next step for me is to replace the fuel pump. Its gonna be a Pain in the ***. I think my iroc is done for the summer. Now I have to decide if I should drop the tank or go with the trap door method.
Old 07-29-2012, 03:38 AM
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Re: Fuel Pump Won't Prime

Originally Posted by Keith Yee
Well the next step for me is to replace the fuel pump. Its gonna be a Pain in the ***. I think my iroc is done for the summer. Now I have to decide if I should drop the tank or go with the trap door method.
Well, I'm never one to advocate cutting up a car. With my power tools (I have an air tank and pneumatic tools), it took about 8 hours to drop the tank, install my new pump and then put the tank back up. I didn't know what I was doing so I was going a bit slow. do your research, you'll need 4 jack stands. Two to hold the car and two to hold the dif (I used the jack to lower the dif to the right height). The worst part was the exhaust, I had to remove it from the cat because there was no disconnect near the tank.
Old 07-29-2012, 09:36 AM
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Re: Fuel Pump Won't Prime

Cutting the car and the sending unit pipes sounds good in the near term, but usually backfires in the future with rust, water intrusion and possible fuel system problems.

My exhaust was a little worse than OZZ1967. The shop that put in the muffler and cat back pipe welded EVERYTHING. Had to disconnect at the headers to get it low enough to get the tank out.

One hint. When you think you have the clearance to pull the tank and it still refuses to come out, look up in the fuel filler neck area. There is a lip at the top of the filler neck that likes to get caught. Just stick your hand up there and guide it through the opening. I spent 15 minutes fighting it the last time I pulled the tank (4th time for a 3rd Gen tank pull).

Good luck.
Old 07-30-2012, 11:54 PM
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Re: Fuel Pump Won't Prime

Man I am in a dilemma, should I use the trap door method to replace the fuel pump or should I drop the rearend,exhaust, and everything else to drop the tank. I've been reading a lot of posts about this and some people say its good and some people say its not. I really love my car. Second owner of a 87 IROC 5.7 TPI. Its probably the original fuel pump that is 25 years old and it finally died after a stupid fuel pump change. Maybe I should exhaust all options, to make sure the fuel pump is 100% dead
Old 07-30-2012, 11:59 PM
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Re: Fuel Pump Won't Prime

If you're in that much of a dilemma dude, drop the tank. You cut and if youre not happy, you may regret it and now you've got a hole in your car forever.
Old 08-02-2012, 03:03 PM
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Re: Fuel Pump Won't Prime

Dropping the tank is EASY! You just jack it up in the air and wiggle it out! 2 hours tops! You don't even have to unbolt the suspension. 2 friends and a 6 pack will make it go by fast. Good luck!
Old 08-02-2012, 04:00 PM
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Re: Fuel Pump Won't Prime

You do need to detach the rear shocks from the axle brackets and let the axle down as far as you can for clearance. Then you have to remove the exhaust as Ozz1967 stated. The exhaust is usually the hardest part. Zig pointed out the one other little issue of wiggling the filler neck through the opening in the fuel door trim. I have done several 3rd gen tank drops and would never consider for a moment cutting up a car to make an access panel.
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