Engine won't crank over?

112,000 MILES • V8 • 4WD • AUTOMATIC
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SWEENWJ
  • MEMBER
  • 1 POST
I couldn't start my Jeep this morning. The symptoms were a dead battery. I attempted to jump it. However, it would act like it started and would die immediately. I let it sit for a while but still the same thing. It starts then dies.
Oct 22, 2010 at 4:48 AM
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SQM
  • ✓Experienced Mechanic
  • 6,383 POSTS
Hello,

It sounds like you might have a faulty crankshaft position sensor. When you have a faulty crank sensor the engine will not produce spark to the plugs.

Due to engine vibration, heat and the constant generation of electromagnetic energy being produced internal windings can become brittle and break causing a direct or intermittent short circuit of the sensor which will cause the engine to stall.
This failure may or may not cause the check engine light to come on and set a trouble code for this problem.
Here are some helpful articles on crank sensor:

https://www.2carpros.com/articles/car-cranks-but-wont-start
https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor
https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

Another possibility is the coolant temperature sensor. Sometimes the temperature sensor can give incorrect signal and the engine will not start.

I have attached the diagrams for your reference.

Please let me know of any questions.

Thank you.
Aug 2, 2021 at 3:29 PM
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