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2003 cummins no power to fuel pump

86K views 53 replies 16 participants last post by  rghavana 
#1 ·
Okay so while driving home the other day i lost fuel pressure. I get the truck to my dads and realize that my fuel pump was not pumping any fuel, so i pulled the bed off and bought a airdog "figured if i was gonna replace the pump ill do it right" so i installed the airdog and it wouldnt come on. So i got to checking and im not getting any power thru my wiring harness my fuel gauge works but not my fuel pump. I can run a positive and a negative from the battery to the airdog and it comes on. I got the injectors bled off and the batteries died so i walked away before my temper got the best of me so now im back at work and my truck is two hours away at my dads so i need some help please.:banghead::banghead::banghead::banghead:
 
#3 ·
Thank you for the wiring schematic., and temper tantrums really i dont think i was throwing a tempur tantrum. But like i said thank you for the schematic
 
#4 ·
check to make sure your relays and fuses are all hooked up correctly. Along with the fuel pump fuse in the fuse box under the hood.
 
#5 ·
See thats the thing i checked for fuses and relays when i first found out that i wasnt getting any power but their is no fuse or relay for the fuel pump in the fuse box. From what i was told the ecm has a internal relay that is for the fuel pump
 
#13 ·
as I mentioned above, the dealer added intank pump, installs an extra wiring harness, relay is located on drv side near brakebooster, and from there the power for it is taken from the drv side battery, you should see a fuse holder hooked to the positive terminal
 
#7 ·
Does your air dog have OEM plugs on it like Fass does? Or did you have to cut and splice? Have you also tried bumping the ignition so see if the pump will run at all? There are several fuses under the hood that do affect fuel control. Check them visually not just with a test light.
 
#8 ·
it does but the harness is getting shipped seperatly cause they forgot to include it so i havent even put it on yet and i have checked every single fuse under the hood i took them out one by one and checked them i am trying to find a relay for it maybe its bad idk. ive been without my truck for 2 weeks and im having to drive our "backup" car and its a turd so its killing me lol
 
#9 ·
How are you coming to the conclusion that you have no power to the pump?
 
#10 ·
I turned the key on and the fuel pump would not turn on so I tested all 4 wires " my pump is in the tank not on the back of the filter housing" and was not getting any power to the pump with the key on so I found the hot wire to the pump and ran a wire from the battery and it came on


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#12 ·
you realise that in order to keep the LP running you have to "Bump" the starter?. also if you have an 03 that originally had a LP on the engine block, then they were moved to the tank, you should have an extra relay fastened to the firewall, and a extra wire at the drv side battery, if you have unhooked this the LP will not work. the connector for the Fuel pump is over near the starter, unplug it there then plug your air dog connector to that.after doing that it will disable the dealer added wiring harness for the intank pump
the LP circuit will only be energised for 15-20 seconds after bumping the key. so unless someone is bumping the key and your checking for power, you wont have time to do it all yourself
 
#14 · (Edited)
If your year has it, check the 30 amp PCM relay in the fuse box in the engine bay. Should be swappable with your trailer relay. Atleast it is in my 06. This happened to me the other day on the way home. I swapped them out and I was good as gravy.
 
#15 ·
In behind the plastic wheel well liner on the drivers side front wheel, down low there are 2 wiring harness plugs. One of these sends power to the in tank fuel pump. Unplug the correct harness and check the pins for corrosion. The ground pin may be corroded and not making the connection. As a side note, the in tank pump will not start unless it sees a full 12 volts. That little bit of info could have saved me almost $2000 three years ago. The engineer that thought it was a good idea to put 2 wiring harness plugs behind the front wheel should be beaten with a steaming turd.
 
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#16 ·
yes i do realize the bump the starter but i did not know were all the plugs were so thank you for that and i had the dealer run my vin number and he said when the truck was built that the pump was built into the tank not on the back of theh filter canister.
 
#17 ·
I have noticed the fuse holder on the battery but i did not know what it went to the fuse has a hard time staying in it so i will replace that and go from their thanks so much guys
 
#18 ·
Truck is up and running. The fuel pump relay went bad. I guess when the dealer installed it they forgot were they were supposed to mount it at cause it wasnt mounted it was just hanging down by the frame.... Thanks guys
 
#19 ·
I'm having the exact same issue on my 04.5. driving down the hwy it just sputtered and died like running out of fuel. gauge reads just under 1/2 and theres fuel in the canister but no fuel pressure. I pinned the in tank pump harness with help to bump the starter and got no power, traced it to the wheel well and pinned there at a connector and still no power. pulled a generic code that stated low fuel pump voltage (no really).. checked fuses 1 by 1 and theyre all good, gonna check for that relay ppl are speaking of at the battery in a few. Does anyone have any other ideas or ways to check for issues?? Thanks
 
#21 ·
Im not seeing this link, is it hidden within the wire loom? Ive looked hi and lo and not able to see it. The other day the truck did this and i happened on to a blown fuse called "trailer battery", i replaced it and the truck ran. I went home than back to a friends and it died again with exact symptoms. Checked all fuses and flip flopped some relays but no luck. Im sure im overlooking something but what?????:confused:

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#25 ·
Ok now im at my computer so i will tell you what i did to fix my truck. On the driverside battery their is a wire that is about 10 inches long that goes to a inline fuse. Check the fuse then follow the wire to the relay check your relay with another one from your fuse box. if it is not bad run a hot wire from your battery to the plug on top of the fuel pump an dtap the hot wire. If the pump does not come on then the pump is bad if the pump does come on then you will need to trace the wires from the relay to the pump.
 
#26 ·
I've been having the same Problem. Now with this thread I was able to find out the in tank pump that I just had changed is not turning on. I do have the fuse and relay. The fuse is good I checked power 12.51 volts checked the relay has power going in but none going out. Tried another relay from the brake lights and still nothing. Truck will not start without a quick spray of ether. Any help is greatly appreciated.
 
#27 ·
Check you voltage at the pump with the key on. If your pump is not comming on but you said the truck will start BE CAREFUL i have found that a good injector pump will pull your fuel up even if the lift pump is not and this is the main cause of injection pumps going out.
 
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