hey everyone. i am not new to searching this forums for answers. every one here seems knowlegeable and helpful. this time i cant find any information that will help me so i suppose its time to become a member and start a new thread.
two months ago i replaced the fuel pump in my 2001 ram 2500 360 gas with a junkyard part that i pulled myself. all has been fine since then until two days ago. i pulled up to a friends house and went in for ten minutes and came back out. went to start truck and she wouldnt. turned the key to "on" position and didnt hear the pump turning on and priming. i figured junkyard part may have had
about as many miles as my truck (206,000) and pump took a poop. went out and bought a brand new pump yesterday and installed it. still nothing. no sound and no pressure in the fuel rail. i started checking relays like asd and fuel system they click as they should when key goes on. even switched them with one that were for sure good like the horn. all fuses under dash are good. chasing on hell of a gremlin here. dont know where to go from there. one more thing...it seems like the float on the pump is getting power. even with fuel system relay out....? thanks in advance for any help.

 

Ok, at the fuel pump, dark green, with black trace wire is 12 volt supply for the pump. Dark blue with white trace is power for the sending unit. This comes directly from the PCM, so, not really a surprise it has power, even though the pump itself may not. Black with light blue trace is is modified voltage FROM the gauge sending unit, that the PCM uses to determine how much fuel is in the tank. Black wire is ground for the pump. Ground wire runs up to the bottom of the cab, basically under the drivers feet. Put a jumper in place of the F/P relay, and then verify that you get power back to the pump, and that the ground is good.

 

how do i jump the relay? all i know about those relays is that only two pins in the relay receiving female part are hot with key "on". can i run power to main pump power and sending unit directly from the battery? obviously not the variable voltage lead because 12 constant would probably fry it.... can i hook it up to something that is ignition switched? that would bypass whtever is wrong. as far as mechanical things go i am pretty proficient, can figure about anything out but when it comes to electrical problems in newer vehicles about all i am good at is car stereo. maybe u could bless me with some dum-dum directions and i can figure it out!

 

If you look at the bottom of the relay, (and sometimes, in the socket as well...) the terminals are labeled. You want a jumper wire (just a short length of wire you can stuff into the terminals in the PDC) to go from pin 30, which is main power for the pump, to pin 87, which is the wire going TO the pump. That will bypass the relay, and you will have constant power at the pump on the dark green/black wire.

 

After checking all this, check the connectors. May have wiggled loose which may explain how it was working.........and then just would not run after shutting down.

 

looked at the bottom of fuel system relay and it is labeled 1-5 it is a rectangle shaped relay. the starter relay, which is a square shaped rely has a 30 and 87 printed on it.... all the square relays do. all relays are 5 pin so can the numbers on square relays be applied to the rectangle ones? if so, it would basically be bridging the two center pins.....

 

You can also get a picture of what it looks like on the bottom, with the pins labeled, in the FSM.

 

dont have a service manual. wish i did. is that a yes on bridging it?

 

You can download the FSM from the faq section here. Make sure you get the right pins.

 

found the issue! where harness comes out of pcm and goes down to clip to back of truck a wire was damn near severed. behold, it was the dark green and black pump supply! got the truck without wheel well shields and maybe a rock hit it. soldered together split wire and now pump is spittin... Big thanks to "hey you" for puttin up with my questions.