Oil pressure gauge reading low

[knucklehead]

98 GMC 5.7 has approx 140k miles... Oil pressure gauge reads almost zero at hot idle. I want to hook up a mechanical gauge to verify oil pressure readings since the gauge is reading low after replacing the sending unit. Will the engine run with no signal from the sending unit? I have read that if the pcm doesn't see oil pressure, then the engine won't run. Thanks everyone!

 

[Schurkey]

98 GMC 5.7 has approx 140k miles... Oil pressure gauge reads almost zero at hot idle. I want to hook up a mechanical gauge to verify oil pressure readings since the gauge is reading low after replacing the sending unit. Will the engine run with no signal from the sending unit? I have read that if the pcm doesn't see oil pressure, then the engine won't run. Thanks everyone!

Yes, engine should run--IF (big IF) the fuel pump relay, the ECM, and all the fuel pump wiring harness is in good condition. There's an oil pressure switch bypass for the fuel pump relay. If there's already a problem in the fuel pump relay system, and you disable the oil pressure switch, the pump may not run.