Oh yea it's nice! lol. I got another one when i bought the battery too so I have another $20 waiting at the auto zone for me

They hates me, lol

 

The pump is running or trying to run. That is why there is a power drop. Now determine if it is running.

 

So checked the pump and it's not powering on still. However I tested this with the pump unplugged and jumping the power and ground connectors on the pump. I still read only 7.5v at the PDC, and at the pump connector. this happens if i jump the relay connectors in the PDC or if i pipe a direct 12v from the battery down the relay output. both instances we are looking at only 7 at the output, pump plugged in or not. wild....

 

I got a spool of wire to use as a jumper from the battery to the pump from someone at work today. I will try and find time to jump this tomorrow and see what happens. I'll run from B+ direct to pump and see what i get!

 

Correct me if I have missed something but have you tried something like a starting spray at the throttle body to see if spark is present?
I had starting, fuel and all kinds of problems and tried all the suggestions given here to no avail. I finally found a Dodge Mechanic that was persistant and he found the bolt that connects to the cpu was not consistently transmitting ground to the nut (had a thread problem from a previous cpu change), and the connector in the cpu was stripped. We ordered a used CPU from a Junk Yard and replaced the bolt in the harness and presto all problems solved. I now have full function of all electricals in the truck except the dome lights from the door switches.

 

Hey 89newbie, thanks for the reply!

I have tried starter fluid and she kicks right over so we know that spark is present. Good point to mention though because thats a crucial test when diagnosing this kind of issue.

I am starting to lean towards a ground issue. I have to do my direct feed test still to see what happens but i feel there is a decent chance a ground is bad since i am seeing a voltage drop of about 5v! I will try a direct feed from B+ to pump, then after i get results from that I will most likely make a ground on the frame and test it to see what happens.

Thanks for reading and for the info! i REALLY hope to get this figured out!

 

Tale tale indication, threads on bolt holding harness to CPU slight thread damage and connector not seating totally tight. Secondary problem I had was map sensor feed on throttle body being affected from carbon in the vacum tap area. Cleaned tap but carbon continued to be a problem so I refed Map sensor from capped tap on rear of intake manifold. Presto, new truck once done. Great gas mileage no problems all acessories including speed control now work and overdrive is back. LOL now if I could only stop that oil squirt from the tail lights when I hit the brakes, rofl

 

Forum,

Guess whatttt!!!!! If you guessed the trucks running, you're wrong, but only slightly.
I have come across a good bit of information today thru diags! I even made a half @$$ video of it! I was planning on keeping the video just for me to check something, but i will share it later.

So what I did was run down to the hardware store and pick up some alligator clips (and some solder, more or less unrelated but may be handy)
I made a jumper wire from some wire I got from one of the guys i work with. actually I made 2. One ran from the battery positive to the fuel pump positive, and the other ran from the fuel pump ground to the frame of the truck. As soon as I applied 12v to the pump she primed right up! I am thinking the problem I have been having this whole time is related to a bad ground. The FSM says the ground for the fuel pump runs behind the radio? whaat?! lol

Would it be a bad idea to ground the pump to the frame? say i spliced into that ground wire on the pump connector and grounded it out?

Thanks forum!

 

so check this out. When i run power through the existing wiring and ground it to the frame, i STILL only am getting around 6-7v. as soon as i use my jumper wires i can actually start the truck and let it run no problem. so this points back to a power supply issue and not a ground issue because when i tried this i was using my makeshift ground. I think tomorrow I will be buying new wire and just running a direct wire to the fuel pump. Anyone know anything about pulling the PDC apart? I want to connect my replacement wire inside the PDC.

 

Alright, update time.

Good news (more or less) i have figured out whats going on. I have determined the issue to be with resistance down the green/black wire. so here is how this works:

Fuel Pump relay runs down circuit a141 which runs along the driver side fender, up into the cab thru connector 116, does some kind of magic behind the firewall and runs out to connector 207 which then runs down under the truck and eventually branches off to the fuel pump. After c207 the circuit becomes a61. so a61 runs under the truck and feeds the fuel pump. the a61 line is my problem. there seems to be resistance along this line. I pumped 12v B+ connection down that line from the connector, and after the connector (shaved off some insulation w a razor knife) and both times i have only 8-9v at the end. I switched over to continuity and it doesnt show anything. I switch over to 2000k ohm reading on the meter and it gives me 540. Not sure what this means exactly, but it seems really wrong. No other Ohm setting would give me a reading.

Oh snap, i think we have a winner! now how do i find the bad part of the wire....... hmm. I can't seem to get the lower harness out because the connectors wont clear the cab mounts. As usual, solve one problem, have another, lol.

Alright, im off. advice always appreciated!

Cheerz