Engine shuts off after 25 minutes?

Tiny
QFONG
  • MEMBER
  • 1995 MERCURY MYSTIQUE
  • 2.5L
  • V6
  • 2WD
  • AUTOMATIC
  • 131,000 MILES
After the engine idles for about 25 minutes, it shuts off and will not restart. The PCM/ECM is very hot to the touch. I can smell unburned gas when I try to restart.
Monday, April 3rd, 2023 AT 11:58 AM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,643 POSTS
The PCM should not be hot, it sounds like you have a shorts injector, ignition coil or a bad ground to the PCM, can you see if the coil is hot as well, if so, I would replace it with a new one. Check out the images (below). Please let us know what happens.
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Monday, April 3rd, 2023 AT 3:41 PM
Tiny
QFONG
  • MEMBER
  • 92 POSTS
The PCM should be grounded from terminals 20 and 60, is that correct? The coil pack is new. It was warm but it sits right over the bank 1 exhaust manifold. I will investigate tomorrow.
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Monday, April 3rd, 2023 AT 5:36 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,643 POSTS
Here are the PCM wiring diagrams so you can see which wires are power and which are grounds.

This guide can help you check:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Check out the images (below). Please let us know what happens.

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Tuesday, April 4th, 2023 AT 10:06 AM

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