2005 jeep gc with 4.7l V8 - no fuel pressure but new pump
 

Hey guys
I am peter and actually a Ram truck owner(and forum member)but thought you guys might be able to help me.
I am having an issue with this jeep.Came in no start but cranks good.Found no fuel pressure check relays and fuses all good.Removed fuse boxs and there she started working.Now I cant get it to stop working.Owner toke jeep home and it did it again.He said he just pushed down on rear fuse box(one by abs motor) and it started and ran ever since.

checked: Fuse,Relay(swopped out),Wiring from pump to pcm,Wiring from pcm to fuse and relay,

I need help as I am in a GM shop
thanks guys

I don't think there's an easy answer for you, if the problem manifests itself when you move the fuse box, that would tell me that there's a connector or wire connection problem in that area. This can amount to a wire-by-wire check to find the problem & if you have a multi-meter and a wiring diagram available, this should make the job easier. The wiring diagram should give you the pinouts & connectors that you should be looking for to do your testing. I would look for physical damage like bent pins, loose wires, etc. & most likely need to perform some continuity tests on each of the wires involved in energizing the fuel pump. In some cases it would be better if the pump wasn't running, then you could test the line (using the wiring diagram) for where you stopped sensing any voltage and then you'd have found the wire segment - you'd then need to look over that wire connections to determine why it got volts at one end and nothing came out the other.

If the pump keeps running with the key off, you need to look at the ignition switch wiring - if this goes to the same fuse box, I'd be looking for the problem around there. Essentially you need to find out why the fuel pump relay doesn't deactivate - I think the problem is between the relay and the ignition switch, in the area of the fuse box.

The basics of how a fuel pump hooks up to a wiring system is pretty much the same on all vehicles, so your trouble shooting techniques should be the same. The differences will be in the wiring, connectors, and other assemblies involve - for some help in this, you should download the service manual available on this site and have a look. These days the manual content isn't much different either. The other option is to call a Dodge dealership and talk to a mechanic there, they could give you the connectors & pinouts all the stuff you need to look at.

I hope you aren't charging the customer for giving him his problem back.