92 XJ would not fire in the morning but fired in the heat of the afternoon
#1
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Join Date: Jul 2013
Location: The Dez
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Year: 1992
Model: Cherokee
Engine: 4.0
92 XJ would not fire in the morning but fired in the heat of the afternoon
I have been giving my 92' a little much needed love the last few days. V Cover Gasket, Thermostat / water neck gasket etc... I drove home yesterday from work, parked in driveway which has pretty decent incline, grill facing up, got in this morning and it would crank but no fire. I got home this afternoon during the heat of the day and she fired right up. I live in the desert and it was a cool morning 90's and about 115 when I got home. Any ideas?
#2
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Join Date: Nov 2010
Location: In the middle of Minnesota!
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Year: 1999
Model: Cherokee
Engine: 4.0
You need to determine what part of the starting equation you are missing. Spark or fuel. As it has started since the first symptom, you can assume your compression is okay.
When it doesn't start, take a plug out. Keep it attached to the plug wire, place the plug electrode near a good engine ground, have a buddy crank the engine while you watch. You are looking for a strong, BLUE, snapping spark. Yellow/orange/white indicates a weak spark, which may not be strong enough to start the engine.
If spark is good (and ONLY if), then introduce a small amount of gas into the intake and see if it fires. If it does, you know you have a fuel delivery issue.
The above simple techniques go a long ways on isolating what your problem is. Good luck and keep us updated!
When it doesn't start, take a plug out. Keep it attached to the plug wire, place the plug electrode near a good engine ground, have a buddy crank the engine while you watch. You are looking for a strong, BLUE, snapping spark. Yellow/orange/white indicates a weak spark, which may not be strong enough to start the engine.
If spark is good (and ONLY if), then introduce a small amount of gas into the intake and see if it fires. If it does, you know you have a fuel delivery issue.
The above simple techniques go a long ways on isolating what your problem is. Good luck and keep us updated!
#3
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Year: 1992
Model: Cherokee
Engine: 4.0
Thank you!!
I started with the basics and checked the cap rotor wires.....Keep in mind i am not a total noob ,but I do like to get some ideas before i head into any project. and I did just acquire this Cherokee. The coil wire was so corroded to the cap it broke ... So new all of the above and it runs like a champ. Now just to fix the AC as the blower fuse keeps blowing. I know what is causing it ... just need to fix it! Thanks again!!!!
I started with the basics and checked the cap rotor wires.....Keep in mind i am not a total noob ,but I do like to get some ideas before i head into any project. and I did just acquire this Cherokee. The coil wire was so corroded to the cap it broke ... So new all of the above and it runs like a champ. Now just to fix the AC as the blower fuse keeps blowing. I know what is causing it ... just need to fix it! Thanks again!!!!
#4
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Year: 1999
Model: Cherokee
Engine: 4.0
I don't think I was that much help as you found the problem. But glad it is resolved.
The importance of basic tuneup parts cannot be overstated. Why not finish your tuneup with a set of new Champion copper plugs gapped to .035 and a new fuel filter? All inexpensive and easy to replace.
Enjoy your '92!
The importance of basic tuneup parts cannot be overstated. Why not finish your tuneup with a set of new Champion copper plugs gapped to .035 and a new fuel filter? All inexpensive and easy to replace.
Enjoy your '92!
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