[Chris_K]

Ok, I know there's other posts on this topic but I'm still confused. I have a brand new 383 going into My 74 Nova with a hi-volume mechanical fuel pump. the original fuel system had three lines - one from the tank to the pump (then to carb), a second smaller line from the pump back to the tank. and a third line from the carb to the charcoal cannister and then back to the tank. Which of these lines can I elliminate? My new fuel pump only has provisions for one line from the tank and one to the carb. All original emmisions equip has been removed.

Thanks for the help!

[Siggy_Freud]

Well you can eliminate the charcoal canister line if nessesary. You also dont NEED a return line to the tank but if your using a high volume pump it would probably be a good idea.

[jimdavis]

Originally Posted by Siggy_Freud

Well you can eliminate the charcoal canister line if nessesary. You also dont NEED a return line to the tank but if your using a high volume pump it would probably be a good idea.

He said his pump only has provision for a line from the tank and a line to the carb so he can't hook up a return line unless he uses a bypass regulator and plumbs a return line from there. Which I agree is a good idea.

Before I changed my setup to one with a return line, I was plagued with vapor lock problems. I am using a high volume electric pump, not a mechanical one so I am not sure if the same conditions would exist.

[Chris_K]

Ok, so I can loose the charcoal cannister but I should keep the return line with the use of a regulator, right? And this is to make sure that the system can breathe well enough? thanks for the help!

[pmeisel]

On jeep the return line to the tank is tee-ed out of the fuel filter. This is primarily to prevent any possibility of vapor lock which was a problem on some of those vehicles. You could do this without much trouble.

[jimdavis]

Originally Posted by Chris_K

Ok, so I can loose the charcoal cannister but I should keep the return line with the use of a regulator, right? And this is to make sure that the system can breathe well enough? thanks for the help!

OK....part of what I am going to say is conjecture on my part so I am not positive it is totally accurate. But I think what happens with a high volume pump is that at other than full throttle conditions it is trying to pump way more fuel than is required. With the pump trying to push more fuel than is needed, my thinking is that this heats up the fuel, potentially promoting vapor lock.

With a bypass regulator, the excess fuel is just shunted back to the tank keeping it cool and eliminating any possible vapor lock problems.

As I said earlier, this is probably more true with a high volume electric pump than a mechanical one because a mechanical pump is tied to engine speed whereas an electric pump puts out the same no matter what the engine speed is.

[onovakind67]

[QUOTE=Chris_K]Ok, I know there's other posts on this topic but I'm still confused. I have a brand new 383 going into My 74 Nova with a hi-volume mechanical fuel pump. /QUOTE]

What fuel pump are you using? The pump will only be as good as the supply line will allow, so I would consider replacing the stock line with something larger.