Engine/Transmission (1994 - 1998) First Crank sensor, Now PCM issues

[triggamike]

Hey I'm new to the forum. Read a lot on here but never posted.
I just picked up a 98 12 valve and it's got some issues that I need to work through. I'm buying a bunch of stuff to bring her back to life.

Well first thing I'm trying to work on was no gauges, no charging, no Ac compressor....etc. crank sensor (ess) right? Well, finally got my crank sensor today and swapped it out. Gapped it at bout .049 like everyone says. And I went to check gauges and still nothin. I checked voltage a few days ago at the plug and had 5.3v on both the outside wires and nothing in the middle. I figured was supposed to be the pulse. Well today I had 5.3 on one and nothing on the other two wires goin to the crank sensor. That's with the new crank sensor. Well the guy I bought the truck from had 2 pcm cuz he thought pcm might be bad. So I was scratching my head and figured I might try with other pcm. And I did, and boom all the gauges worked except speedometer(probably a diff issue). So I went and took it for lil drive to see if it would get outta limp mode. Cuz it was stuck in 2nd or 3rd. Now stuck in first. But that's another days problem. Anyway. No charging from the alternator. If I swap back to the other pcm then gauges don't work but alternator does.

So long story short. After I changed the crank sensor.
Pcm#1--no gauges--alternator charges
Pcm#2--gauges good-- no charging

Do I just have 2 bad pcm's. After everything I read for the last few weeks it seems like it's always something else besides the pcms.
Any help?
Sorry for the essay

 

[Bob4x4]

Aftermarket pcm's have a bad track record,but we don't know the origons of either of yours.

 

[BFurton]

Sounds like it could be either a "grounding" or "power distribution" issue. Could also be defective or bent pins in the connectors @ the PCM.
In the wiring diagram, there is a fuse F14 that seems to commonly feed much of the instrument cluster...

 

[triggamike]

Well. Since the problem followed the pcm and wasn't constant I changed pcm and the one I had with everything working didn't regulate the alternator so I put an external regulator and I'm good to go. I went with external regulator cuz the other pcm regulated the alternator just fine so with this different pcm I'm using it should also. But must be burned up. Anyway. Good to go now. Thanks for the replies. Here's the part numbers at autozone if anyone interested. Ran out of wire and didn't finish cleaning it up in picture. Just wanted to make sure it worked. Was late at night#ad

 

[Missouri Mule]

On the ess one of the wires is a ground wire, power wire and the other turns on the asd relay(sends line voltage readings to pcm) and lets the pcm know the engine is running. I pulled out the asd relay once and voltmeter was registering voltage and the engine kept running so there must be a split in the wiring some where down the line. There is a battery temp sensor under the drivers side battery that can cause problems.
The evr (electronic voltage regulator) inside the pcm can fail but usually pretty reliable.
Seems you have two bad pcms. Other members have put on external voltage regulators.