Changing '95 993 Motor to OBD2 brain? Doable? Options

[SirAndy]

My '95 993 Motor is a pre-varioram OBD1 Motor and i have been toying with the idea of updating it to OBD2.

There was, for a short time, a OBD2 brain available for the (still aircooled) 993 starting in '96 with the varioram version of the motor.

It is my understanding that besides the tubes inside the intake, the two motors are pretty much identical.

I wonder if i could get a later brain and harness and make it work with my engine.
Is there anyone out there who has tried this?
(IMG:style_emoticons/default/idea.gif) Andy

[r_towle]

Andy,

the system will be monitoring fuel, emmissions, throttle position, air flow (inbound), head temps, ambient air temp, and probably a few more I cant think of.

It will need two 02 sensors, on on each side of the cat.
They are different, so research that.
the front one gives a variable signal, the rear one has a target of a constant signal.
Its in a range of 0-1 volts...
Its pretty well documented.

Each ECU is different and each car uses simple basic sensors that send 0-1 volts in a specific window...like 300 milli volts to 350 millivolts if the car is at the perfect operating temp.

As long as you have all the right sensors, it should work.
You can fool the ECU with resistors to get the reading in the right range.

Rich

[SirAndy]

Andy,

the system will be monitoring fuel, emmissions, throttle position, air flow (inbound), head temps, ambient air temp, and probably a few more I cant think of.

It will need two 02 sensors, on on each side of the cat.
They are different, so research that.
the front one gives a variable signal, the rear one has a target of a constant signal.
Its in a range of 0-1 volts...
Its pretty well documented.

Each ECU is different and each car uses simple basic sensors that send 0-1 volts in a specific window...like 300 milli volts to 350 millivolts if the car is at the perfect operating temp.

As long as you have all the right sensors, it should work.
You can fool the ECU with resistors to get the reading in the right range.

Yes, i believe there was also a secondary air injection system on the later models. I might have to fool some of the sensors. No Cat, just headers. Adding a second O2 sensor is easy, but i have to look into the different signals.

I'd probably just switch to the later upper intake to get the tubes inside the plenum.

What about the dashboard interlock system? Was that part of the main brain? If so, can it be disabled?
(IMG:style_emoticons/default/idea.gif) Andy