OBD-I to OBD-II

[RockinExplorer]

has anyone done this and how hard is it to do

 

[410Fortune]

I did it. really hard.

What are you asking? You want to convert your current engine/drivetrain to run with an OBD-II computer?

May/May not be possible, depending on what we are talking about.
With your 95 model year I can see this happening possibly, but we need details on what you want to do, to which truck, and why?

 

[KPT]

I was considering this for better diagnostics and so I could get one of those displays with OBD II info in the truck. I have a manual transmission so that would be one less thing to worry about.

Is there any real benefit though?

 

[RockinExplorer]

i am doing this because this summer i'am going to do a complete rebuild on the motor, put a supercharger on it and put a manual tranny in. And i want to have xcal2 so i can tune it anytime.

 

[410Fortune]

Take a look at the features you want to be able to tune with your new tuner, what is the best year of the 4.0L OHV computer for tuning?
Dont forget in 98 they all have PATS, so that becomes an issue.

What I am getting at is it may be really simple to replace your 95 PCM with say a 96 PCM, but the 96 PCM although OBD2 might not do as much as you think it does when it comes to the tuner.

So lets say you use a 97 computer in its place
Your 4.0L its self may have a couple/few sensors that will need to be changed out, maybe not. You will have to do some research. On the engine itself it is not likely, however the OBD2 PCM may use a digital crankshaft sensor (instead of analog) this kind of thing. This will depend on what PCM you get and what that year engine used.

The emissions system (EVAP) should be a real similar setup to your truck.
Your 95 has 4 02 sensors already does it not?

When I went from a 93 4.0L PCM to a OBD2 97 PCM I added the following to my truck to make it work:
fuel tank pressure sensor
EGR
4 ea 02 sensors

and I kinda "fudged" the EVAP system to eliminate a bunch of the hooey my 88 never had anyways (chacoal canisters, solenoids, etc)


thats about it!

best place to start?
Get the pinout for your 95 PCM 110 pin plug and then compare it to the PCM you want to use (97 4.0l OHV, 5 speed) and see the differences in the wiring.

 

[KPT]

95's have two oxygen sensors. I'm assuming the right value resistor would make the computer think the downstream O2's are fine, since they don't affect air/fuel anyway.