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90 ss454 swapped to carb help

Old 07-13-2017, 12:51 PM
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Default 90 ss454 swapped to carb help

I posted once but it is MIA I don't see it,,so here goes again..

History 90 ss454 c1500,,has been upgraded to 496,,I have swapped the TBI to a carb,,I swapped the factory style distributor out for a single wire HEI style.I added a holley electric fuel pump to frame rail.I used the original pump hot wire (the grey one) and ran a new ground.I pulled original pump out and removed the pump and added a steel tube to the stock length of old pump depth..
Now then the pump runs fine off the grey wire for about 20 sec then it shuts off..

My question is,since I replaced the stock style distributor I assume there is no signal from it too ECU to tell the pump to stay on...So do I need to run an entirely new wiring to my new pump or does anyone know of a work around to keep the replay as stock...?

Tks in advance for any replies
Old 07-14-2017, 08:33 AM
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Simple fix!! The gray wire is still seeing signal through the trucks stock fuel pump relay that is mounted right beside the hood hinge on driver side fender. You need to mount a new relay and wire it up and let the gray wire be the power to pump and the give the relay a switched 12v, a ground and a constant 12v as normal. Problem solved. I went through this many years ago when i first swapped mine over to carb aswell :-)
Old 07-18-2017, 12:41 PM
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Tks BigBlock90,,,hey can't I just change the fuel pump drive from the ECU ? I think it's the green/white wire to a switched 12v ign on source> Like the coil hot wire? then I can leave the relay as is...Just asking..lol

Also on my stock relay I don't have a grey wire but going to the pump I do..Maybe it changes color somewhere else? I do have a tan/white wire which I see in a diagram could also be grey..
Old 07-20-2017, 10:36 AM
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???? Bump
Old 07-21-2017, 08:48 AM
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Yes you can clip the switched power wire from the factory harness that feeds the relay from the ECM and just put a switched 12v wire to it and use the same relay. I chose to run a new relay all together and not cut the factory harness in mine.
Old 07-21-2017, 09:46 AM
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tks,I have everything gathered that I will need,a 40amp relay and plenty of wire...I think I'm gonna try the switched wire on the stock relay first,,and see how that goes..If need be as I said I have what I need to run my own circuit...Tks again

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