Mechanics

NO FUEL PRESSURE

2003 Dodge Ram

Engine Mechanical problem
2003 Dodge Ram V8 Four Wheel Drive Automatic 147000 miles

I was slowed down to pull into a gas station and my truck died. I have the 5.7 Hemi. It would not start back up, I checked the fuel pressure and had none. I did not get any codes and have a half tank of gas. I bought a new fuel pump and installed it but the truck still has no fuel pressure. I switched out the Fuel pump relay fuse earlier and it had no effect. Not sure where to go from here. Thanks!
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NickDavis04
March 11, 2010.



Usually people mistakenly think there is fuel pressure. Can you hear the pump run for one to two seconds after turning on the ignition switch? If not, listen under the tank when a helper turns on the switch. If it still isn't heard, bypass the fuel pump relay or Automatic Shutdown (ASD) relay. I can walk you through that if necessary.

Caradiodoc

Caradiodoc
Mar 11, 2010.
I checked the voltage to the wires on the fuel pump. I found that there is a blue/white wire that has 11.37 volts. And the green/white wire only has.37 volts. I'm not sure what the blue/white wire is for (fuel sensor maybe). And before checking the voltage I checked to see if I could hear the fuel pump when the key is turned to the on position. I heard nothing. I'm thinking I may need to jump the green/white wire?

Tiny
NickDavis04
Mar 11, 2010.
I ran an cable from the green/white wire to the fuel relay. It started right up! Is there a reason or way to fix the problem now that I know its just not getting power?

Tiny
NickDavis04
Mar 11, 2010.
Check fuse # 17 under the hood. If it is ok, check for voltage on pin # 30 of the fuel pump relay. The terminal numbers should be stamped on the relay socket. If you disregard the two parallel terminals on the sides, and the center terminal if there is one, the two remaining terminals will form the letter " T". One of those is terminal # 30. If voltage is there, try to determine if the relay is clicking on for one second when the ignition switch is turned on. Holler back with your findings.

Caradiodoc

Caradiodoc
Mar 11, 2010.
I just reread your last reply. If you ran a wire from the relay to the pump, and the pump ran, that rules out the fuse. Did you connect it to the switched terminal, # 87, or the hot terminal, # 30?

If you used terminal # 87, that proves the relay is turning on. The wire must be broken between the relay box and the pump. There is a connector in the circuit.

If you jumped from terminal # 30, which always has power, we have to determine if the relay is turning on.

Caradiodoc

Caradiodoc
Mar 11, 2010.
I have the same problem the truck would just turn off running and would not turn bac on for hours I also bought the gas pump, crank and cam positioning sensors and the diagnostic computer was reading clogged catalytic converter or vacume leak, my truck is a 2003 with 74k mles. In my case apparently it something loose in the fuse box. I just dicovered this a few minutes ago it started to rain while I was working on the truck and the wipers wouldnt start nor the truck would turn on but it would crank. I accidentaly tapped the fuse box and the wipers came back on and I tried to turn on the truck and it turned on instantly. Now I noticed thatt if the wipers dont work the fuel pump wont work either. Im not saying that the wipers have to be on for the pump to work but when I see that the wipper stops working so will the pump. Im going to look around the fuse box and see if I see something loose.

Tiny
Dannygar 613
Jun 1, 2012.
Dannygar, let us know if a schematic might help and one of us will see what we can dig up for you.

NickDavis: What was the verdict on tracking down the stuff cardiodoc mentioned?

Rivermikerat
Jul 30, 2012.