No power to fuel pump - Relay?

Tiny
LEGENDWOLF
  • MEMBER
  • 1999 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 42,000 MILES
Started truck to warm up, shut off after about 5 min. Would not start back, no sound of fuel pump priminng. Could not find a fuel pump fuse, but swapped pump relay out with other relay's, still no fuel pump priming. Checked for power to relay with key on and off checked out ok. Suspect bad fuel pump, replaced with new Bosch fuel pump. Still no fuel pump priming. Know suspect electrical problem but don't know where to look.
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Friday, December 12th, 2008 AT 8:27 PM

41 Replies

Tiny
2CEXPT
  • MEMBER
At the fuel pump relay backprobe the dark green and black wire when key at run positon-You should have power -let me know

Check out the diagrams (Below). Please run this test and get back to us.
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Friday, December 12th, 2008 AT 8:54 PM
Tiny
LEGENDWOLF
  • MEMBER
Have power at relay, but not at pump connection
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Saturday, December 13th, 2008 AT 3:49 PM
Tiny
2CEXPT
  • MEMBER
Did you get that power from the dark green and black wire at the relay? This wire powers the pump
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Saturday, December 13th, 2008 AT 4:40 PM
Tiny
LEGENDWOLF
  • MEMBER
Took top off of relay, I can manually close the connection at the relay and fuel pump will run.
I am getting power to relay from key switch, but not sure about signal from PCM.
What would keep PCM from signaling fuel relay?
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Saturday, December 13th, 2008 AT 8:07 PM
Tiny
2CEXPT
  • MEMBER
The computer control of the relay is defective-listen to the relay while helper turn key to run-did it click if not its no good.
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Saturday, December 13th, 2008 AT 9:52 PM
Tiny
LEGENDWOLF
  • MEMBER
Relay does not click when key is turned on, it's a good relay.
Is computer control BAD?
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Sunday, December 14th, 2008 AT 11:31 AM
Tiny
2CEXPT
  • MEMBER
Its gone-unable to energize the fuel pump relay-it has to activate the relay in order for the fuel pump to receive power
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Sunday, December 14th, 2008 AT 11:40 AM
Tiny
LEGENDWOLF
  • MEMBER
Sounds expensive to replace.
Truck will run when I manually signal the fuel pump, Is there any way to confirm computer is bad?
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Sunday, December 14th, 2008 AT 12:20 PM
Tiny
2CEXPT
  • MEMBER
Not really I would get a used unit that is the easiest.
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Sunday, December 14th, 2008 AT 5:05 PM
Tiny
LEGENDWOLF
  • MEMBER
Thanks for your help Rasmataz.
Great site Quick response, plan on donating.
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Sunday, December 14th, 2008 AT 5:57 PM
Tiny
2CEXPT
  • MEMBER
Sir-We try to assist everyone that comes for help expediously cuz there's so many of you. You're always welcome aboard. Good Luck and Merry Christmas and Happy New 2009 and a prosperous one-
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Sunday, December 14th, 2008 AT 8:07 PM
Tiny
DAFATKID88
  • MEMBER
  • 1999 DODGE RAM
  • 5.1L
  • V8
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
Ran over a curb truck was running it cut off and will not start back up.
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Tuesday, August 25th, 2020 AT 5:11 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
Inertia switches are a troublesome Ford thing. What is the exact symptom? Does the starter crank the engine? Is everything out, including the instrument cluster? What is the correct engine size?

The first thing you need to do is read and record the diagnostic fault codes. Chrysler made doing that yourself much easier than any other manufacturer. Cycle the ignition switch from "off" to "run" three times within five seconds without cranking the engine, leave it in "run", then watch the code numbers show up in the odometer display. List any codes in your reply and I will interpret them for you, or you can go here for the definitions:

https://www.2carpros.com/trouble_codes/obd2

You need to check for spark in the normal fashion, and check for fuel pressure. Try to listen for the hum of the fuel pump for one second after turning on the ignition switch. If you have no spark, start by inspecting the connector and wiring for the crankshaft position sensor. It is important to understand that sensor's circuit can have a problem and may not set a fault code just from cranking the engine, so we cannot assume it is okay if there is no code related to it.
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Tuesday, August 25th, 2020 AT 5:11 PM (Merged)
Tiny
USER314
  • MEMBER
  • 1999 DODGE RAM
  • 5.2L
  • V8
  • RWD
  • AUTOMATIC
  • 125,000 MILES
The fuel pump keeps cutting off. We took it out and tested it to a battery and the pump still works. We also also tested the relay listening for the clicks and switching them, but the fuel pump still is not working.
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Tuesday, August 25th, 2020 AT 5:11 PM (Merged)
Tiny
SATURNTECH9
  • MEMBER
So when the fuel pump is not working are you missing the ground side or the power side?
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Tuesday, August 25th, 2020 AT 5:11 PM (Merged)
Tiny
HMAC300
  • EXPERT
Check fuel pressure it may be to low or pump is getting hot and cutting off. gasoline lubes it so that may be why. also try resetting security system if no owners manual look online. auto parts rent gauge. here is an article to help
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
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Tuesday, August 25th, 2020 AT 5:11 PM (Merged)
Tiny
SATURNTECH9
  • MEMBER
With the key in the run position is the security light on solid or flashing?
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Tuesday, August 25th, 2020 AT 5:11 PM (Merged)
Tiny
BRAMLETT1981
  • MEMBER
  • 1998 DODGE RAM
  • 5 CYL
  • 189,000 MILES
I have a dodge ram 98 5.9, I have checked the fuel pump which works great (It is fairly new as it was replaced 3 months ago), I have tested the fuel pump relay and it seems to work right when testing but doesn't work right when actually ON the truck. Anyone have any idea what could cause the relay to work right OHM/volt testing but not work on the truck?

Summery: The truck died at 55 MPH now cranks but will not start, the fuel pump IS working, the Fuel relay works ONLY when OHM tested. Currently there is no gas getting to the engine but I have gas, no power to the fuel pump. I have checked all fuses and they all work.

Any help would be greatly appreciated! Thanks!
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Tuesday, August 25th, 2020 AT 5:11 PM (Merged)
Tiny
2CEXPT
  • MEMBER
Check and test the ASD relay, also the actual fuel pressure with a gauge and check for spark and also if the injectors are pulsing-
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Tuesday, August 25th, 2020 AT 5:11 PM (Merged)
Tiny
BRAMLETT1981
  • MEMBER
Thanks for the quick reply. We did JUST get it figured out and the truck is running, it seems to be a problem with the prongs of the Fuel relay. If you jiggle it, it works. Guess I need to go buy a new one, the prongs are not connecting right. Oddly enough a suggestion from my wife, sure enough her suggestion was correct. Don't tell her that! Lol
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Tuesday, August 25th, 2020 AT 5:11 PM (Merged)

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