66steve

Okay, I've tried to search posts to help me but can't quite find what I need.
Here are the facts:
66 4 4 2
Hasn't run in aprox 10 years
Previous owner ran car with an electric fuel pump...3/8 line direct to carb...no return line. he felt he was having "vapor lock" problems, hence the foil wrapping the main line.
I'm to the point of going throught the lines/tank/return lines/vent lines.
Hope you can see from the pic's, there is an out line going into the punp...a vent line from top of tank on passenger side that loops through the trunk and persumable ends under the trunk near the wheel well(just like shown in the CSM)....can't see it yet. and the original return line runs back parrallel to the supply line but isn't connected to the tank.
I'd like to give it a try with the new mechanical pump I've installed. BUT, don't see where i dump the return line into? Might decide to try the electric pump later...but even so, he was running the electric without a return line and I suspect he had problems because of that....soooo, even with the electric, shouldn't it still use a return line?

Dropping the tank isn't too big a deal, but even so, I don't think I'm seeing what is shown in the service manual....not sure.
Anyway, love to hear what you think.


s

oldcutlass

The mechanical pump had a return line built into it and the outlet ran back to the tank. There are no provisions for that with an electric pump. With that said there are ways to use the electric pump with a pressure relief to route the fuel back to the tank.

joe_padavano

The whole point of a return line is to allow the mechanical pump to recirculate part of the hot underhood fuel back to the tank to cool off. The electric pump is less sensitive to this. You can simply cap the return line going to the tank and run the pressure line from the electric pump to the carb. Just be sure the pressure isn't too high - that can cause flooding.

66steve

Thanks for your help.

Joe, What you've described is exctly as the car came to me, so that's fine.

If I wanted to switch back to the mechanical pump, the return line goes all the way back to the tank....how come I'm not seeing a fitting for a return line? Am I missing something or is its location going to become evident when I drop the tank?

Thanks again for your help....and by the way, you gave me advice last month about replacing the front cover with the oil pan on....that went fine too, so thanks again for that.

steve

joe_padavano

Steve,

Something has been changed on this car (despite the fact that the tank and sender look like they've been there for decades). The sending unit for a car with fuel return will look like this:

66steve

Gotcha!

That's what I was looking for...that's not the sending unit I'm looking at....question answered!

Thanks

s

joe_padavano

This is the sending unit on your car and it only has one line - no return line.

EDIT: as I look more closely, it appears that the return line might have rusted off.