I have a 2000 Jeep Grand Cherokee. It had been running fine. My daughter parked it, and about 6 hours later went to start it, it cranked but wouldn't start. I read a little about the cps, so tried unplugging that, but no joy. I verified fuel pressure at the rail, which rebuilds if I bleed it off. I took off the spark bar, and checked the first wire attachment for spark, but nothing. The gas gauge doesn't move, the fuel empty lamp is lit, and when I turn the key on, the rad fan starts going. The odometer does show the mileage. At one point, the battery terminal was a little loose, as I had taken it on and off a few times, when I turned the key at that point, I got a clicking, and the gas gauge started reading. After i tightened the battery cable though, the gas gauge stopped working again with key on. Also,when the key was off, i took the battery cable off then put it back on again, and the rad fan started running for a few seconds. Is that normal? I'm thinking I should check all my ground wires, but I'm thinking I might have a bad ecm. Any ideas of what I should check next?

 

Check for codes ...

 

When you checked the fuel pressure did you check it with a mechanical presser gauge? That is the only way to know if you have the right pressure to run the engine. I don't know about the GC But the XJ's with the 4.0 need at least 49psi (+ or - 5psi). You might get a little more help if you post the engine size and post this in the GC section. Also like freegdr said you need to check it for any codes. The code check sould be the first thing you need to check. One other thing normally when the CPS goes bad you will lose both spark and fuel.

 

This is a 4.0 engine. I put the scanner on with the key on, but my scanner just says no link. i didn't test fuel pressure with a gauge, i just bled off from the rail, but it did seem to keep rebuilding pressure once bled off. On the cps, I measured resistance between ground and the 5volt power line while unhooked, and it showed about 5 ohms. I tried to get voltage with the key on, connector in place, between the 5volt power line and the ground, and it only showed 45 milivolts. I'm referring to the wire on the right with the connection clip on top as you face into the connector from the cps as the 5volt power line.