One Bad 74

Can I plug or block off the return line from the fuel pump to the tank? If so, where should I plug/block it? The car is a 74 L48. Thanks for your help!!

John

One Bad 74

ttt

Stewart's74

Yes, you can block it off. A number of forum members use pumps without a return line. Why not block it off at the tank.

norvalwilhelm

I do not run a return line. I run twin Holley pumps with a single line to a holley regulator. I have run this combination for 13 years without a problem. I do run a total of 3 fuel pressure gages so I would know if there was a problem.
Stewart's74 why not block it off right from the pump and not have the return line pressurized all the way back to the tank? More chance of a leak?

Matt Gruber

if yours has a big hole in the hood like norval's, block it off.
i found in FL in a traffic jam it would vapor lock in 10 minutes. Hooked it back up, no problems!

One Bad 74

I was hoping I could plug it off at the pump but I was concerned that it may cause problems. I have completely removed the return line because it was leaking. The pump is new but maybe I should go buy another pump without a return???

John

Stewart's74

Norval, I was assuming the line wasnt even attached to the pump.

cardo0

Looked in my Chevy shop manual and that line was called a vapor return line . Now you could stick some flex fuel line on that pump vapor fitting and run the car for a short while to observe any fuel/liquid flowing out of that line. If not, just a short run up to the aircleaner housing with flex fuel line would save ya from installing a new pump - not the cleanest part to replace. I would hate to have to replace that return line let a-lone the fuel line.

I'm in process of installing a Carter street/strip pump (~$50) without a connection for return line - only supply from tank and output to carb. Had to unscrew and rotate base for alingment. Can't report on performance yet but it fit up just fine. :D

Jughead

I don't have a return line on my '70. LT-1's didn't have return lines and I don't know if mine started out life as an LT-1 or not....doubt it. Previous owner must have removed the return line, but there's also no provision at the tank for a return line. :confused: I've been driving her like that for over 3 years with no side effects. :D

norvalwilhelm

Looked in my Chevy shop manual and that line was called a vapor return line . Now you could stick some flex fuel line on that pump vapor fitting and run the car for a short while to observe any fuel/liquid flowing out of that line. If not, just a short run up to the aircleaner housing with flex fuel line would save ya from installing a new pump

cardo0 I would be very causious about running a flex line from my return line to the air clearner. If fact I would not do it. What about fire. A backfire through the carb while this line is dumping fuel vapors into the air cleaner could be disasterous.
I would not hesitate to totally block it off at the pump but like Matt said it could vapor lock. I run electric pumps right at the tank that push the fuel not suck it like a stock pump. A new pump without the return line wouldn't make a difference.

Matt Gruber

my lines rusted out.
i bought 20' rolls of GOODYEAR fuel hose. Covered the hose near the header with header wrap.
For just the return line you could buy a 20' roll of 3/16 brake line. it is bendable enough to fish thru there.
Until you get the new line plug the pump. if it quits in traffic, pop the hood. in a few minutes it should restart. Prop open the hood with a soda can. TX gets a little hotter than the north :lol: