Remove the PCM connections and spray them out with contact cleaner before replacing PCM.

 

Swapped/cleaned relays. Battery cables brand new. Battery not so new. I'm going to swap the battery for another tonight

 

OK. I'll knock that out later.
Today it was about 88°F here and it wasn't doing it all day. As far as the CEL and pump priming goes. Rough start is still there.

 

Do I have to somehow discharge the PCM before cleaning the contacts on it? Bought some contact cleaner and it says to make sure whatever is being cleaned has no current.

Was thinking of POS cable to block for 30...?
Or am I good to just disconnect the cables?

 

Just disconnect it.

 

Sounds like your connections could use some cleaning. Like cruiser said, pop stuff apart, scrub with a brass wire brush, rinse with hexane electrical contact cleaner, reassemble. For every single connector you can find (obviously you might have to use different brushes)

Note that dielectric grease should not be applied on the actual conductors. It's supposed to be used like caulking to seal around the edge and keep water out. On the conductors themselves you want a product like Gardner Bender OX-GARD or Ideal NOALOX

 

Well, after a long 50+hrs of no sleep, and a LONG night a the woman's, I made it to my local yard. They had 4 XJs, 92-95 which was perfect so ended up grabbing a PCM from a '92, the same XJ I swapped clusters with. $39 bucks.

Got it in. Now it CEL lights up at the turn of the key
Thanks for all your help gentlemen. Lock em 'n load em!