Starting problem

1999 GMC C1500
150,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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KEVIN DALY
  • MEMBER
  • 1 POST
After I have driven the vehicle at high speeds of 75 to 80MPH I will turn the truck off and when I come back to start the truck a couple of hours later it will be hard to start and then when it does start it makes a terrible noise. The noise does stop. If drive the truck at normal speeds this does not happen.
Oct 16, 2021 at 5:37 AM
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SQM
  • ✓Experienced Mechanic
  • 6,383 POSTS
Hello,

When you issue with the hard start, does it crank freely or slow to crank?

Can you please upload a video, so we can hear the noise?

https://www.2carpros.com/articles/engine-noises

Does the truck run hotter than usual?

Let me know.
Thank you.
Oct 16, 2021 at 7:45 AM
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KASEKENNY
  • ✓Experienced Mechanic
  • 18,907 POSTS
Just to jump in with a thought, a video will help but we also need to check the fuel pressure when this is happening as it may not be related to the speed.

This may be a coincidence because the vehicle does not care how fast it is being driven so if it goes to overdrive while driving 50 MPH or 75 MPH it doesn't really know the difference.

Here are a couple more guides that will help with this issue:

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

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

Have you been able to verify test this speed related issue? Meaning have you driven the exact same route going 75 and then going a speed that this does not happen and confirmed the speed is the only variable?

Let us know and either SQM or myself will get back to you.

Thanks
Oct 17, 2021 at 9:30 AM
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