1997 4.0 SOHC PCM swap

[allmyEXes]

I just purchased a 130K mile '97 with the 4.0 SOHC and was wondering if I can swap its PCM with my '97 4.0 SOHC (Flo) for diagnostic purposes. Flo's PCM has been acting up. Everything from at start up it acts as if the battery was just undone to the auto door lock/unlock feature sometimes locks after putting in gear and sometimes does not and the fuel gauge sometimes reads below empty until it is driven a mile or so. I have unplugged the two connectors under the hood and the fuel sending unit issue fixed itself initially after doing so.
The "new" Ex doesn't exhibit those issues so I want to do a direct swap for diagnostic reasons. Thanks for any input

 

[410Fortune]

yes
PCM should be the same 97 to 97

However the stuff you are talking about is not controlled by the PCM rather the GEM
So maybe you should swap the GEM from 97 to 97 and see if that helps

Gem modules are truck specific, meaning 2 door, 4 door, 4x4 or not, etc so both trucks should match as much as possible

 

[allmyEXes]

ok, thanks. Ive seen mention as to where the GEM is located.

 

[410Fortune]

next to the stereo behind the 4x4 switch

 

[donalds]

I found a couple bad solder joints on mine fixed her rite up

 

[allmyEXes]

Is that the GEM module ? (If you can) Draw a circle around the bad solder joint. A few minutes ago I started removing the white '97 PCM but stopped when I needed a 11mm socket. I was trying to do this in the driveway at home and all I have is a partial tool kit at home. Time to put together another tool box

 

[donalds]

My problem was a interior lighting issues
Look the whole board over
My kindle don't have the ability to edit a circle in the pic

I'm sure you can see the bad ...cold... solder joint

And yes it's the gem in my photo

 

[allmyEXes]

Follow up...After swapping PCMs with the engine cold and warmed up, I think that I may have a vacuum leak occurring when the engine is cold.

 

[410Fortune]

Okay
A new PCM will act funny for a few drive cycles, the computer thinks the truck is brand new anytime you disconnect the battery so it will try to "learn"
This means the idle may be a little high and a little strange for a bit but it should settle down

What makes you think your 97 is having a vacuum leak?
Being a 97 SoHC engine unless you have done some gaskets recently I bet it does have some air leaks.....

 

[allmyEXes]

I can hear a leak when it is cold even though I can't locate it and in late summer 2017 when I removed the upper intake to access the plastic thermostat housing to replace it, I didn't replace the o-ring gaskets between the upper and lower sections of the intake assy.

 

[410Fortune]

REPLACE THEM!!
They are dried up and not sealing I can guarantee it

If you want to see where the leaks are around the intake use a flashlight and look for a build up of dust and dirt around the base of the plastic plenum

 

[allmyEXes]

TFTI ! (Thanks For The Information !)