1994 XJ Won't Start
07-16-2010, 02:12 AM
#1
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Year: 1994
Model: Cherokee
Engine: 4.0L AMC 242
1994 XJ Won't Start
When I went to go start my 1994 XJ with the 4.0, it would not want to turn over and run. It sounded like it at I was trying to start it with an empty tank, but I had 1/4 left in the tank so I know I had plenty to start.
Once I was able to actually spend time diagnosing the problem, I figured out that I had plenty of fuel at the rail so I knew it was not a pump problem. My battery was fine, so I went on to check for spark. I had no spark. My plug wires/rotor/cap were all brand new but they all checked good. I checked next the camshaft position sensor; it was good too. I moved on to the ignition coil, which I noticed had no spark coming out of it when I directly put on a plug to the wire that normally goes to the cap. I decided to go get a replacement ignition coil, but after putting it in, it did not solve the problem.
After doing some more reading, I find that the Crankshaft Position Sensor is usually the culprit in these kinds of situations. I checked the CPS with my multimeter; I get no reading for resistance but I get 7.31 volts when the ignition is ON and also when cranking; from what I gathered from my FSM, I should be getting some voltage movement when cranking. I went ahead and returned the ignition coil and got a new CPS, but I feel like it could be something else before I have fun with trying to replace the CPS. Anyone else I have any ideas? I would really appreciate it; this is driving me nuts!
Once I was able to actually spend time diagnosing the problem, I figured out that I had plenty of fuel at the rail so I knew it was not a pump problem. My battery was fine, so I went on to check for spark. I had no spark. My plug wires/rotor/cap were all brand new but they all checked good. I checked next the camshaft position sensor; it was good too. I moved on to the ignition coil, which I noticed had no spark coming out of it when I directly put on a plug to the wire that normally goes to the cap. I decided to go get a replacement ignition coil, but after putting it in, it did not solve the problem.
After doing some more reading, I find that the Crankshaft Position Sensor is usually the culprit in these kinds of situations. I checked the CPS with my multimeter; I get no reading for resistance but I get 7.31 volts when the ignition is ON and also when cranking; from what I gathered from my FSM, I should be getting some voltage movement when cranking. I went ahead and returned the ignition coil and got a new CPS, but I feel like it could be something else before I have fun with trying to replace the CPS. Anyone else I have any ideas? I would really appreciate it; this is driving me nuts!
07-16-2010, 07:37 PM
#3
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Year: 1994
Model: Cherokee
Engine: 4.0L AMC 242
I am getting somewhere!
I disconnected the PCM connector and decided to do a continuity check. The B terminal of the CPS connector for some reason was showing connection for some reason to pin 4 and sometimes 5 or 21 which obviously is not pin 24 which is the CPS input. Terminal C for some weird reason is showing up connected to pin 24, but it should be connected to the camshaft position sensor according to the FSM.
It sounds like wires got reversed???
I disconnected the PCM connector and decided to do a continuity check. The B terminal of the CPS connector for some reason was showing connection for some reason to pin 4 and sometimes 5 or 21 which obviously is not pin 24 which is the CPS input. Terminal C for some weird reason is showing up connected to pin 24, but it should be connected to the camshaft position sensor according to the FSM.
It sounds like wires got reversed???
07-16-2010, 10:30 PM
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Year: 2001
Model: Cherokee
Engine: 4 liter
Wires do not reverse themselves.
If your vehicle was running before this latest issue ,replace the crankshaft position sensor. I would strongly recommend against messing with the wiring to the P.C.M.. If you cannot resist the temptation keep detailed notes so you can go backwards if need be.
07-16-2010, 11:52 PM
#5
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Year: 1994
Model: Cherokee
Engine: 4.0L AMC 242
Well, I am pretty sure now that my issue is with the PCM wiring as now I get a code 54 from reading the codes off the CEL.
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