350 tbi to 383 carb swap

[Lawrence Taylor]

Hey guys. Ive got a 89 eclb k2500. Just got a new blueprint engine 383 installed, cut the ecm out, re wired stock fuel pump and relay, and put a fuel psi reg in. Everything is working how it should but i am getting excessive psi build up in the tank. Just wondering if that could be caused by to much fuel return to the tank? And is there a way to remove the stock in tank pump from the sending unit, install a ext pump and get rid of the excessive psi build up in the tank?

 

[Schurkey]

Perhaps a moderator will move this thread to LSX + Carb Swaps.

How is the tank vented? Did you gut the charcoal canister, too?

You can't build pressure in the tank from the fuel return--you can't return more fuel to the tank than you've pumped out to begin with.

I have no idea why you'd remove the in-tank pump for a failure-prone external pump. The major manufacturers put the pump in the tank because that's where it's easiest to prime, and runs coolest. External pumps are harder to keep running properly.

 

[thatclappedsilverado]

Like schurkey said make sure the vent for the tank is still okay. I removed My charcoal canister when i swapped to the 96-99 washer res. I still run the factory pump with a return style regulator and havent had any problems at 6 psi for the last year. The electric pump will be more reliable like he ssaid aswell.