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Old 02-12-2026, 10:19 AM   #7
Custom 68
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Join Date: Nov 2001
Location: Springfield, MO
Posts: 2,970
Re: Gen 5 fuel pump questions

Quote:
Originally Posted by Joyridin View Post
When the harness was reworked, there is a relay specifically for the electric fuel pump. I just ran it from there.

Realistically, all you have to do is pull a small keyed voltage off the switch, computer, or fuse box to a relay. Let the relay carry the load.

I mounted all the hoses etc at the back of the vehicle (tank in rear) and only have a feed line going up front. It was easy and after 4 years and thousands of miles, no problems at all.
Quote:
Originally Posted by LS short box View Post
On my LS swaps the fuel pump was controlled by the ECM. When you turn the key on the ECM triggers the fuel pump thru a relay but if the ECM doesn't see crank rotation it shuts down the fuel pump after a few seconds.
I wonder what fuel PSI is needed since the direct injection engines have the "high" pressure fuel pump powered by a lobe on the cam shaft?
I think I would ask the same question over on LS1tech.com.
Quote:
Originally Posted by Joyridin View Post
I have mine set at 65psi, but it was originally at 58 psi and ran fine. I do not have turbos or anything.
thanks for the replies, I reworked my harness and have the wire for the pwm control but had not sorted out if it could be used to control just a relay. My ls swap does the same thing, key on it will prime then if or when the engine dies it will shut off. That was the ease and safety I was looking for. I know this is not the best way but it seems to work. I didn't want to just wire the relay up to the key on switch mainly for safety.
I am still aways out on getting this all together as it is a full restore on a 1971 Camaro.

Thanks again,
Dave
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1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap
1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?)
"A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome".
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