Intermittent not starting issue

1997 MERCURY MOUNTAINEER
179,000 MILES • 0.5L • V8 • 4WD • AUTOMATIC
Avatar
MIKE TRUEBLOOD
  • MEMBER
  • 2 POSTS
I have replaced the fuel pump fuel filter relay and inertia switch on my vehicle listed above. It will run and start but only when it chooses to. It might run today and not run tomorrow. Any ideas? Thank you in advance.
Jan 26, 2021 at 6:30 AM
Advertisement
Avatar
JACOBANDNICKOLAS
  • Experienced Mechanic
  • 110,240 POSTS
Hi,

When it doesn't start, did you confirm there is no fuel pressure? Also, is the check engine light staying on when the engine is running. Can you hear the pump turn on when it doesn't start and have you checked for ignition spark to the plugs when it doesn't start?

Try this: When it doesn't start, see if it does for a couple of seconds and then stall. If it does, then we know it is a fuel related issue. Or, here is are two links that explain how to check fuel pressure and for ignition spark. You can do that if you feel comfortable doing it.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator


https://www.2carpros.com/articles/how-to-test-an-ignition-system

Let me know.

Joe
Jan 26, 2021 at 6:52 AM
Avatar
MIKE TRUEBLOOD
  • MEMBER
  • 2 POSTS
Thank you Joe. sorry it took so long for a response. I ended up having to change the fuel pump again the one I put on was faulty. But it had a warranty. thank you so much for your response.
Mar 7, 2021 at 2:03 AM
Avatar
JACOBANDNICKOLAS
  • Experienced Mechanic
  • 110,240 POSTS
Hi,

First, you are very welcome. I'm glad you got it running properly again. Always remember, if it doesn't start, first confirm there is proper fuel pressure and you have ignition spark to the plugs. In almost all cases, one or the other will be the issue. At that point, you can focus on that component.

Regardless, please feel free to come back anytime in the future. You are always welcome here. Also, thanks for letting me know. Chances are your post will help others.

Take good care of yourself,

Joe
Mar 7, 2021 at 10:22 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.