Return line question

[Mike25th]

I have a question I have a 72 lemans with ac. I noticed that there is a 1/4 return line on my existing sending unit that goes to my fuel pump.
I am installing a fuel regulator with return line can I Tee into the existing 1/4 return line that goes to the fuel pump since it goes to the fuel tank or do I need a dedicated return line.


Thanks for any info

 

[melsg5]

Why are you installing a regulator?

 

[avell007]

If your putting fuel injection on there , no you can't use the 1/4 line the fuel pump has to much volume you need a 3/8 return. If your just using a carb with electric fp buy one the delivers 5-7 psi or use a holly dead head regulator no return needed.

 

[Mike25th]

I am running a carburetor. I am having problems with vapor lock so want to run a return line to help with some of that problem. Cold starts are fine 20-30 min after the car is off has a hard time starting.

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[melsg5]

You already have a return line and reducing pressure with a regulator doesn't cure vapor lock, which I doubt you have if 20 to 30 minutes after shutoff you have a problem.
Need more information about the car. Any modifications? If so what? Is this car new to you and if so how do you try to start the car when warm, just turn the key or slightly step on gas peddle and then turn the key

 

[Mike25th]

No mods car is stock. Runs very well otherwise. I do slightly step on the gas when warm before I start it.
I was also thinking the charcoal canister was removed a long time ago, could I use that as a return line and use a vented gas cap instead?

Thanks for the response

 

[melsg5]

No mods car is stock. Runs very well otherwise. I do slightly step on the gas when warm before I start it.
I was also thinking the charcoal canister was removed a long time ago, could I use that as a return line and use a vented gas cap instead?

Thanks for the response

You have a return line and the you don't need a regulator or 2nd return line.
What was done to the line from the gas tank to the charcoal canister, plugged, left open, a filter to prevent dirt? I have a 71, no canister, filter on end of line, no problem starting.
Have you started with basics? Have you checked the points, cap and rotor? Have you checked plug and coil wire resistance? Have you checked dwell angle and timing? Have you removed the air cleaner after 20 to 30 minutes and looked down the carburetor throat for dripping gasoline.

 

[Mike25th]

You have a return line and the you don't need a regulator or 2nd return line.
What was done to the line from the gas tank to the charcoal canister, plugged, left open, a filter to prevent dirt? I have a 71, no canister, filter on end of line, no problem starting.
Have you started with basics? Have you checked the points, cap and rotor? Have you checked plug and coil wire resistance? Have you checked dwell angle and timing? Have you removed the air cleaner after 20 to 30 minutes and looked down the carburetor throat for dripping gasoline.

I just have a filter screen at the end of my line where the charcoal canister use to be. It has HEI distributer new plugs and coil. I will try to check the air cleaner after running for dripping gas.

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[melsg5]

I just have a filter screen at the end of my line where the charcoal canister use to be. It has HEI distributer new plugs and coil. I will try to check the air cleaner after running for dripping gas.

So the car is not totally stock, 72 didnt come with HEI. Do you know what the initial timing is set to? What carburetor and intake manifold?

 

[avell007]

Pontiac hard starts when hot I personally have had in the past , stretched timing chain , bad starter , bad cable, carburetor bowl porous leaking when hot into intake, carburetor getting to hot , now these are things after the basics are checked. Try holding gas pedal to floor when hot see if that helps.

 

[Mike25th]

Will do thanks for the tip