ok I found one dead fuse that I must have missed. fuse #19 it had a 10 amp in there. replaced with the same. Checked it against my other jeep and it has a 5 amp in the same spot. Anyone know what this fuse is for? Regardless. still no change.

 

ok so I checked the voltage at the 19 fuse on my other jeep. It's dead to. extra fuse?

I didn't get much time tonight too do much of anything so hopefully tomorrow I can scratch out more time between taking care of my two kids.

I was however able to pull out about 7 pounds of wire from the PO and his additions. I never really paid much attention to under the dash until the last couple days and said "holy crap". Pulled everything out from a half-assed KC light wiring harness (it actually had relays in it though) that was stuffed under the center console to some sort of big white push button that was just laying in the drivers side kick panel and was hooked into a bunch of other wires. Tore everything apart and got out the solder gun. So I guess that should eliminate SOME things that could be wrong... I hope.

Tomorrow I'm going to start from scratch and go back through everything again. I've been so focused on the PDC and engine bay that I wouldn't doubt if I skipped something. I'll start at the fuel pump and work my way back to the PDC, then from the coil and Alt and work my way back to the PDC.

Any suggestions on areas I could/should pay extra attention to?

 

Forgive me if this has been answered, but does your fuel pump spin up when you turn the key to "on"? Does the CEL turn on (bulb check)?

 

You are in supper company. I'd hazard a guess that the extra stuff is some kid trying to make allot of noise. Kids do that after they move from the shopping cart to a car.

 

My favorite is the kid who makes all of this noise all the way to his parking spot then gets ripped off and wonders why

 

On my way to a dr. appt. so don't have a lot of time to absorb all of this yet. You are certainly doing a good job on trying to isolate this.

I find it curious that the engine tries to start with the different PCM. I'd check spark quality (need strong blue) and consider having a fresh set of spark plugs to swap in and out as necessary in case the engine is flooding with continued tries to start it.

Here are a couple of links to others with an XJ and a code 42. Check them out for ideas. I'll check back in when I get back to the house (if the old Jeepster makes it through the blizzard we are about to have!!) Good luck.

http://autorepair.about.com/library/faqs/bl561g.htm

https://www.cherokeeforum.com/f2/reb...e-42-a-146735/

 

Nope. No fuel pump at all. Doesn't prime or anything.

At the fuel pump relay, I'm now only seeing 5.7v if grounded at the FP ground (terminal c20). Does this sound normal? I know a full twelve at initial key on for 5 seconds is for prime and then it drops to 6v right?

 

Thanks for the links and taking the time TJ. I'll look through those and see if they give me any hints.

 

Lol. I haven't even touched the hacked amp and stereo wiring yet. It was all auxiliary lighting, relays and who knows what.

 

I've not heard or seen where it's supposed to cut the voltage to the pump after 5 seconds. Mine sat at battery voltage all the time. Something isn't right there.
Your Fuel pump and ASD relays- do they operate at all when you turn the key?
What is the voltage across the coil terminals for each relay with the key "on"?

 

I had to take a step back from it yesterday. My lovely girlfriend pointed out that I had spent more time with the jeep or wiring diagrams over the past week than I had with her or my kid lol. Ok ok. Fair enough.

I'm heading back out right now & I'll double check everything and get some solid numbers. I'm going to start from scratch. This has to be something stupid that I missed

 

ok I checked on both jeeps, even swapped the battery back and forth so I would get the same voltage. I'm getting a solid 12v at both power terminals on the ASD (still) on both jeeps. Im getting 6.7v at both power terminals (grounded out at the relay ground) on both jeeps. For kicks and grins I swapped the relays (known to be good) from my good jeep to the one that is broke down, same thing, no start.

I'm going to crawl under the POS jeep right now and check voltages at the fuel pump and start my way back again. With everything as it is, I am convinced it's something on the fuel side.

 

so I just got back in from trying to track some of this down.

on the fuel pump side of the connector by the rear axle- kind of hard to decifer this because my connector pin-out diagram and wire colors do not match here. Black wire is my ground, the I went to the terminal just above it (yellow wire) and there I measured 20.8 ohms. Every other pin, using the same ground, shows 0 ohms. Then I tested chasis side of the connector and everything shows 0 ohms. Tested the voltage there and on the fuel pump feed I get an initial 12v that drops down to 5.7v. On the sending unit feed (fuel level sensor) I get a constant 4.7 v.

With that being said, is it possible that my fuel pump module is bad and causing all of this?

 

Anyone?

 

I'm having trouble following exactly what you are measuring. What is:
"Im getting 6.7v at both power terminals" ? What do you mean by "power terminals"? Where are they located?

Do the ASD and/or FP relays engage when you turn the key to ON?