[Chirp08]

My friend recently did a TPI to carb swap on his 350, went from a stock TPI system to a performer RPM, edelbrock 750cfm carb, mallory pressure regulator, MSD distributor. The pressure regulator has the pressure set right at the desired 5.5-6psi. When he turns the key the fuel pump (stock electronic in tank pump) it primes the system and he gets the desired 5.5 psi. Than when he starts it hte pressure immediately drops to around 3 psi, and the car wants to cut out, sometimes it goes to 0psi causing it to stall.

Is this an issue with the computer controlling the fuel pump, if so can the pump be hardwired to bypass the computer completely?

A mechanic said the fuel pump is going bad, but that makes no sense, with it being electric wouldn't it either work or not work, off or on? I don't see how it can "sometimes work" like he is implying..

He would like to avoid converting to a manual fuel pump mainly because he cant afford to do that, and it means dropping the gas tank to get to the old pump.. its not exactly an easy swap..

 

[Dave427]

I think the mechanic is right . Make sure you are not dead heading it . Does the regulator you are using have a by-pass? If not that might be making it overheat.

Dave

 

[cv67]

I think the mechanic is right . Make sure you are not dead heading it . Does the regulator you are using have a by-pass? If not that might be making it overheat.

Dave

Agreed, especially if it is a factory TPI type pump. Those were designed to push 43 lbs or so, regulating it down that far may be too much for that pump but Im no expert.

 

[Chirp08]

its got a bypass running back to the tank, its basically 4 openings in a cylinder, than a single opening that has the proportioning valve, the way you hook it up for this setup they say on teh thirdgen board is to run a line from the opening with the valve to the carb (usually this line gets run to the fuel return), than hook up the return and the feed lines to 2 of the 4 openings, plug the other 2.

For some reason this just doesn't seem right to me but they swear by it and its how "everyone" apparently runs it.