For trucks with port fuel injection, you might be able to convert it to OBDII..... but, not a trivial exercise. It involves replacing the entire under hood wiring harness, and adding the wiring for the OBDII port inside the truck. Some re-pinning of the bulkhead connector will also be required...... It's not too bad on the full size trucks. The instrument cluster didn't become purely computer fed until 98..... so, 96 and 97 PCM/Wiring harness would swap in, and boink, ya got OBDII, and a programmable PCM, that is FAR more available then the OBDI fellers.....

 

BUT... Doesn't an OBD2 system usually expect some more sensors? Such as a second, after cat O2 sensor? Mass air flow comes to mind also, along with a slew of other sensors and components I can't think of offhand. I bet that would be a horrible job.

 

I agree 100%. The plethora of iterations of the same year truck would seem to me to make creating a test rig for our ECMs difficult to impossible.

 

OBDII does want a rear O2 sensor, to monitor the cat, but, weld-on bungs are a thing... aside from that, it uses all the same sensors as the OBDI system.