71oldsS

I am so happy to get my motor from rebuilder tomorrow and I have to get all new sub-assemblies. I have a 71 cutlass S with 350, and I don't know which fuel pump to get. Am I correct in ordering the one with 3 lines? Thanks in advance.

MDchanic

How many lines are on the car?

- Eric

71oldsS

I am guessing 3. 1 from gas tank, 1 from canister and 1 to carb. correct? Old fuel pump discarded during rebuild.

MDchanic

The fuel pump does not pump fuel into the charcoal canister.

There are either one or two fuel lines running along the frame from the tank to the pump, and there may also be others involved in the evaporative emissions system.

I generally throw all of the evaporative stuff away, so I can't comment on how it's supposed to be connected.

In '71 some cars had return lines and some didn't, depending on engine size, options, and emissions systems (CA vs everyone else). I do not know exactly which cars got them and which didn't. By the mid-seventies, they all had them, but that doesn't help you in 1971.

Three lines is a reasonable guess. You can always cap the extra one if you need to.
But don't connect the return line to the charcoal canister. It would be bad.

- Eric

Octania

Mainly the return line to the tank was for AC +/or HD Cooling cars. Sends some of the fuel back to the tank so that relatively cool fuel is always near the engine, not boiling fuel = vapor lock. If you have AC or HDC then use the 3-line pump. If you see two lines on the frame to/from the fuel tank, then you have the lines for it. worst case, if you get the 3 line pump but do not have the 3rd line on the frame, just plug the 3rd nipple at the pump and voila you have the 2-line pump doing what it should.

71oldsS

There are 2 lines, 1 goes to fuel pump and 1 to canister and then 1 coming back out of canister, where does that 1 go? Are saying I don't need canister? So it sounds like I need 2 line pump.

Allan R

Then you get the same as what's on there now. They are not saying you don't need the canister, they are saying it's THEIR preference to bypass it. Do what you think is right for your application. If you're goal is stock, keep and run lines to the charcoal canister. That's my opinion.

Allan R

the line routing to the canister is covered in the CSM and Assembly Manuals. Easy enough to look up. It's not confusing.

joe_padavano

Just so we're all clear, how many lines are bolted to the frame rail, two or three? Two lines are one feed to the pump and one vapor for the evap cannister. The third line would be fuel return and also goes to the pump. There is an outlet line from the pump to the carb and a cannister purge line from the cannister to the carb.

Allan R

^^^ this. Btw, it's the right side frame rail. Also if you're replacing the fuel pump you should also,seriously look at the rubber fuel line that connects the rear steel line to the front one. That rubber line passes though the front frame rail and is often overlooked. If it hasn't ever been changed, it's overdue.

71oldsS

Absolutely on the rubber fuel line. Got it all figured out now, thanks again for all the replies.