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In regards to viewtopic.php?f=12&t=485

I never installed OBD2 on my '94 SSE. I had planned on it, but I decided to sell it and get something newer instead (the '97 SSE). I did, however, do two more conversions for jrs3800...one for his '95 Transport, the other his '95 SE. The van I did about 3 years ago, the Bonneville about 2 years ago, both are still running and driving and fully tuneable with either HP Tuners or DHP. Both of them got the PCM installed inside the cabin, each wire being cut, soldered, and heat shrunk to the PCM plugs, and new wiring ran when needed.

Both Don and myself noticed an immediate difference in the way the engines start, idle, and drives down the road. It's a vast improvement for the L27 (and the S1 L67, which was the first to receive the transplant), but since each vehicle is different there really is no way to make a PnP harness. Also the fact that there simply isn't a huge demand, as many of the 95-down vehicles are either well on their way to the scrapyard, or are already there.

So would you recommend using the existing engine harness and just soldering the new computer in? Will this affect my gauge cluster or heater/ac or radio or any other accessories in any way?

I'm basing what I am about to say completely off of memory. The notes I took when I did the research and actual conversions are lost in the sauce.

As far as losing anything, you won't lose much if anything at all, depending on the model. If your car is currently equiped with T2V (variable assist steering), you will lose that function as the OBD2 pcms used Magnasteer. For a/c, you can configure it however you want...you can run the HR6 or the V5 compressor, whichever one you want to run. If V5 you will need to wire in the AC pressure sensor since the '95s just use high and low pressure switches. If HR6, program out the codes for the pressure sensor.

Gauges...nothing to change. OBD2 1997-up computers have PWM fuel gauge, hence the change in sending units that year. You will not need the gauge input/output on the PCM, so those circuits get deleted and codes disabled.

Transmission...here's where it gets interesting. You will need to locate a 1997 PCM to make things easy, as the L36 still had the 4t60 that year. Not sure if you are an L67 or an L36...if you are an L67, you will have a little more work to do. If you are, I'll elaborate later. If you are an L36, you're good to go. If you have performance shift on your car, you will lose that if the car the donor pcm came from doesn't have it. There are ways to enable it, but it isn't anything HP Tuners is willing to implement.

You will, in addition to the PCM, need the cruise control module. You will also have to wire that in.

You will need to pass wires through the firewall. I holesawed and added a grommet in my conversions. Cruise control, ac, MAP, and a few other circuits will need to go through.

Now...was the conversion worth it? I'd have Don tell you, but he's been very happy with the conversions. The van was out of necessity since an L26 went into it, the car was experimental but proved to control the engine and trans much better and more predictably. Having the ability to tune at a whim is a bonus. But the best part was not having to worry about the crappy 94-95 pcm ever again.

IMO an OBD2 conversion on a 94/95 is a lot of work for something that has on the fly tuning capability.