I have a 2002 Jeep Grand Cherokee Laredo, 4.0 in-line 6. I have not been able to get fuel to the engine. I have changed the fuel pump and the crank position sensor. Found out that there is no power to the fuel pump. I did some research and found that the ecm does often go bad on these models. Ordered a new ecm, got it in today and installed it. Still no power to the pump. What am I missing!!! Lost and needing help!

 

Welcome to the forum. I have good news for you! I can tell you exactly what you are missing!

Troubleshooting.

Stop throwing parts at it. Start testing.

Have you checked the fuel pump fuse? Fuel pump relay? ASD relay?

Do you own a multi-meter? A test light?

 

×2

 

I have checked, and double checked all fuses and relays. I got an old ecm from a 98 jeep from a friend, engine won't run with it. I hooked it up to be curious and the fuel pump works and I have full pressure, just doesn't start. Put the new and original ecm back in and the fuel pump doesn't work. Is there anything I'm missing?

 

How did you check the relays? The fuel pump has its own. You need power to the number 30 terminal. You also need power to the number 85 or 86 terminal when the key is on. Then you need to check that there is no break in the wire between there and fuel pump plug. Bear in mind it only goes on for 2 sec when the key is turned on.

 

I do have power to all fuses and relays. With an old ecm from a 98 Jeep the pump does work. Just doesn’t run, that was the issue with the 98 ecm (running issues). I believe ecm issue?! Sending back new ecm for a replacement, crossing my fingers.