Heavy Chevy89

I have a problem with my 1989 chevy caprice I did a motor swap from a 1994 lt1 5.7 350 9c1 motor, but Im having fuel issues. Ive been through 3 fuel pumps in a matter of 7 months. Its not the brand Im buying its just somethings not working out right. The first pump did great because it was fresh and new, all of a sudden it went from a normally buzzing sound to a high performance fuel pump buzzing sound at an idle, but when i actually drive it and try to put some HP to the ground she bogs like its not getting enough fuel through, but when im cruising it shifts and drives perfect only when i put pressure to the pedal does it bog, the same with the other two fuel pumps, yes Ive changed fuel filters and pumps, I havent messed with injectors, fuel pressure regulator, air fuel ratios, or fuel sending unit. Oh yea and another crazy thing is if i let the gas tank get bone dry and put fresh gas in it-it seems to get some of the power back but goes right back to doing the same thing.

cardo0

Yea, just replaced fuel pump myself - something like #5 (lost count). Car started, ran and drove ok but when i measured fuel press would drop at WOT. I also let the tank go bone dry and let the car stall out more than once. Now i think that is very bad on the fuel pump (even though at the time pretty funny as i was able to roll/coast up to a gas station pump).

U can always connect fuel press gauge at the fuel reg schrader vlv and tape the gauge to the windshield for a drive to watch fuel press.

Some thing i always suspect is the tiny o-rings in the fuel line quick connectors - they may wear after 20 some years of use. And i caught my fuel line on my new fuel filter was leaking - my fault but it looked good and felt good when i installed it so im sure it can happen to others. For some reason the LT1s seen to go through more fuel pumps as they age. New, the cars would go >100k mi with original pump, after that failure rate get much worse.

cardo

96capricemgr

iTrader: (1)

When electrical components repeatedly act up grounds need to be checked and rechecked.

ChevyOwner

What fuel pump are you using?
If you are using the pump for the 89 caprice I would guess that may be the problem.

Heavy Chevy89

Im not using fuel pumps for the 1989 model car Im using 1994 9c1 caprice fuel pumps. I tried this and that but nothing working. I came up with a few ideas over-night I could have a collapsed fuel line, or like 96capricemgr said something with electrical components are messing up. Ive got the Painless wiring kit setup, so i shouldnt have any problems. But another thing guys is my fuel pump is always on for some reason. I can switch the ignition switch on and hear the fuel pump come on and then go off, but when I actually start the car the fuel pump stays on constantly.

TomTom4049

I suspect you may have the fuel supply and return lines crossed up at the tank.

That is a bit tough to verify but can be done. I'll consult my Haynes manual and write back if I find useful info for you.