Fuel pump relay?

Tiny
MARK1029
  • MEMBER
  • 1995 CHEVROLET SILVERADO
1995 silverado starter turns but fuel pump doesn't run. No power to fuel pump relay with key on but can jump the relay to get fuel pump to run. No fuel coming from injectors and noticed only 2 volts at fuses ecm1 and eng1 when key on. All other fuses in fuse block show over 12 volts.
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Friday, October 19th, 2012 AT 1:53 PM

57 Replies

Tiny
HMAC300
  • EXPERT
Youll have to check to see if pcm is sending a signal to relay. Or if shorted wire at relay box.
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Friday, October 19th, 2012 AT 2:26 PM
Tiny
DELONZAHALL
  • MEMBER
I have the same problem iv done everything I can think of. Fuel pump, dist. Dist. Cap, rotor button, ign. Module, fuses fuel pump relay. My problem is when I turn the key on I get nothing going back to the fuel pump at all. I can jump the relay at the 87 and 30 contact points and the fuel pump comes on but even then I have no spark I have 58psi fuel pressure at the fuel rail. Im at a total loss
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Monday, December 31st, 2012 AT 11:26 PM
Tiny
2CARPROS-ARCHIVES
  • MEMBER
  • 1990 CHEVROLET SILVERADO
How can I jump around the fuel pump relay? Need to test fuel pump.
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Tuesday, June 23rd, 2020 AT 5:29 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
The sure-fire way is to pop the cover off the relay and squeeze the movable contact, but GM made that difficult with the design of their relays. Next is to unplug the relay and use a piece of wire or a stretched-out paper clip to jump the two wires in the socket. This is confusing because there's five wires in it instead of the normal four wires. The wires for the pump motor will typically be larger diameter and / or the connector terminals will be larger. Look for two of those. If you find three larger terminals, the third one would typically be so that same relay can be used in some other application. You should only find two corresponding wires in the connector. Connect those two larger wires to send current to the pump motor.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Here is the location and wiring diagrams for the relay. Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.
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+4
Tuesday, June 23rd, 2020 AT 5:29 PM (Merged)
Tiny
BFLIPPO
  • MEMBER
  • 1995 CHEVROLET SILVERADO
  • 254,000 MILES
My truck will start up fine but the motor won't turn off when I turn off tge key so I hsve to pull the fuel relay also I've noticed that the interior dome lights don't come on. And its the battery dies even after unplugging the fuel relay its like the truck won't completely shut off
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Tuesday, June 23rd, 2020 AT 5:29 PM (Merged)
Tiny
JDL
  • EXPERT
A couple of things I can think of, Check for primary voltage at coil with key off, engine running. Shouldn't be any primary voltage with key off, if so, my first thought is the ignition switch.

It could be dieseling, ignites off high cylinder compression, no spark, or a hot spot in the cylinder/s?

I haven't looked at your wiring yet, but, if there is an oil pressure switch wired in parallel with the fuel pump relay. As long as you have oil pressure, the pump can run, even if you unplug the relay.
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Tuesday, June 23rd, 2020 AT 5:29 PM (Merged)
Tiny
JDL
  • EXPERT
Just to add, I'm not sure of engine litre size?
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Tuesday, June 23rd, 2020 AT 5:29 PM (Merged)
Tiny
SULTY81
  • MEMBER
  • 1995 CHEVROLET SILVERADO
Engine Performance problem
1995 Chevy Silverado V8 Four Wheel Drive Automatic

replaced the relay for the fuel pump and the the fuel pump and still no start unless spray starting fluid then dies as soon as your done spraying
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
2CEXPT
  • EXPERT
Do you hear the fuel pump come on? If so check the fuel pressure-pressure within specification-check for injector/s pulses
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
SULTY81
  • MEMBER
No I do not hear the fuel pump regulating
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
2CEXPT
  • EXPERT
Check for power at the gray wire at the pump connector-power there check the ground circuit if okay replace the fuel pump
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
BADASSTRUCKOWNER
  • MEMBER
  • 1994 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 250,000 MILES
Fuel system won't get power pump relay and fuse is good and when I turn the key on my engine light won't come on it won't even flash when I check for codes
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
HMAC300
  • EXPERT
Check for a broken wire it's orange or the fusible link may have burnt up and it requires a new one. These are normally on starter but cold come from alternator.
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
BRUCEHAZEN
  • MEMBER
  • 1994 CHEVROLET SILVERADO
  • 369,000 MILES
5.7. If I test wires from relay back I have power going through so I know there is not a brake in wires to there a new pump and I have changed relay.

There is a new fuel pump new relay I cannot get power to pump I tested the wires from relay to pump for brakes none found.
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
2CEXPT
  • EXPERT
Try this power the fuel pump connector from the battery and see if it will turn on.
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
BADASSTRUCKOWNER
  • MEMBER
Fuses are good and couldn't find burnt wires I got one orange wire that runs to the fuel relay that is always hot. I ran a hot wire to the fuel pump but still couldn't get injectors to spray
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
BRUCEHAZEN
  • MEMBER
I have power to relay (orange wire) no power coming out when cranking or not if I put power to red wire the pump runs. If I put power to gray wire the pump runs. If I put power to green wire the relay works sends power to pump through the gray wire red wire. Still no power and truck still will not start when I do any of this. When cranking over the engine my oil gauge comes up with pressure so I figure the oil switch is okay. Is this true? Also, if I spray fuel in the throttle body truck will run. Thanks for your time helping me with this problem.
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-1
Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
HMAC300
  • EXPERT
I fyou have power on orange wire then it's the relay if not sending power to pump also when running it runs off of oil pressure switch. Scan for codes because it may be an ignition problem as tbi works only if getting a signal from ignition have module checked at auto part.
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
2CEXPT
  • EXPERT
The computer might not be grounding the fuel pump relay coil side-also test the OPSU.
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-2
Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)
Tiny
BADASSTRUCKOWNER
  • MEMBER
I tried scanning for codes but since the truck died my engine light hasn't came on since
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Tuesday, June 23rd, 2020 AT 5:30 PM (Merged)

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