I need a new fuel pump in my 91 305 TPI but I will be doing an engine swap in the near future. Instead of using a stock type fuel pump, can I go ahead and switch to an external electric fuel pump/filter/regulator setup, or will this not work using the stock computer? I just didnt want to have to use a stock type fuel pump now and then this winter take the tank back down to put a sending unit in for an external pump. Seems like a waste of time and money. What do you think?

 

what are u swaping to? the pump and regulator are going to be different if you go to something that takes less psi.

 

I will be going from a 305 TPI to a 383 carburated. I figured I could just set the regulator to whatever the 305 needs, then bump it up when I swap engines. Will the external pump work with the stock computer though or do I have to wire it seperately? If I do wont this mess with the way the computer monitors the engine?

 

the computer doesnt care whats going on with the pump i dont think. all it wants is a pressure probably. your problem though is tpi wants like 45 psi and the carb wants like 5-7 psi. some one else can correct me but i dont think it would be good to get an external that puts out that much psi and then regulate it down to 6. not to mention the 6 psi pumps are much cheaper. whats the stock pump going to cost like 35 bucks. you'll spend too much on an aftermarket pump that can supply the tpi.

 

thats a good point you have there. Asuming that the pressure difference is correct I guess it would just be better to go with the stock pump for now. Can anyone verify this?

 

Pressure difference should not matter, as long as you use a Bypass type regular. Mallory makes a 3 port bypass (PN 4309) for fuel injection pumps to carbs. I just had my 383 running few weeks back for the first time. I used my 350 FI pump to the 383 carb using the mallory regulator. Basically it'll let you take in 40+ PSI of pressure adjust that down to 3 PSI and up and then it puts all the rest back into the return line that you can just hook like your fuel injection does now. Definitely don't want to use a regular dead head regulator or you'll be spiking hurting the carb and burning out the pump.

As for wiring I think the only thing that pulles from the ECM to the pump relay is the ground and 12V switched source. I got mine to run fine by splicing into the relay a 12V wire, that I plan on making run-hot only.

I would just go with a replacement one in the tank, unless you want to pull the one out and put a pickup tube in instead. Usually when pumps die they flush out bits into the gas line, and I wouldn't try putting an inline behind a dead one from the debris and extra pressure for it having to pull through a dead pump. And of course you can't just go to an external carb pump if you still want to run your tpi right now.