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post #1 of 7 (permalink) Old 04-20-2018, 07:07 AM Thread Starter
 
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2 vent v 1 vent

I have a 1968 GTO with AC. I haven't had the car long and just started working on it. When I raised the care I noticed there were two lines adjacent to the fuel pump. One (smaller in diameter) was left unattached to the fuel pump and the larger one was attached to the fuel pump. The fuel pump only had 2 fittings, one from the tank, the other to the carb. I checked the tank and sure enough there was a feed line and return line. I did some checking and it seems AC cars had return lines. Can anyone tell me why the AC cars have the return line and also would it hurt if I didn't run a return line (seems you can find new tanks with the filler neck for single lines and not so much for double lines)?

Dean
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post #2 of 7 (permalink) Old 04-20-2018, 03:21 PM
 
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Originally Posted by Akhuntr View Post
I have a 1968 GTO with AC. I haven't had the car long and just started working on it. When I raised the care I noticed there were two lines adjacent to the fuel pump. One (smaller in diameter) was left unattached to the fuel pump and the larger one was attached to the fuel pump. The fuel pump only had 2 fittings, one from the tank, the other to the carb. I checked the tank and sure enough there was a feed line and return line. I did some checking and it seems AC cars had return lines. Can anyone tell me why the AC cars have the return line and also would it hurt if I didn't run a return line (seems you can find new tanks with the filler neck for single lines and not so much for double lines)?

Dean
My 68 non A/C car has two fuel lines. (Supply and return). They run from the sending unit to the pump. The sending unit and pump are available with or without the return line fitting. The tank is available from Ames Performance.

Hope this helps.

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post #3 of 7 (permalink) Old 04-20-2018, 08:36 PM Thread Starter
 
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The reason I was asking is the Fuel pumps are listed as a non AC and with AC. The with AC has the return line and the non AC pumps don't have the return line.
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post #4 of 7 (permalink) Old 04-21-2018, 01:18 AM
 
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The reason I was asking is the Fuel pumps are listed as a non AC and with AC. The with AC has the return line and the non AC pumps don't have the return line.
I am not sure why they list the pumps that way...
I believe all T8 (8 cylinder Tempest) had two fuel lines (supply and return) while T6 only had a supply line.
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post #5 of 7 (permalink) Old 04-23-2018, 08:39 PM
 
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They're listed as AC and non AC due to the return line back to the tank. It helps a harder working AC car keep the fuel cooler by recycling it back to the tank as needed.
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post #6 of 7 (permalink) Old 04-24-2018, 10:20 PM Thread Starter
 
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Vapor Lock

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Originally Posted by tjs72goat View Post
They're listed as AC and non AC due to the return line back to the tank. It helps a harder working AC car keep the fuel cooler by recycling it back to the tank as needed.
I spoke with a friend of mine today that suggested that very same thing.

Thanks
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post #7 of 7 (permalink) Old 04-25-2018, 09:31 AM
 
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That is fine, but 1968 non-A/C (V8) cars had the return line also.

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  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO Exhaust, Suspension, Alignment, Fuel Tank and Brakes.

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