Need help. '94 4.0L 2wd auto died and won't start.

Yes crank shaft position sensor on the bellhousing.
I know it won't read if the distance is not correct, just felt around under there today and felt the lack of upper bolt.
So I will make sure it has two of them in place before continuing.
From what I read, the other one may be within the bell housing as well.

we can only hope not.there may be an access door on the bottom. not sure about that though.

When I left work this morning, I went straight to my shop and started on the Heep.
I removed the torque converter inspection plate and the bolt wasn't in there.
Pulled the other one out and ran to town, ended up being a m7-1.0 20mm long was the closest match.
The threads and length were the same just want made like the old bolt to hold the sensor in the correct spot.
Anyway, tested the sensor and it passed surpisingly.

Installed it and hooked up a switch so I could start it while being present in the engine bay.
Also had to repair the 02 sensor wiring which looked like it may have caused a problem itself.

Had power going to coil but still wouldnt start?
Checked everything over once more.
No codes present, fuel pump was working.

Checked cam sensor in distributor, checked cap & rotor.
Stood there scratching my head like wtf is the deal here.

Anyway, ended up being the plug going to ignition coil, the green/red wire pin socket would push out of the plug when I went to insert it.
Replaced it and she is running again.

I tried to go without the extra ground.
I ran a wire straight to the pcm plug, about 6" of the original wiring is left, from the spot where I spliced at the IAT sensor again but it doesn't work.
Will only work if I chassis ground the sensors.

Pulled the plug off of the pcm and cleaned everything up but no luck.
I'm thinking maybe the pcm has lost its ability to ground the sensor loop.
Runs great the way it is but I'm a little concerned that the pcm may be interally damaged.

The body ground and the ground at the pcm are the same. Sounds like you shorted out and maybe burnt the trace in the pcm. Just make sure all your wires are looking good and no bare spots. Looks like you spotted the o2 sensor wires damaged. You should be good to go now.

I'm kind of leaning towards the 02 sensor wiring being the culprit.
There was over 1" of bare wire on all 4.
I've never seen such a poor splice job before.

Either way, happy to see it running.

Thank you for your help.

Glad I could help