Fuse blows when fuel pump runs
07-01-2019, 12:14 AM
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Car: 86 IROC w/Danko bodykit, 1988 iroc vert, 1989 k1500 pickup 6" lift and 35" tires, 2002 chevy tahoe z71
Engine: 383 stealth ram, 305 tpi, 350 tbi, 5.3l
Transmission: T56, 700r4, 700r4, 4l460
Fuse blows when fuel pump runs
Hey guys. Tried starting the car up after sitting for a few years. I have a 383 TPI set up with Holley Stealth Ram. Using 30 LB injectors being supplied by a 255 lph walbro in tank pump and an adjustable pressure regulator set for 45 psi. I also have the F.A.S.T XFI unit. When the key is turned, the pump fires up, gets to the 45 psi then trips the 7.5 amp breaker to the pump. Looking to see where you guys think i should start to look for where the problem might be
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69L48Z27 (07-01-2019)
07-01-2019, 11:31 AM
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Car: 86 IROC w/Danko bodykit, 1988 iroc vert, 1989 k1500 pickup 6" lift and 35" tires, 2002 chevy tahoe z71
Engine: 383 stealth ram, 305 tpi, 350 tbi, 5.3l
Transmission: T56, 700r4, 700r4, 4l460
Re: Fuse blows when fuel pump runs
That harness has been removed when the fast xfi was installed. From what I read it it says 20 amp fuse for fuel pump so not sure how the 7.5 got in there. Then again the car sat for a few years. Seems weird that when the pump gets to 45 psi which is what it's set for it pops the breaker unless it's the pressure causing it to pop
07-01-2019, 12:47 PM
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Re: Fuse blows when fuel pump runs
The higher the fuel pressure the more current the pump draws. A 7.5A fuse for a Walbro 255 is marginal at best. Should use at least a 15A fuse, along with larger wiring.
RBob.
RBob.
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69L48Z27 (07-01-2019)
07-02-2019, 07:49 AM
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Re: Fuse blows when fuel pump runs
I bought the "hot wire" mod/harness from Racetronix. Upgrades all the wiring, fuses, relays for the fuel system. I bypassed the factory relay all together. My Holley EFI pump trigger wire connects to the tan factory wire that was coming off the relay. Now instead of an undersized wire powering the pump, that wire now just activates the ractonix relay, power the pump. I can go into more detail if you're interested, but it's a good kit. Inexpensive, plug and play, and replaces all that old wiring.
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Rocket man (07-03-2019)
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