My brother doesn't have internet, so I'm trying to help him. He has an 88 Firebird with 350 4-bolt main, port-matched, MSD ignition and Edelbrock 750cfm carb. The car originally had V6 EFI with electric fuel pump. He disconnected the electric fuel pump (cut the wire) and put on a mechanical pump, rated around 70GPH, I think.

The problem is it bogs down and stalls when he "gets on it hard". He is wondering whether the electric pump apparatus might be slowing down fuel delivery, although it is disconnected from power and not operational. Any ideas would be greatly appreciated!

 

Not a good idea to pull through a electric pump. I have heard that sometimes it works sometimes it don't.

Was the electric pump bad? If not I would have used it with a regulator set to 6psi.

He is going to have to either drop the tank and get it out or get the wire hooked back up and use a regulator.

Hope this helps

 

The mechanical pump will regulate pressure. As long as it's a return-type mechanical pump, just reconnect the electric pump. Some cars came from the factory with a similar setup of two pumps.

 

I believe the V6 ECM controlled the electric in-tank electric pump. If it is out of the loop, it won't properly control the fuel pump. A properly set-up electrical circuit, including an oil pressure switch, would have to be run to the pump.

As for the mechanical pump regulating the pressure with an electric pusher back by the pump, it should work - if, as stated, a return-style stock pump is used. I've contemplated doing this but haven't gotten to it yet.