1989 Jeep Cherokee Won't Start

Engine Performance problem
1989 Jeep Cherokee 6 cyl Four Wheel Drive Automatic 525K miles

The engine cranks but will not start. This used to be an intermittant problem, some times it would start and other times it would not and sometimes times it would stall and come back while still driving down the road. I have been chasing this gremlin for a long time and have replaced numerous parts with no success. I figure I will have to start over again from the begining using Chilton's and Haynes for refernce. I would appreciate any advice you can give if you see an obvious solution.
Do you
have the same problem?
Friday, September 17th, 2010 AT 10:46 AM

1 Reply

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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Friday, September 17th, 2010 AT 10:56 AM

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