I think I might have made my Jeep mad by making an account here, it broke a few hours after I made an account. it fired up and ran normally for maybe five minutes before it died and wouldn't restart. It cranks over fine, and I heard no weird noises either before or after it died. The check engine and upshift light both came on and stayed on around the time that it died (The upshift light hasn't worked, on two different dashboards, so I'm fairly confident it's connected) I have confirmed that it isn't getting spark to the distributer, and that the camshaft position sensor is still in one piece in the distributer. Pretty much everything is stock and original, other than the transmission, which is an AX-15 from (I think) a '99, but it did have an AX-15 originally. I'd appreciate any suggestions, electronics are not something that I understand well.

 

No start, no spark? Usually leads to a bad CKP (crank position sensor).

Usually, not always.

 

Would a bad CKP cause the check engine and upshift light to come on? I tried to extract the code from it, and couldn't get anything. also, is there a way to test it without removing it from the bellhousing?

 

You can use a logic probe to test the CKP. Check for 5v key on at pin 1 (gray/black wire), ground on pin 2 (brown/yellow), and pulsing 5v at the orange wire (pin 3). The test on pin 3 has to be done with it plugged in and cranking.

 

Thank you, but unfortunately I think it's the PCM, for a few reasons: I dragged it into town today to get the check engine light code read (Completely unsuccessful, maybe if the PCM is toast it wouldn't read?), but the odometer, speedometer and tachometer (Put it in gear for a second at slow speeds, I'm not fully insane) all did nothing, so I'm wondering if I'm correct in believing that there is a circuit in the PCM that deals with the engine rotation that's fried. An additional question, would it be possible to take the PCM off of an automatic Jeep (mine is manual) and put it on to test whether or not it changes anything without damaging either the borrowed PCM or something else in the Jeep?

 

I can, with 100% certainty, tell you for a fact that it does work.

The CEL will stay on because it wants to see the automatic TCU. It also does this thing where you'll downshift and engine brake for a bit, then as you come to a stop the engine will idle at about 200 rpm. Once you blip the throttle it'll idle at normal speed again.

I've been driving that way for 2 years now.

 

Did you check all the fuses and grounds?

 

Again, for testing purposes, will a PCM from a different year work enough to start the engine? And yes, I did test all the fuses I could find and nothing was abnormal

 

Different year? That depends on the year. You'll need one from a 97 through 99

 

My Jeep is a 95, so I'm assuming that a 91-96 PCM would work?

 

So, not to be an Idiot here, but I haven't seen any posts about the "Basics..."
Clean all your Grounds.
I feel like I'm beating a Dead Drum here, but the XJs are all VERY Ground Wire SENSITIVE...
This means, if you have dirty ground wires, you will end up with weak flow to you CPU and other Sensors that make your Jeep work properly.

It's Cheap and Easy, with a Lil work, to Locate, Loosen and Clean, with Brillo, Wire bush, or Scraper, ALL of the Major Points of Contact. It'll eliminate a bunch of problems you don't Even Realize can Occur. Look Up "Cruiser54" and "Ground Cleaning"...
You're truck will start tomorrow.

My advice, for what it's worth...
DONT rewire you're whole House when a Light-Bulb burns out...

Start with the Simple Stuff...
Like GENERAL Maintenance...

 

I didn't mention it, but I did go through a lot of the grounds last fall for a different electrical issue, so I'm fairly confident it isn't that. I do also think I know where I can borrow a PCM from to test if it's the problem or not, but if that doesn't work I'll probably put grounds on the list of things to check. I'm fairly suspicious of the PCM just from the symptoms it's having and the condition of it (The case is hanging open and there's copper showing inside it)

 

Does anyone know how many grounds run to the PCM on a '95 Cherokee? I'm trying to check to make sure it's getting ground to the PCM to rule out the wiring harness before I throw a new PCM at it

 

You can download the entire 95 FSM from XJJeeps.com

 

How'd it work out? Are you up and running?