Fuel pump relay?

Tiny
GLENN37
  • MEMBER
  • 1989 CHEVROLET SILVERADO
Engine Mechanical problem
1989 Chevy Silverado V8 Two Wheel Drive Automatic 122, oo miles

I replaced the fuel pump relay then the oil sending unit the two wire one. The fuel pump has two quick sounds still will not crank after tring for a while it will crank but will not run long sounds good while running thanks
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Friday, September 5th, 2008 AT 3:06 PM

34 Replies

Tiny
2CEXPT
  • MEMBER
Test the coolant temperature sensor if okay check the fuel pressure to rule out a failing fuel pump or a pressure regulator not maintaining the fuel pressure.
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Friday, September 5th, 2008 AT 3:41 PM
Tiny
WPRIMM
  • MEMBER
  • 1989 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
I thought my fuel pump was bad when I tried to start it and it would just crank, and no fuel was getting to the injectors. So I changed the pump and filter and still no fuel is getting to the injectors, and I cant hear any noise from the pump. Also I noticed that the fuel guage was working with the old "broken" pump but now reads empty with the new one (has about 3/4 a tank of gas in it) dont know if its the fuel relay or an electrical problem, I checked all the inside fuses but their fine.
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Tuesday, July 7th, 2020 AT 1:37 PM (Merged)
Tiny
JDL
  • EXPERT
Hello, did you check wiring at the fuel pump relay, orange wire is hot all the time? The gray wire carries voltage for the pump. If you use a jumper between those two terminals, the pump should run, use an inline fuse. Any fuse you check, also check that the fuse circuit is hot.
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Tuesday, July 7th, 2020 AT 1:37 PM (Merged)
Tiny
REDNECK447
  • MEMBER
Make sure power is going to your engine
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Tuesday, July 7th, 2020 AT 1:38 PM (Merged)
Tiny
EAGLE_ONE_20
  • MEMBER
  • 1989 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
Truck is not getting power to fuel pump I have power to the red wire in middle of conector and power to purple wire that goes in the tank to the float or gas gage but no power to fuel pump. It has good ground I even ran two ground wires of the ground to see if that helped it did not. I have put a new fuel pump relay fuel filter and a tps. Still nothing im lost please help
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Tuesday, July 7th, 2020 AT 1:38 PM (Merged)
Tiny
2CEXPT
  • MEMBER
The fuel pump will only power up for 2 secs due to the fuel pump relay de-energizing. The computer energizes the relay thru its fuel pump control

Have you tried direct power to the fuel pump? If it comes on when direct power is use and the relay has been replaced. Test the wirng-wiring okay, Test computer fuel pump control and fuel pump and oil pressure sending unit.
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Tuesday, July 7th, 2020 AT 1:38 PM (Merged)
Tiny
PLUMBED1
  • MEMBER
  • 1987 CHEVROLET SILVERADO
  • 142,000 MILES
I am attempting to trace why I am only getting 8.4 volts to my dual tank switch on my 87 R30. I have ohmed all the fuses, checked every ground I can find, have jumpered 12 volts directly through the switch, switch connection, and both relay's and got 12 volt's to the fuel pumps, which work fine. I am currently trying to locate a fuseable link that I read about behind the gauges. Have yet to find this mystic wire. Any suggestions?
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Tuesday, July 7th, 2020 AT 1:38 PM (Merged)
Tiny
HMAC300
  • EXPERT
Most fusible links on that year are attached to the starter under the manifold. If you rlinks were bad it could cause this but it almost sounds like a wire is grounding out partially. The pink wire leads to the fuse box off of the ign switch. See diagrams
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Tuesday, July 7th, 2020 AT 1:38 PM (Merged)
Tiny
PLUMBED1
  • MEMBER
Thank-you for the response. If I find the problem based on your advice I assure you that I will make a donation to this web site. You are the only one out of ten responses from other sites that have made any sense. I will be sure to let you know the results.

Dan
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Tuesday, July 7th, 2020 AT 1:38 PM (Merged)
Tiny
LOBOONE
  • MEMBER
  • CHEVROLET SILVERADO
I changed my fuel pump a year ago and it went bad again about a month ago. I have since had intermittent problems with it. Now it won't work at all. I have checked my relay and it is getting voltage. My fuel gauge jumps all the way to the right and then back to the left when I turn the key on. It then settles down. When I installed the new pump it had different colored wires than the other one and I think I have it wired right but is it possible that I have connected a ground incorrectly? Thank you very much.
This is a 1998 Chevrolet silverado 5.0 L 2wd
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Tuesday, July 7th, 2020 AT 1:38 PM (Merged)
Tiny
2CEXPT
  • MEMBER
The fuel pump gets its power from the gray wire the black is ground.

The fuel pump relay only works for 2 secs. and its energize by the computer

below is the fuel circuitry


https://www.2carpros.com/forum/automotive_pictures/12900_pump_wiring_1.jpg




https://www.2carpros.com/forum/automotive_pictures/12900_oil_sending_unit_and_fuel_pump_circuit_19.gif



www.eautorepair.net
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Tuesday, July 7th, 2020 AT 1:38 PM (Merged)
Tiny
MRVASQUEZ
  • MEMBER
  • 1987 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 145,000 MILES
I need help. Fuel pump not working, replaced filter, fuel pump, relay and still will not pump. Can some one help?
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Tuesday, July 7th, 2020 AT 1:42 PM (Merged)
Tiny
BLUELIGHTNIN6
  • EXPERT
Check fuse for fuel pump circuit, is voltage getting to the relay?
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Tuesday, July 7th, 2020 AT 1:42 PM (Merged)
Tiny
MRVASQUEZ
  • MEMBER
Fuse was burnt and replaced but no power. Does the switching valve have anything to do with the pump getting voltage? Tank switch RH LH was burnt as well. Could the ECM gone bad? Wired the pump directly to the battery and pump worked truck turned on. What else can I trouble shoot.

1. Could it be the ECM.
2. Voltage at switch valve fluctuates between 2 an 8 volts.

HELP? TRUCK is CLassic
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Tuesday, July 7th, 2020 AT 1:42 PM (Merged)
Tiny
BLUELIGHTNIN6
  • EXPERT
Must be getting too much voltage on system then to have popped the fuse and the switch. Yes it could be caused by a failing ECM. May also be the oil pressure switch, the fuel pump circuit runs through the oil switch as safety measures. Does the oil pressure gauge work?
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Tuesday, July 7th, 2020 AT 1:42 PM (Merged)
Tiny
WOLFE1
  • MEMBER
  • 1987 CHEVROLET SILVERADO
Electrical problem
1987 Chevy Silverado V8 Two Wheel Drive Automatic

the fuel pump relay has been changed and the switchvalve under has been changed could it be the switch in the cab. I got it started and it run for about 10 minutes then cut off and wouldn, t start backup.
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Tuesday, July 7th, 2020 AT 1:42 PM (Merged)
Tiny
WRENCHER1
  • MEMBER
Have you run battery power and ground directly to the fuel pump to determine if the pump is good?
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Tuesday, July 7th, 2020 AT 1:42 PM (Merged)
Tiny
WOLFE1
  • MEMBER
The pumps are good 0ne is new, when it ran ran for 10 minutes it ran at a high idle but both pumps worked and then cut off and wouldn, t start back up, like no power was getting to the pumps.
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Tuesday, July 7th, 2020 AT 1:42 PM (Merged)
Tiny
WRENCHER1
  • MEMBER
I'll ask you again. Since your problem re-occurred, have you tested the pump by powering it manually?

If not, you need to do that before going any further. Also see if it will run when you do that.
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Tuesday, July 7th, 2020 AT 1:42 PM (Merged)
Tiny
WOLFE1
  • MEMBER
I haveen, t are you saying run a wire from the battery to the fuel pump connector.
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Tuesday, July 7th, 2020 AT 1:42 PM (Merged)

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