Fuel Injection Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72ChevyCheyenne · 10-09-2002, 03:18 PM

How do you set up the return fuel line on a fuel injected engine? I am planning on installing a 502 Ram Jet with a Blazer tank in the back. I want to mount the electric fuel pump close to the tank. Does the return line come off the injector or the pump?

jmil1974 · 10-09-2002, 03:42 PM

Most (all I have seen) return lines come off the fuel rail and back to the tank via a separate line (should be same size or LARGER than the supply line). If there's no bung for a return line on the tank, Moroso makes a return line kit for the filler hose that I hear works pretty well. Make sure to use an internal pump or at least get the external pump lower than the tank sump to avoid early pump death or vapor lock. Internal are best for siphoning reasons as well as lubrication and cooling reasons. I know some off-road guys who wire in 2 external pumps with a switch in case they have a failure they can flip a switch and drive home. Use hard lines if possible though stronger EFI-rated rubber lines are now readily available at most parts stores.

10-09-2002, 03:18 PM	#1
72ChevyCheyenne Registered User Join Date: May 2002 Location: Woodstock, GA USA Posts: 300	Fuel Injection Question How do you set up the return fuel line on a fuel injected engine? I am planning on installing a 502 Ram Jet with a Blazer tank in the back. I want to mount the electric fuel pump close to the tank. Does the return line come off the injector or the pump? __________________ Bill Durham http://home.attbi.com/~bulldurham 72 Cheyenne Restoration in progress Currently: frame sand blasted and powdercoated, Inline Tube brake and fuel lines, Blazer tank in rear, Holley Red electronic fuel pump, Eaton posi with 3.42 gears, 2 1/2" drop front spindles, 4" drop rear springs with adjustable panhard bar, KYB shocks, ZZ 502/502 GM Performance crate engine, Zoops brackets and pulleys, Vintage Air, dual electric fans, Ram Air II hood and late model sport side bed.

10-09-2002, 03:42 PM	#2
jmil1974 Ain't we cute? Join Date: May 2002 Location: Friendswood, TX Posts: 700	Most (all I have seen) return lines come off the fuel rail and back to the tank via a separate line (should be same size or LARGER than the supply line). If there's no bung for a return line on the tank, Moroso makes a return line kit for the filler hose that I hear works pretty well. Make sure to use an internal pump or at least get the external pump lower than the tank sump to avoid early pump death or vapor lock. Internal are best for siphoning reasons as well as lubrication and cooling reasons. I know some off-road guys who wire in 2 external pumps with a switch in case they have a failure they can flip a switch and drive home. Use hard lines if possible though stronger EFI-rated rubber lines are now readily available at most parts stores. __________________ 69 C10 2WD LWB Fleet 350/350 power front disc conversion (6 lug disc kit from gmcpauls) and new engine, PS, A/C, fresh fluids, SHE DRIVES! FOR SALE $3900

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