I need to know if the ECM needs the factory alternator to function properly.

I am moving my alternator up to the AC compressor location and realized that the alternator that came off my 93 explorer will nearly bolt onto the AC bracket. just have to make 2 simple 90 degree brackets and one of the holes lines up perfectly.

Wiring the Ford alternator is easy, so no worries there

 

anyone?

 

I don't have FSM's for 89-92 so I don't know when they made the change over. 93's used the PCM controlled Nippondenso alternators and the 88's use the internaly regulated Delta alternators. So if your 91 (I assume) uses the Delta then you'll be ok to use the Ford Alt. If it has the Nippondenso Alt then the PCM will illuminate the "Check Engine" light. I can't say if it will go into limp mode because of it or not.. I would think no, but not for sure. Why don't you just get a Wrangler or ZJ accessory mount? I'm almost certain they have the A/C and Alt mounting locations reversed.

 

1984-1986 had the Delco 12SI - internally regulated.
1987-1990 had the Delco CS121 or CS130 - also internally regulated.
1991-2001 had the Nippondenso in the smaller frame size - externally regulated.