Fuel Pump Wiring Diagram (PART 1)
NOTE: The above fuel pump and fuel pump relay wiring diagram applies only to 1993, 1994, 1995 4.0L Jeep Grand Cherokee.
Fuel pump troubleshooting notes:
- The fuel pump relay gets power from fuse #6 (15 Amp) of the Power Distribution Center (PDC).
- Fuse #6 (of the PDC) also feeds power to a few other components (see: Fuel Pump Wiring Diagram -PART 2).
- The PCM activates the fuel pump relay and the auto shut down (ASD) relay at the exact same time and thru' the same circuit (PNK wire).
- The PCM activates the fuel pump relay for 1 to 3 seconds when the ignition switch is turned to the RUN position but the engine is not cranked or started.
- As you're cranking the engine to get it started.... the PCM maintains the fuel pump relay activated only if it receives a crankshaft and camshaft position sensor signal (that shows the engine cranking or running). If either sensor indicates no engine RPMs, the PCM will not activate the fuel pump relay past the 1-3 seconds initial run time.
- The factory fuel pump specifications are:
- Key On Engine Running: 31 PSI (2.2kg/cm²).
- Key On Engine Off: 39-41 PSI (2.7-2.9kg/cm²).
- Key On Engine Running (but no vacuum applied to fuel pressure regulator): 39-41 PSI (2.7-2.9kg/cm²).
You can find the ASD relay wiring diagram here: 1993-1995 Auto Shut Down (ASD) Relay Wiring Diagram (Jeep 4.0L).
Fuel Pump Wiring Diagram (PART 2)
Fuel Pump Relay/Fuses Location
For a complete description of the relays/fuses of the power distribution box, see:
Where To Buy The Fuel Pump
The best place to comparison shop and get an idea of how much your Grand Cherokee's fuel pump and fuel pump relay cost (and how much you can save) is here:
Not sure if the above fuel pump and/or fuel pump relay fits your particular Jeep Grand Cherokee? Don't worry, once you get to the site, they'll make sure it fits by asking you the particulars of your vehicle. If it doesn't fit, they'll find you the right one.
More Jeep 4.0L Test Tutorials
If this tutorial was helpful/informative, you can find a complete list of tutorials here: Jeep 4.0L Index Of Articles.
Here's a sample of the tutorials you'll find there:
- How To Test Trouble Code P0135 (1996-2000 Jeep 4.0L).
- How To Test The MAP Sensor (1997-2003 Jeep 4.0L).
- How To Do A Cylinder Balance Test (Jeep 4.0L).
- Jeep PWM Fan Relay Test Troubleshooting An Overheating Condition.
- How To Test The Crank Sensor (Jeep 4.0L -1997-2004).
If this info saved the day, buy me a beer!