no start on 94 Grand Cherokee

Old 11-11-02, 06:43 PM
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no start on 94 Grand Cherokee

I am working on a 94 Grand Cherokee with a 5.2 (318) and an auto trans. The vehicle would quit and then not start. The first time I did not have any fuel pressure showing on the fuel gauge hooked up to the rail but I had spark. I changed the fuel pump and it ran for about 3 weeks. When I checked it this time I had fuel pressure (39 psi) at the rail but no spark. I checked the inputs to the coil, I had them, the coil fins were split. I changed the coil and again it ran for about a week. This time no fuel or spark. I hooked up a scan tool and found no rpm input. I followed the diagnostics and changed the crank sensor. It started fine but it quit 2 days later. I haven't looked at it since, kinda disgusted and not sure where to go next. Kinda thought maybe it could be a PCM, but not quite sure. There are no stored codes in the PCM and when it is running it runs fine. Has anyone come across this problem? Any help would be appreciated. Thanks.
Old 11-12-02, 05:18 AM
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I havent come across this in a Jeep before but I have in chevys.
there is most likely a short in the ECM or Prom sys. that is heating the ECM up and shorting out key systems.
I would recommend an ECM swap out.Try a used one from a wreckers if you can find one.
Old 11-12-02, 05:58 AM
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Have the computer sent out to a local parts store's electronics supplier for testing. See what that reveals.

It is cheaper and more effective than buying a PCM only to find out it's not the problem.

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