72 fuel return line

Reply Subscribe

Thread Tools

Search this Thread

Apr 23, 2018 | 02:01 PM

Davektm

Thread Starter

New User

Joined: Jan 2018

Posts: 21

Likes: 0

72 fuel return line

Hey guys,

I'm getting ready to reinstall my engine and tranny and sorting out all the lines. My truck has a fuel return line running back to the in cab tank, do I need the return line? I'm running an electrical pump if it makes any difference and have swapped out the old Holley 2 barrel for an edelbrock 4 barrel and can't remember where the return line came off the 2 barrel 😬

Any my help very much appreciated

Apr 23, 2018 | 03:08 PM

Brian1971f100

Posting Guru

Joined: Mar 2016

Posts: 1,412

Likes: 1

From: Barre Mass

That is a fuel vapor recovery line. It should go to a charcoal canister located in front of the passenger front spring on the inside of the frame rail. Should have had some sort of line that ran to the air cleaner or the intake.

Apr 23, 2018 | 03:08 PM

HIO Silver

Fleet Owner

Joined: Dec 2009

Posts: 20,678

Likes: 82

From: NorCal

Quote:

Originally Posted by Davektm

An OE 2V application won't have a return line with a mechanical pump.

A return line would be present (generally) with EFI or a carbed 4V application with a high-pressure electric fuel pump and by-pass fuel pressure regulator.

... we would be interested in more detail what electric pump you installed so we can provide better feedback. Pics are welcome too.

Apr 23, 2018 | 04:05 PM

Davektm

Thread Starter

New User

Joined: Jan 2018

Posts: 21

Likes: 0

It's an edelbrock pump that was on when I got it and ran with the two barrel. I've binned the charcoal filter and that could well be where the vapour line ran from. Is there any reason I can't just plug up the tank connection and ditch the vapour line?

Apr 24, 2018 | 03:31 AM

Davektm

Thread Starter

New User

Joined: Jan 2018

Posts: 21

Likes: 0

Having looked at this I may do away with the charcoal filter and vapor line and run a hose down the chassis to the rear of the truck with an inline breather like the one below

Apr 24, 2018 | 03:32 AM

Davektm

Thread Starter

New User

Joined: Jan 2018

Posts: 21

Likes: 0

Apr 24, 2018 | 07:54 AM

NumberDummy

Ford Parts Specialist

Joined: Nov 2006

Posts: 88,826

Likes: 784

From: Simi Valley, CA

1972 F100

Quote:

Originally Posted by Davektm

I'm getting ready to reinstall my engine and tranny and sorting out all the lines. My truck has a fuel return line running back to the in cab tank, do I need the return line? I'm running an electrical pump if it makes any difference and have swapped out the old Holley 2 barrel for an edelbrock 4 barrel and can't remember where the return line came off the 2 barrel ��

I see you live in the UK, but do you know where the truck was sold new?

1970/72 F100's sold new in California (CA) have the Evaporative Emission system (see pic below). Other states may have mandated it as well.

DSO code stamped on the 3rd line-far right of the Warranty Plate, riveted to the left door face below the latch. If the code is 71 or 72, it was sold new in CA

Click on pic twice to enlarge it. 9D653 shown at lower left is the charcoal canister.