I have a question about fuel pumps. I have a 2.8/v6 mpfi I want to swap in a carbed sbc. My fuel pump quit, can I just leave it in the tank and add a mechanical fuel pump at the engine or do I have to replace it?

 

You likely won't be able to pull enough fuel through the old pump, you'll need to remove it then add a extension pipe to the sending unit to extend it to the bottom of the tank. I did the same and put a universal sock on the end.

 

Thanks that is what I afraid of. So gotta pull tank anyway.

 

You will most likely be glad you pulled the tank. There's a good chance that old pump and housing have corroded. So you might as well make sure you fuel tank is nice and clean before you put in your new motor. Me and my dad pulled the pump on a 88 recently and the tank was full of rust from the old fuel pump.

 

If you replace the old V6 pump with a TBI pump, it will supply the expected low pressure your carb is expecting. You'll still need a regulator, but can do away with the mech pump up front

 

Can't say I agree with all of that. Pressure is a function of resistance to flow and the power capability of the pump motor. The TBI pump puts out less pressure because the motor isn't as powerful. A TBI pump will be taxed to deliver sufficient flow at carb pressure beyond a certain horsepower level.

If you're going to drop the tank, put in a good pump. A TPI replacement, or the commonly-used Walbro 255 is a better choice, IMO. Even the MPFI pump is better than the TBI unit.

The pressure regulator needs to be a return-type to keep flow going through the in-tank pump constantly. If you use a dead-head type pressure regulator, you'll burn the pump up.

An in-tank pump with pressure regulator is a much better fuel delivery system than an engine-mounted mechanical pump.

 

Thanks I decided to stay with a in tank pump. Still deciding on which one now.