Fuel pressure problems.

NEWERA972

MEMBER
1986 CHEVROLET MONTE CARLO
60,000 MILES

I had an engine from a 98'Suburban put in & in my ignorance I had the engine switched from efi to carbureted instead of the car switched to efi. It ran fine for about 1 month & then one day while driving, I couldn't get passed 60mph without the car starving itself for fuel. The next week, I couldn't get passed 50. Then 40, 30 & so on until it wouldn't even idle in my driveway. I was told by a mechanic to have a fuel pump installed by the tank instead of the one by the engine so I had that done and the same course of events followed. Couldn't get passed 60, then 50, etc. The fuel pump pings loudly as if there is no fuel getting to it. I've been told I need a fuel pressure regulator installed. Would this fix my fuel problem? I would like to find the solution before I sink anymore money into the car. Any info would be much appreciated.

1 Reply

HMAC300

MECHANIC
48,601 POSTS

Efi fuel pumps typically average 55-60 psi in your model. A carbureted car needs only 7 psi MAX. I'm sure you will have to do float adjustments as it has been t pushed way to far just to start out. You could try a pressure regulator but also if you went to acrab it only takes one line not two so the return line is more than likely blocked off and needs to be rehooked up. That may be your pinging problem. You might also check your intake vacuum if it is 15" or below check for a plugged exaust. Of cours if the engine has had high performance camput in it depends on the grind that was installed.