I'm trying to find a writeup on the size of resistors and where to attach them on the OBDI PCM.
Let me know.
Mike

 

Hi Michael,
you emailed me but I didn't have a chance to write back yet. Anyway, I can answer this question for you here.
What are you converting from OBDII to OBDI? Impala or F-body?

 

96 Impala converting from OBDII to OBDI.
I don't have to change tach drivers as I have converted to a Z28 cluster. Just need to verify that I need to short pins 21 and 22 together and then put a 2K resister to ground from those pins.
Mike

 

Tach drivers???? That's a new one to me...
But yes, you have the right info for converting an OBDII Impala to OBDI>

 

Yeah the tach signal on a 96 Impala SS is a 4 cylinder tach pulse instead of an 8. If I just hook up a PCM directly to the factory tach it will read twice as fast.
Mike

 

The 94-95 knock sensor has a different impedance than the 96-97. So, if you
convert your 96-97 car to a 94-95 computer you either need to replace the
knock sensor(s) or solder the 2K resistor across the 94-95 knock sensor
pins....