Dante7

Hey guys I have 75 L-82 Vette and I am having a few problems again. I was looking under the hood today and saw a few things the previous owner had hid. The Return line for the fuel on the passenger side is disconnected. When I traced the lines coming off the fuel pump one goes from the main line in from the tank to the pump and the other comes off the pump and goes to my fuel filter and then too the carb. So where should the other line hook to? On the driver side of the car there is a metal line that looks to be for full that is just not hooked to anything right next to the distribution block for the brakes after tracing it back it runs along the frame and then into the side of the fuel tank on the drivers side. Can anyone explain what these are for?

A88FXRS

@ Fuel Pump Large Line Feeds Pump From Tank, Small Line Returns To Tank From Pump. On Driver Side Steel Line, Other Than Brake Line, Returns From Vapor Canister To Fuel Tank

Dante7

Alright well what do i do with the line on my driver side cause I have no vapor canister. And if I hook up the return line to the pump like it should where does the carb get its gas from?

A88FXRS

Cap The Driver Side Line With A Rubber Boot. Your Fuel Pump Should Have 3 Ports. Steel Line From Carb Is The Pump Feed To Carb. Other Two Should Each Accept A Rubber Line. Hope This Helps.
Paul

96 Lt4
87 Conv
74 383
69 427

noonie

You can either cap off the cannister line near the master cylinder or leave it open to act as a tank vent. If you do the latter, keep it up as high as possible on the firewall.

VETTE-DUDE

Dante7

Wow excelent explanation and I loved the pictures I shoudl be able to fix things easily now tomorrow thank you very much...

BKbroiler

You might have an aftermarket fuel pump which does not have the fuel return connection. If so, just plug the return line.

Red 69

Lotsa good info here, but I don't think all the dots are connected. Since you don't mention what fuel pump you are using there are different scenarios. The pump pictured is a stock style pump and has a nipple for the return line. If you have an aftermarket pump, you could leave the return blocked off, or buy a nipple to connect to the return line. This is assuming the model you have has a port for a return. The return line keeps cool fuel constantly supplying the carburetor. If you block it off, and later become stuck in slow traffic, there is a greater chance of experiencing vapor lock. If this happens, you should know why and the remedy. Most changes from stock have consequences and need to be thought through to avoid developing problems.

Peterbuilt

The line from the vapor canister to the carb is cut off, where on the carb should it be attached? To the fitting just above the fuel inlet?
74 Stock Q Jet on stock 350 auto trans. Thanks Pete.

redwingvette

THis is for a 73, I think the 74 is similar

corvetero

Old thread, just wondering the same on my 74 and Holley 4160 though.

DUB

YES..the diagram in POST#11 will work for you.

Your charcoal canister more than likely ONLY ahs three hoses gong to it. One from the vapor line coming form the tank. Which you need to check to make sure it is not plugged up. And the other two hoses goes to the carb. The small hose going to the carb goes on a PORTED fitting on the carb and NOT...REPEAT NOT on a constant vacuum source.

There is a PCV valve in the valve cover that has a 'T' made into it as this diagram shows.

DUB

corvetero

Thanks, my canister is not that way as it only has 2 ports on top, one goes to the tank and the other one it supposed to go the carb, however my carb is a Holley 4160 (is not the original one) hence I don't know where to plug the hose in the carb. Wondering whether I can plug on the PCV by installing a PCV with the T.

DUB

I would NOT put the hose that goes to the carb to the PCV. This will cause for a constant serious vacuum being pulled on your gas tank vapor line at all times. Even when you are sitting there idling.

The line that goes to the carb should be connected to a PORTED vacuum port. So it ONLY pulls vacuum when you are OFF IDLE and accelerating.

On the charcoal canisters that have three hoses. They are still using a hose that is attaches to a PORTED port on the carb as the CONTROL. So when you are off idle...it allows fuel vapors to be pulled into the carb. But when you are idling...it is not. And when this 'CONTROL' hose that is attached to the carb on the ported fitting is allowing vacuum to be used to control the valve in the charcoal canister. Then the hose that is attached to the PVC will pull vapors.

Hopefully that makes sense.

DUB