changing from OBDI to OBDII

[95slowta]

I have a 95 Trans am it has the OBDII plug but its OBDI, could I just simply tune a 96-96 OBDII pcm and plug it in. or would I actually need to change other things also?

[Wilburbeest]

EDIT: nevermind, i was thinking of going to OBDI from OBDII rather than the other way around. Any particular reason why you want to switch?

[MEAN LT1]

agree with above. Why in the world would you want to switch to obd2 of all things?

[95slowta]

because I was thinking might as well since I have an OBDII plug with an OBDI pcm. I mean I take it there are no benefits to it the way you guys are talking. I have a code reader but I can't pull codes because it only reads OBDII, and I'm the worst time figuring out whats wrong with my car. or why it will only idle for a few seconds, check engine light comes on, then it sputters a second and dies...

[rebuilt]

obd-1 is supposed to be more mod friendly. Least thats what I've been told.

[Shon Herron]

you do not have the sensors to go to OBDII, ie the CPS, but why would you want to.....

[Pony_Killer]

I think he's just trying to figure out to get past the BS obd1.5 setup he has with the obd1 pcm and obd2 plug like I have..

[Pony_Killer]

Could always get a better code reader or just do the trick with the wires that's shbox shows how to do..but I do know ur pain some code readers work and some don't..

[Camaroholic]

Honestly I wouldn't bother. ;)

I have done it though. I ran an OBDII computer in my 94 Z28. Why? Because the OBDII handled the higher stall converter (my Yank ST3500) better than the OBD1 computer did. The OBD1 computer would lose the VSS data and get all wonky when doing a burnout or hard acceleration (limp home mode and a soft shift to third). OBDII computer didn't do that. But, I much prefer the OBD1 computer. Eventually I had that stupid loose ST3500 redone to become a SY3000, and I'm back to running an OBD1 computer with no issues.

I have LT1Edit for OBDII, and I removed the codes for the crank position sensor and the rear O2 sensors. I also ran a wire out from the PCM so I could access the OBDII data with AutoTap.

I also would not call the '95 F-body "OBD1.5". That's completely incorrect. Sure it has an OBDII style connector, but the PCM has ZERO OBDII stuff inside it. It's 100% OBD1.

The '94-95 Corvettes would be "OBD1.5". They have chips inside the PCM that actually support a bit of OBDII communications, and they support a few OBDII trouble codes on their OBDII bus. (The '8051 PCM that the F-body uses does not have these chips on the board - but the spots are there.) The support is really limited, I think it was more of an experiment for GM rather than any true implementation of stuff.

[Black96z28]

the port youre talking about, is a standard port. it looks the same for Most obd1, and all obd2 vehicles.. youll be better off with obd 1.