Huh didnt know any of that! I think it will just stay put then . I really just need to get some larger injectors so i can replace my fss im kinda gettin tired of havin to reach down and pull the goofy cable.

 

The only extra thing for the auto is OD control. There's a couple diferent ways to do that. All you need for a stick is the grid heaters (which some people just delete anyway) and speedometer, which is one wire grounded. The PCM in these trucks is realy quite primitive. That's probably why you've been told they are not rebuildable. Nobody is going to waste time stocking parts or training techs for this ancient junk.

 

So I know it's 4+ years later on this thread, but since I now own a 91.5 that nothing works on, (A/C,speedo,,O/D, etc.) I have assumed it's the PCM and would love to know how to get it to work w/o it OR purchase a known good one. I actually know the deal with the trans and the potentiometer, but how would you make the speedo, & A/C work. etc. thanx , Crossy work?

 

This is good a place to start as any:

91.5 PCM Pinout