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will not run

S

steve31086

NAXJA Forum User
Location
Milford, CT
my 88 xj will not run. so far we have replaced the whole wiring harness(done professionally), fuel pump, computer, distibutor, cap, rotor, wires, plugs, ballast resistor, battery. it will turn and then just shut off when i bring the key to the run position. oh and also...it will run off of ether...i dont know if that helps?
 
i assume you read the search threads i sent you? its just a matter of troubleshooting 1 step at a time... oh yeah.. welcome to NAXJA!!!!
 
If you dont mind me asking, about how much did it run to replace the wiring harness? Where did you get the new harness? How much did it cost alone?

Brian
 
If will run off of eather but not on its own you have a fuel problem. either the fuel pump is not working or you have a bad fuel filter or you injectors are not working. First thing I would check is the fuel pump check to see if you can hear it come on when the key is turned to the run position it will only come on for a short time. If you dont hear it try swapping the fuel pump relay (under the hood) for the A/C realy and see if it starts. If thats not the problem you will need to troubleshoot further. Good luck
 
BigDadys94xj said:
If will run off of eather but not on its own you have a fuel problem. either the fuel pump is not working or you have a bad fuel filter or you injectors are not working. First thing I would check is the fuel pump check to see if you can hear it come on when the key is turned to the run position it will only come on for a short time. If you dont hear it try swapping the fuel pump relay (under the hood) for the A/C realy and see if it starts. If thats not the problem you will need to troubleshoot further. Good luck
Click to expand...

I suggest also that you or your mechanic get a "noid light" or injector tester and make a preliminary check to see if the injectors are firing. This will let you know right off the top whether you should be looking for an electronic problem there, or at a fuel delivery problem.
 
I'm confused. You say it starts, but when you turn the key to run it dies. That is a symptom of a bad fuel pump ballast resistor. I know you said that you changed it, but measure the voltage on the fuel pump when the key is in the run position. If the pump is indeed running it should be around 7-9 volts. If you just jump in and turn the key to on, do you hear the fuel pump run for a few seconds. If not, it is most likely the resistor. I have seen pumps that would not work on the lower voltage but they are rare.
 
okay...replaced the relay, still didnt start, tested the fuel pump, thats okay, and just for fun we replaced the CPS. now the noid lights...theyll turn on when the key is in the "start position" but as soon as we put it to "run" they turn off. fuel injectors is the problem?
 
and oh yeah...brian...the wiring harness cost me nothing(i have a few mechanic friends) and yes we still cant figure this out. but if you want me to ask someone what they would charge i can.
 
steve31086 said:
okay...replaced the relay, still didnt start, tested the fuel pump, thats okay, and just for fun we replaced the CPS. now the noid lights...theyll turn on when the key is in the "start position" but as soon as we put it to "run" they turn off.
Click to expand...

I can't help but notice that "ignition switch" is not in your list of replaced parts. They seem to be fairly common points of failure. I can't say "for sure" that they're capable of causing this condition, but.....

Den
 
steve31086 said:
okay...replaced the relay, still didnt start, tested the fuel pump, thats okay, and just for fun we replaced the CPS. now the noid lights...theyll turn on when the key is in the "start position" but as soon as we put it to "run" they turn off. fuel injectors is the problem?
Click to expand...

Another idea here. You say that it is turning over correct? But it will not fire up, right? As a guess, or another thing to check, I would suggest the Timing Chain. My father and I went thourgh the same crap with a Dakota. Replaced all kinds of parts (electrical), checked fuel injectors, etc...., long story short timing chain was the problem. Hope this helps........
 
I'm going to have to second the ignition switch. Should be easy enough to check with a volt meter to see if all the proper connections are being made and maintained in the proper position.

Just to clarify a little. If you were to hold the key in the start position (although not really good for the starter) would the Jeep keep running just fine??
 
All depends on how the switch is designed. Figure that there might be multiple power feeds off the switch. Most switched work by a copper button following a copper strip. In the run position, the metal button spends most of its time sitting in one spot, vibrating, possibly wearing away the strip or leaving wear deposits. In the start position, the metal button is in a different location, possibly a clean location, but as soon as you let the key return, that contact moves back to the dirtly location and looses connection.

This still doesn't mean its the problem, like you said, but it is possible reasoning for why it could be the problem.
Good luck!
 
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