I searched everywhere here and on the net and can't get definate answers.

The stock TBI fuel pump is in the fuel tank. I'll be running a Holley 600CFM Vac Sec. I know Mallory makes a $80 pressure regulator (from Summit) with a return line to the tank.

I was told that, time and time again, using this regulator causes the in-tank electric pump to die. Is this because of the 15psi down to 6psi drop or because the pump has to be run constantly while the engine is running (no ECM)?? or is this BS?

This speed shop owner (I was willing to buy the Mallory unit here) says the best thing to do is take out in-take pump and replace with a copper tube bent 90 degrees at the bottom and facing the rear of the tank, then use mechanical type pump.

What about the fuel-level device? I've heard it's conjoined to the electric pump. Can that stay without the pump? Amount of fuel left is quite important to know.

I really don't want to take the tank down (never done it). But I don't want to get stuck and need a tow either. What is the proper way to get gas to this engine?

 

It's using a regulator without the return, dead-heading the pump, that burns out in-tank pumps (they rely on constant flow to cool them). Those pumps run constantly with a TBI system, which includes a return, so why would doing the same, at a lower pressure, burn it out with a carb?

The pump can be removed from the gas gage sending unit as he stated. But, an in-tank pump pushing fuel out of the tank is superior to a pump up in the engine compartment trying to suck fuel out of the tank, so I'm having a hard time imagining why you would want to do that.

Yes, the in-tank pumps will fail. When that happens, then perhaps a lower-cost alternative would be to convert to a mechanical on the engine. Until then, though, I'd go with the electric & reg.

 

I know two people who have had major tuning issues trying to run a regulated in tank pump, swapped the pump for a mechanical and the cars/trucks ran fine.

 

When I swapped from TBI to carb, I dropped the tank, yanked the stock fuel sending unit, replaced it with a sending unit from an older 3rd gen (that came with carb), and then ran a mechanical fuel pump. Everything fit perfectly and the gas gage works great. I think I paid $10 for the sending unit (at a junk yard).

 

Thanks for the info guys, really does help me with my decision.

I would assume the regulator wasn't putting out a steady 6psi?

I like the option of the "older F-body" gas level sending unit, problem is boneyards in my area have like a $100 min on even a door handle. And the GM dealer would certainly give me sticker shock.

I guess if I'm going to throw $80 at the car I might as well make it easy on myself (for now) and buy the Mallory return to tank regulator.

Does the elec. pump come on in the run position and stay on, or do I have to wire it (ECM is bye-bye)?