fuel press regulator problem
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Pro
Joined: Jul 2006
Posts: 557
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From: chiefland fl
fuel press regulator problem
Hey guys, to make a long story short i did an eng swap, went from efi to carb want to use the stock in tank pump, bought a holley 803bp bypass regulator, and the press pegged my gage over 15psi and fuel bubbled though my carb all over! i tried every which way to adjust it, think its defective, this worked great on my friends 90 camaro, (same part number regulator) i have buddies that dont even use a bypass type regulator and it works great, do i need a bigger return line for the vette than the camaro? it does seem alittle restrictive, (but that kills my other theory with my frineds not even using the "bypass" reg on their late model monster trucks) i think i got a bad one, just want to be sure and talk to the "pro's" here! thanks, bb
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
If you remember, the reason the pump pumps more fuel than you can use is because on the later carbed cars, there is a bypass on the fuel pump to divert unused fuel back to the tank to prevent vapor lock.
Your pump in the tank does that with the stock fuel regulator.
Enter your carb.
It only needs 7 psi to run efficiently. you have a pump capable of running 50 psi.
IF I were you, I would experiment with a return line plumbed into the pressure side of your fuel line with a fitting soldered or brazed shut on the middle fitting of a "t" fitting. I mean the return line is already being used, use it more.
Drill a hole 1/8" in the brazed fitting, and let it return back to the tank by using another "t" fitting on the return line Hook everything up as a temporary setup using high pressure rubber hose.
2 things, 1, this will prevent vapor lock, and 2, help out that poor overworked regulator that you put in.
If you still can't control the pressure, drill the hole 5/32", if better, drill the hole 3/16". If that doesn't work, make it 1/4"
get it? Make a permanent setup if this fixes the problem.
the regulator was only supposed to work with 8-10 psi, and now it's 5 times that amount.
Your pump in the tank does that with the stock fuel regulator.
Enter your carb.
It only needs 7 psi to run efficiently. you have a pump capable of running 50 psi.
IF I were you, I would experiment with a return line plumbed into the pressure side of your fuel line with a fitting soldered or brazed shut on the middle fitting of a "t" fitting. I mean the return line is already being used, use it more.
Drill a hole 1/8" in the brazed fitting, and let it return back to the tank by using another "t" fitting on the return line Hook everything up as a temporary setup using high pressure rubber hose.
2 things, 1, this will prevent vapor lock, and 2, help out that poor overworked regulator that you put in.
If you still can't control the pressure, drill the hole 5/32", if better, drill the hole 3/16". If that doesn't work, make it 1/4"
get it? Make a permanent setup if this fixes the problem.
the regulator was only supposed to work with 8-10 psi, and now it's 5 times that amount.
Last edited by coupeguy2001; Mar 22, 2009 at 07:47 PM.
