my 92 cherokee 4.0 started stumbling and wont move under its own power. i checked the fuel pressure and it take three key primes to reach a maximum of 10 psi so obviously thats way low. my question is. is that pretty definitive on a bad fuel pump? or could it be something else in the fuel system? the pump sounds normal to the ear.also what pressure it does get it does not hold at all. it starts dropping right away. i guess there is a check valve that will also need replaced?

thanks

 

90 has a filter on the "frame rail" on the left near the tank. I think yours still does, worth checking. Don't hear of the regulator failing often. So pump, maybe filter. The check valve is in the pump, while it's running that shouldn't affect the pressure.

 

I would check fuel filter back drivers side, fuel regulator on injector rail,then pump.I just replaced my fuel pump it would run with 10 psi,but would stumble if you were slightly aggressive with gas pedal.

 

i did check the filter it flows well so its not clogged. im pretty sure its a bad pump since the filter isint clogged and when the regulators go out the pressure is usually to high.
the fuel pump harness and wiring looks good no corrosion. could anything in the ecm cause the pump to not have adequate pressure?

 

The PCM only turns it on or off, pretty sure there. You have a ceramic resistor on the inner fender by your air cleaner. It's just there to knock off a couple of volts because people complained about pump noise. You can check it's connections, just bypassing it is fine. Power from the rear is to the pump, I think it should be at least 9v. Think I have 10 something.