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No power to the fuel pump

Tiny
CHEVYFAB
  • MEMBER
  • 1997 CHEVROLET SILVERADO
  • 274,000 MILES
Replaced fuel pump and fuel pump relay; check all the fuses, checked grounds, and still not getting power to fuel pump. Even on relay still not getting power for prime from prong 85 on the relay but when I add direct power to the pump from 87 to 30 the pump powers and sends fuel, I can hear it upper the hood but still nothing when fuse in in truck with key on.
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Sunday, November 28th, 2021 AT 6:14 PM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

I attached a pic below showing the relay and fuse for the pump. Can you tell me which wire you are not getting power to? Is the ECM B fuse in the under-hood fuse box good and does it have power to and from it?

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Let me know. Also, take a look at the attached pic and let me know what is happening there. Also, let me know if you checked for continuity to ground at the relay box.

Take care and I'll watch for your reply.

Joe

See pic below.
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Sunday, November 28th, 2021 AT 10:14 PM
Tiny
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It the bottom right wire dark green with white strip prong 85 on the fuel relay switch that not getting power. I changed the ECM B fuse and still not getting power unless I put direct power from prong 30 on the relay switch to 87 and it power the fuel pump that when I hear the fuel under the hood.
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Monday, November 29th, 2021 AT 11:46 AM
Tiny
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Hi,

I attached the rest of the schematic. That wire comes from the VCM. Go to the VCM, disconnect the connector and inspect the pins for damage or corrosion. Also, if you don't see any problems, check for power at that pin right at the VCM. If it has power, then the green/white wire is open (broken) at some point.

Also, check the ECM1 fuse in the under-hood fuse box. Without power to the green/white wire, the relay won't actuate.

Let me know what you find,

Joe

See pics below. Also, pic 3 shows the ECM1 fuse location in the under-hood fuse box.
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Monday, November 29th, 2021 AT 5:13 PM
Tiny
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After looking and testing and following the wire back to the ECM there no problem whatsoever with the wire or the connector to the ECM. So far, the truck only firing off when I spray starting fluid but still not starting, I check all my grounds and tested they are good. Still not understanding what going on.
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Saturday, December 4th, 2021 AT 3:30 PM
Tiny
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Are the fuses I mentioned good?

Joe
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Saturday, December 4th, 2021 AT 7:39 PM
Tiny
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Yes all of them.
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Saturday, December 4th, 2021 AT 7:53 PM
Tiny
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If you disconnect the connector at the VCM, can you check for power at the pin to the dark green/white wire? If there is nothing from the VCM, we may have an internal problem at that point.

Let me know.

Joe
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Saturday, December 4th, 2021 AT 9:24 PM
Tiny
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I did check but what would be the best way to check that one so I know for sure?
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Saturday, December 4th, 2021 AT 9:26 PM
Tiny
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If there is no power at the VCM, it's most likely bad. There really is no specific test at this point other than taking it apart and inspecting the circuit boards.

Joe
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Saturday, December 4th, 2021 AT 9:28 PM
Tiny
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Okay, I will do this next and get back to you. Do you know a place to get a new one if I have to replace it?
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Saturday, December 4th, 2021 AT 9:42 PM
Tiny
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Hi,

There are online places that provide plug-and-play units. I've used them in the past and had a lot of success.

Let me know what you find. Also, if you determine it if it bad, write down the part number. There should be a label on it or take a pic of it and send it to me. I'll try to narrow things down for you.

Take a look at this link. It's remanufactured/plug and play. Therefore, you won't need to program it.

https://www.fs1inc.com/16229684-1997-chevrolet-c-k-series-1500-5-7l-engine-computer-pcm-ecm-ecu-programmed-plug-play-16213195.html

I believe your module's OEM part number is 16229684, but I would recommend confirming that. There should be a label on it.

Let me know what I can do to help.

Take care,

Joe
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Saturday, December 4th, 2021 AT 10:12 PM

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