Will not start?

2007 JEEP GRAND CHEROKEE

168,000 MILES • 6 CYL • 4WD • AUTOMATIC

LESLEYB

MEMBER
13 POSTS

My husband is in the delivery business. After numerous starts and stops the vehicle won't start back up it cranks but won't turn over after letting sit for a while sometimes as little as 5 minutes sometimes as much as a half hour it will start back up. then it's fine until the next time. It used to happen not often then happens more often, what could be the problem any advice is helpful. thank you.

Apr 3, 2023 at 7:58 AM

JACOBANDNICKOLAS

✓Experienced Mechanic
110,240 POSTS

Hi,

What you described sounds like a failing crankshaft position sensor. When they begin to fail, oftentimes, they are adversely affected by heat. So, when he shuts the engine, the temp under the hood increases. Once it has a chance to cool, it starts working again.

This is a theory at this point, but it is my first suspect. Take a look through this link and let me know if anything mirrors what you experience:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

If you are comfortable doing it, see if the ignition spark is present at the spark plugs when it won't start. If I am correct, there won't be any spark.

Here is a link that explains how that is done:

https://www.2carpros.com/articles/how-to-check-for-ignition-spark

Let me know what you find, if you have questions, or what I can do to help.

Take care,

Joe

Apr 3, 2023 at 10:32 AM

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