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Old 05-18-2013, 03:09 PM   #1
peglegs
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87 pump relay wiring

i have to run a 12v wire, what guage, from the block to the fuel pump relay to power my in tank pump, was tbi now carburated, which wire do i tap into to power the pump, i have the schematics but i cant determine which goes to the pump, tyvm
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1967 CST Long bed, big window, 350, Bowtie 2004r, 4:11 posi, p/s, pb

1987 chevy 4x4, long bed, 305/400
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Old 05-18-2013, 10:18 PM   #2
VetteVet
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Re: 87 pump relay wiring

If you look at the fuel pump relay in the top center of the picture and follow the gray wire down, it joins with a tan/white wire that goes to the hot fuel module and then to the fuel pump. The gray wire also goes to the oil pressure sensor. The power wire for the pump will carry the most current and should be the largest wire in the circuit. I would guess the gray and the tan/white wires would fit that description.

I have to ask you, do you have a carburetor that you are using now instead of the TBI and is the pump the same one that was used for that? If so then you must know that the fuel pressure will be too great for the carb and you'll need a pressure regulator to reduce it.
Are you planning on using the same harness and computer with the priming feature as the stock 87 used.





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Old 05-18-2013, 11:56 PM   #3
peglegs
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Re: 87 pump relay wiring

hey vette ty SO much for replying long story short i replaced the 305/tbi with a 96-2000 350 vortec crate LB. performance products intake, 600 edelbrock, pp regulator w/return line. no pressure at the reg. it would run for 3 mins or so then quit. the pump primed but no pressure. i finally ran a 18 ga. from the fuse block to the tan/wh wire from the ecm and dang it worked. lol.
the only computer related wires hooked up are the gas pump relay, gas pump prime and the oil sender so far so good, thanks again
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1987 chevy 4x4, long bed, 305/400
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