Fuel tank outlet
And to the OP, every 1984 Olds 307 used fuel return and a three port pump. This is why you should never trust listings in an aftermarket catalog. The original factory P/N is 6471473. Carter M6109 and Delphi MF0006 are two available aftermarket pumps.
The fuel pump has nothing to do with the charcoal canister (it just captures fumes from the gas tank to burn off, it is not attached to the fuel sender, but to vents outlets on the gas tank). Read Joe's post again, the three port fuel pump, in essence just recirculates fuel between the tank and pump and the third port goes to the carb. The fuel pump lines run back to the sender.
Thanks guys but I think we got a little off track. I wasn’t asking about the pump, I understand that. It’s the third line on the sender ( in the tank) that I don’t know what it’s for. Usually there’s just a supply and return.
The fuel pump got brought into the discussion because it is a whole lot easier to look under the hood at it to determine if you have a return back to the fuel tank, which determines whether you need a one or two outlet sender.
Yes. All 1984 307 Cutlass built for U.S. sales used a 3 port sender from the factory, one for the fuel supply, one for the charcoal filter vent line (which on your H/O, runs to the driver side up the frame rail, runs across the front crossmember, and then to the charcoal canister on the passenger side), and one was the little return line from the fuel pump. Two ports only had charcoal filter vent and fuel supply. But with your H/O, you don't have to worry about 2 port senders. That's why they were talking about the pump. That little return line was only used on 3-port setups so it was easy to tell which type you had just by peeking at the fuel pump without getting under the car.
Early cars had the vent lines routed directly from the tank and not part of the sender. Later cars incorporated the vent line into the sender. A two port sender for a 1969 DOES have fuel return. A two port sender for a 1984 does not.
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