No fuel pressure but pump comes on?

2003 CHEVROLET SILVERADO
124,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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HD1200
  • MEMBER
  • 61 POSTS
I repaired some fuel lines and installed a new fuel filter and fuel pump. The truck ran fine before I did repairs. I have no fuel pressure. Nothing coming out of valve on fuel rail. All fuse and relays check good. I can hear the fuel pump coming on for about 3 seconds. I see no leaking fuel lines or pinched lines.

The only thing I think it could be is air in fuel system and lines.

How do I bleed the air out?

Thanks for any help it would appreciateed.
Sep 9, 2023 at 4:27 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,240 POSTS
Hi,

There is no bleed procedure. Air is evacuated from the fuel injectors or returned to the tank.

You may have gotten a faulty fuel pump. You may hear it run, but it does not produce pressure.

When you checked the pressure, was there any at the Schrader valve? Could you have mixed up the fuel lines on the sending unit?

The idea you hear it, leads me to think somehow the return line was mixed up with the supply line. If that isn't the case, the pump is my next suspect.

Let me know. Also, let me know if the original pump that was removed failed or if you replaced it as preventative maintenance.

Take care,

joe
Sep 9, 2023 at 2:15 PM
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HD1200
  • MEMBER
  • 61 POSTS
Update: I found the problem you were right I mixed up connections at fuel rail. I switched the 3/8 and 5/16 and it fired right up.

Thanks for the help.
Sep 10, 2023 at 8:42 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,240 POSTS
Hi,

First, you are very welcome. Believe it or not, that happens more often than you would think. It's not hard to do. LOL

Regardless, I'm glad to know the problem is resolved and it's up and running.

Take care of yourself and feel free to come back any time in the future. You are always welcome here.

Joe
Sep 10, 2023 at 12:35 PM
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HD1200
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  • 61 POSTS
Thanks bud.
Sep 10, 2023 at 11:50 PM
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