My truck is not starting after hitting a large bump?

1990 CHEVROLET 1500

2,718,111 MILES • 5.7L • V8 • 2WD • AUTOMATIC

HALFLIFE

MEMBER
5 POSTS

i was out at our farm and was driving back to our driveway and i went through some area we were grading and i hit a very large bump that i did not foresee, my truck just conked out right there. i towed it back to the house and i have done a number of tests but i still can't get it started. I recently replaced the cap and rotor, it has a new transmission, the plugs are new, the plug wires are new, and the fuel and oil filters are new. I know it is getting air, and I watched, and it is getting fuel in what looks like the normal amount when i crank it over. i pulled a plug wire and i am getting spark. What else should i do?

Jul 31, 2023 at 6:59 AM

STRAILER

✓Experienced Mechanic
55,249 POSTS

It sounds like the fuel pump went out which is common, can you see if the engine will run on starting fluid? if so see if you can hear the pump run in the tank after you turn the key on without cranking the engine over, if not here is how to change the pump out and I would swap out the fuel pump relay as well, please go over this guide which can help us fix the problem.

https://www.2carpros.com/articles/car-not-running-advanced

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Aug 1, 2023 at 4:18 AM

HALFLIFE

MEMBER
5 POSTS

The fuel pump is functioning, it's spraying fuel out the injectors. Is there a possibility that it is only part way working?
My only other idea is this, is it possible to knock the timing off? I have a timing chain, so I don't think that it broke, and the engine is turning over, so that should confirm that. Is it possible to in some way shift the distributor/cap-and-rotor set up to the wrong timing?

Aug 1, 2023 at 9:13 AM

HALFLIFE

MEMBER
5 POSTS

I also can hear the pump running when I turn the key. I put a tablespoon or so of gas down the TBI to see if it wasn't getting enough pressure, it didn't even sputter. I also pulled the plugs to check and see if they were fouled, they are not.

Aug 1, 2023 at 9:23 AM

STRAILER

✓Experienced Mechanic
55,249 POSTS

How does it sound when cranking over? Can you please shoot a quick video with your phone so I can hear the noise? That way I can tell for sure if the engine is good or not. You can upload it here with your response. If not let's do a compression test, please follow this guide:

https://www.2carpros.com/articles/how-to-test-engine-compression

Please go over this guide and get back to us.

Aug 2, 2023 at 11:40 AM

HALFLIFE

MEMBER
5 POSTS

Okay, so, I had my friend over and we looked at it and were doing some scanning and the compression test, and in the process, we unplugged the injectors. While I was cranking it for the compression test it started to fire up, so we put the plug back and left the injectors unplugged. It then fired up and ran smoothly for around 30 seconds then sputtered out, so it was a case of having so much gas in it that it didn't start. We then plugged them in and it's running great.
Thanks for the help and taking the time to work with me on this.

Aug 2, 2023 at 10:14 PM

STRAILER

✓Experienced Mechanic
55,249 POSTS

If it does it again you may have a fuel pump or fuel injector going out FYI. Glad you could get it fixed, thanks for letting us know. Please use 2CarPros anytime we are here to help.

Aug 4, 2023 at 3:00 AM

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