I have an '85 IROC. When I first start the car, it idles fine, right between 750 and 1000 rpm. As it warms up, and once I drive it, the idle drops down to 400 - 500 rpm, regardless of whether my foot is on the brake, many times it stalls. It has stalled before and needs to sit for about 5 minutes then it will fire right back up again. I checked the code, and I got a code 54, fuel pump low voltage. Any suggestions?

 

I am not sure on the 85's but does anyone know if they have a fuel pump speed controller?.cause your problem might be located at that component if it does have one.I dont know if your car does or not.If it doesnt have one have you tried replacing the pump yet?

 

If this engine has a oil pressure safety switch, would a faulty oil sending unit cause the fuel pump to cut out?

 

Ya ,..sure its possible.But hes getting a code 54.I dont see the sending unit wiring tied in with a code 54.I see ECM-connectors-fuel pump controller-and fuel pump itself... no oil sending unit?.If he wasnt getting a code then I would say ya.. check out that oil sending unit.

 

The "fuel pump controller" is called a relay. The fuel pump is supposed to get full system voltage whenever the relay is closed. Further,the auxilliary oil pressure switch is NOT a safety shut-off for the fuel pump. This is NOT a Ford. GM systems use the oil pressure switch as an alternate, redundant path for fuel pump power. If the relay circuit fails, cranking the engine long enough to produce 7 PSIG oil pressure will provide power to the fuel pump.

 

So in other words ,it sounds like something is overheating..bet the pump is worn out and maybe the relay(fuel pump controller)Do a pump and inspect the wires really good.Possibly replace the connector to the pump,to be a on the safe side.