No Power at fuel pump relay

Tiny
MDM6713
  • 1997 CHEVROLET EXPRESS

Electrical problem V8 Two Wheel Drive Automatic 155000 miles

1997 Chevy Express 2500 Van 155,000miles, Engine died in parking lot, we installed a new fuel pump, but noticed no power to Grey wire going to pump. Check the relay and it bench tests fine, however, no power is sensed at the proper terminal to turn on the relay. Not even a 2 second pulse when cycling the key of and on. Whats the next step I should take?
thanks a lot
Michael

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Friday, October 24th, 2008 AT 2:34 PM

5 Replies

Tiny
RASMATAZ
  • MEMBER

Hi mdm6713 and welcome to 2carpros

It sounds like you have a power failure such as a bad connection or a trigger failure of such kind, here is the fuel pump wiring which is in the engine wiring (below) so I gave you the entire engine wiring diagram and a guide so you can do some testing.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

and

https://www.2carpros.com/articles/how-to-check-wiring

Please run this test and get back to us so we can keep helping you.

Cheers

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Friday, October 24th, 2008 AT 3:44 PM
Tiny
MDM6713
  • MEMBER

Actually I was wrong, I did have the 2 secs worth of power at the relay. This is what Im expeirencing now, The fuel pump will cut on for the 2 secs time only if the oil pressure switch at the rear of the engine is disconnected. Does it sound faulty? Another thing, I can jump the wires on the oi pressure switch and the pump will operate. However, it will only blow air, no fuel. I re-assemblied this twice already. Can you think of what Im doing wrong? Thanks a lot for your help
Michael

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Friday, October 24th, 2008 AT 6:17 PM
Tiny
RASMATAZ
  • MEMBER

If the fuel pump comes On for 2 secs it should produce pressure -check it with a fuel pressure gauge and report back your readings. When the engine fires up this is where the oil pressure sending unit powers the fuel pump.Also check for injection pulse width with a noid light

Your OPSU is okay if it turns On the pump while jumpered and key at run


http://www.2carpros.com/forum/automotive_pictures/12900_oil_sending_unit_and_fuel_pump_circuit_80.gif

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Friday, October 24th, 2008 AT 6:23 PM
Tiny
MDM6713
  • MEMBER

Ok, I bench tested the pump to make sure I wasn't crazy, pumped fine. What I did was fill up the capsule with fuel while inserting into the tank, (primed it in a way) Well, started right up. I dont know if thats a common problem but I was surprised not to find anything online about priming the pump.
Michael

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Friday, October 24th, 2008 AT 9:08 PM
Tiny
2CARPROS KEN
  • ADMIN
  • 11,072 POSTS

Its sounds more like you had a bad connection at the pump which is a common failure.

Here is an AC Delco pump for 157.00 on Amazon

https://www.amazon.com/gp/product/B00171UG4G/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&tag=2carprcom-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B00171UG4G&linkId=ab2a6bb147556d7f0b2a6c2651f00e52

Please let us know what happens.

Cheers, Ken

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Saturday, September 9th, 2017 AT 7:02 PM

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