Still No Spark!!!!!

OK guys.. I'm stumped...
I have the 94 YJ with a 2.5 4 banger that was rescued out of the farm field that I am getting back on the road with my son. He is 16 and his first truck.
Here is what I have done......

replaced the:
distributer
cap
rotor
plugs
wires
checked primary and sec res of the coil (all check out)
Had the PCM repaired.(it was pretty smoked).. I just today made him recheck it and show me the results from a known good PCM.
checked continuity of all wires having anything to do with the ignition
replaced crank pos sensor. Would a bad cam pos sensor cause no spark?
I do have voltage from the batery to the PMC.
the rotor does turn. (been asked that a couple of times)

I get no signal to the coil and therefore no spark. I also can't make the PCM to go into self diagnostic mode and flash codes on the check engine light.

I'll have to admit I'm pretty frustrated. Anything you good people can pitch in would be a help...

Thanks

[LEVE]

Bad Crank and Cam sensors should throw a code and shud down the ignition and fuel. So first check to see if there's voltage on the coil. If there's no voltage on the coil the AutoShutdown realy is not being told to engage, hence... Auto Shut Down. If the AutoShutDown relay is enabled, then you should have voltage to the coil, and to the fuel and ignition system.

However, if you can't get into Diagnostic Mode, my guess is that you're missing a major voltage input.

Hello Leve
I am NOT getting voltage to the coil. I did replace the relay to the emergency shut off. This was one of the first things I thought of. I don't know much about the shut off. I guess its working on a mercury switch? It has nothing in the manual about this subject. Were is the switch located and is there any way to bypass it? I have voltage to the PCM from the battery and have ground from pins 11 and 12. There is no other power input to the PCM.
When I got the PCM repaired and still didn't get any spark I took it back and the guy that fixed it got me a known good PCM. He hooked it up to the test jig and the output was the same from mine to the known good.
Any other reason that I can put it in self diagnosis mode? Any other good tid bits I can check?

[carnuck]

Rollover switch! Not sure where they put it on that rig, but it'll cut fuel and spark in the event of a rollover and need to be reset.

[LEVE]

Originally Posted by wr400f

Hello Leve
I am NOT getting voltage to the coil. I did replace the relay to the emergency shut off. This was one of the first things I thought of. I don't know much about the shut off. I guess its working on a mercury switch? It has nothing in the manual about this subject. Were is the switch located and is there any way to bypass it? I have voltage to the PCM from the battery and have ground from pins 11 and 12. There is no other power input to the PCM.
When I got the PCM repaired and still didn't get any spark I took it back and the guy that fixed it got me a known good PCM. He hooked it up to the test jig and the output was the same from mine to the known good.
Any other reason that I can put it in self diagnosis mode? Any other good tid bits I can check?

Replacing the relay is different from understanding why it does not engage. Here's the scenario: The fuel pump should run fro 2 seconds via commands from the ECM. After 2 seconds, the ECM shuts down the fuel system and the ignition system if no pulse is seen from the CrankshaftPostionSensor. The CPS (or TopDeadCenter) pulse MUST be seen for spark and fuel to get to the engine. The ASD relay engages and sends 12 volts to the fuel pump and the ignition. That feed point is the coil voltage I mentioned. So, if you've got 12 volts there after 2 seconds of engine cranking... in START mode, then the ASD is working, as is the CPS and the ECM. If you don't have voltage being fed to the coil... so you need to check if there's 12 volts on the coil.

Start there... Send me an Email ( lvevery@gmail.com) and I'll send you a section on an XJ 2.4 engine in PDF format (should be the same as yours) that will help explain stuff better than me.