Will not start

Tiny
RANDI URQUIZU
  • MEMBER
  • 2004 LINCOLN NAVIGATOR
  • V8
  • 4WD
  • AUTOMATIC
  • 190,000 MILES
When I go to start my SUV everything lights up when I turn the key but wont crank over. But when I open the hood and tap the A/C compressor with a metal pole and some one turns the key at the same time it starts right up?What could be causing this problem?
Monday, May 20th, 2019 AT 7:33 PM

9 Replies

Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
The compressor can cause a cranks no start issue. It can cause noise in the electrical system that can disrupt the crank sensor signal which the power train control module requires to operate the ignition system.
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Monday, May 20th, 2019 AT 8:22 PM
Tiny
RANDI URQUIZU
  • MEMBER
  • 3 POSTS
So should I replace the whole A/C compressor or what do you recommend? Because it makes a rattling sound as you press on the gas and subsides when you release your foot from the gas.
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Tuesday, May 21st, 2019 AT 5:56 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,321 POSTS
If I can step in here is sounds to me the starter motor has gone bad and the vibration of the tapping helps the starter work. Here is a guide to confirm the issue with a guide to walk you through the starter replacement with diagrams and instructions to help you with the job on your car:

https://www.2carpros.com/articles/starter-not-working-repair

and

https://www.2carpros.com/articles/how-to-replace-a-starter-motor

Check out the diagrams (below). Please let us know what happens.
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Thursday, May 23rd, 2019 AT 2:06 PM
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
Absolutely correct Ken! Don’t know why I didn’t think of that.
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Friday, June 28th, 2019 AT 8:31 PM
Tiny
RANDI URQUIZU
  • MEMBER
  • 3 POSTS
Turns out it was the A/C compressor clutch that was causing the problem.
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Sunday, June 30th, 2019 AT 11:04 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,321 POSTS
How can that be? Was the compressor locked up?
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Monday, July 1st, 2019 AT 11:17 AM
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
Awesome! We’ve actually run into this at my dealership Ken, the clutch can induce noise into the electrical system and disrupt the crank signal since it is only a 0-1 volt signal. This is why hall effect sensors were later used on newer models. I’m glad you got it fixed my friend!
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Wednesday, July 3rd, 2019 AT 8:57 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,321 POSTS
O man! I love it, learn something new everyday :) Great info.
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Wednesday, July 3rd, 2019 AT 1:06 PM
Tiny
PATENTED_REPAIR_PRO
  • MECHANIC
  • 1,853 POSTS
I assume this was a crank and no start instead of a no crank, which just means the starter isn't cranking over the engine.
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Thursday, July 4th, 2019 AT 2:57 AM

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