Running OBDII PCM and OBDI Knock Sensor...

While waiting for repair of my OBDI PCM I've had to move the car a couple times, so I reinstalled the original OBDII PCM and it seems to be okay. Starts fine, idles fine, never took it above 1500rpm while shuffling it around. How bad could this be for the car? I assume the PCM is getting wrong feedback from the OBDI knock sensor still in the block, and at the worst pulling more timing than necessary, but is that all I have to worry about?

I don't think it would cause a problem, especially since you really didn't get the rpm's very high but Doc or Injureer will probably know for sure.

The PCM will apply +5V to the sensor, and since your 93-95 sensor is only 4Kohms, and the PCM is expecting 100Kohms, the current/voltage will be too high and it will assume the sensor is defective, ignore it and go to an internal "default" retard algorithm... retard is still variable, but calculated very conservatively from the engine operating conditions. Will not hurt anything except WOT power output, and it doesn't sound like you subjected the car to any sort of loads.

I would just pull the connector off the KS until you get the OBD-I PCM installed.

Thanks Jeff and Fred :) Steve said my PCM should ship out today and be back tomorrow, so I'll be able to drive my car again! Lots of mods to finish installing.

Now to find a Mallory ignition harness for my 96 coil...:confused:

I've heard that there would actually be no code from running an OBDII with an OBDI knock sensor. It supposedly thinks the knock sensor is "silent" and would be constant at 0* all the time...
I've actually started my car with an OBDII and reved it a little bit. Worked perfect.