Attempt to convert 1995 Monte to OBD II

[Robb235]

Ok, so I was looking at this thread here by Manitcor: http://www.60degreev6.com/index.php?...ewtopic&t=3149

However, I won't be needing new injectors, a T65-HD transmission, or a new upper intake manifold, correct?

So that means I need an OBD II computer, a wiring harness, EGR, MAF sensor, and a second O2 sensor?

Now in the thread listed above, Manitcore stated he would need "ODB2/3400 Injector Harness" and "ODBII Engine Harness (sourced from an 00-02 MC LS)". What exactly is the difference between the two?

What year should I get the computer and wiring harness from? Obviously a W-Body car (and probaly a Monte Carlo?). And if say the computer is, for example, from a '97 car, does that mean the wiring harness too must come from a '97?

So do I have everything I need after that?

And once I do have everything I need, how do I go about putting in the new computer? Do I take out all the wires to the sensors and completely rewire them with new wires or do I cut and splice wires? I'm really unsure how to go about this so any help is welcomed.

[bszopi]

Why go to OBD-II? Why not goto OBD-I so you can (with a little learning curve) tune your own chips? If you goto OBD-II, you must have DHP do a custom program for you (~$300) and it'll only work for your current setup. If you do any upgrades, you would need a retune for full potential (another $300 each time). If you went to a PROM'd OBD-I, you could be tuning yourself whenever you want for around $200. And, you could program a couple different chips (economy, everyday driving, track, etc) and swap between them whenever you wish.

Just a thought...

[Robb235]

That's an idea, however, I was planing on purchasing a DHP Powertuner so I could tune my car myself. I don't really know a whole lot about converting to either, but since I did find more information on converting to OBD II, I figured that would be the route I'd take.

[bszopi]

I think all my converting info was on the old forum, therefore lost forever...

[Robb235]

Alright, so are you suggesting that it would be easier to convert to OBD I instead of OBD II?

Also, not to veer off topic to much, anyone have any answers to my original post?

[SappySE107]

Pretty sure all sensors will work, with the only questionable ones being the IAC and coolant temp. I dunno when they went with the 3 wire coolant temp sensor (instead of 2 sensors, just 1 that reads to the dash and the ECM). The IAC changed on the DOHC for 96...so thats why I mention it as well. Don't rewire the whole thing, just get the wiring diagrams and splice the current harness into the OBD2 connectors...adding whatever is missing. The EGR changed, so you will need a new plenum, or an EGR adapter, if anyone has something to put the new sensor on the old style. Not many people go from OBD1 to OBD2 because its more expensive to play with the computer.

OBD1 would require you to use the MPFI injector harness, or at least just the injectors themselves. You wouldn't be using the SFI sensors on the engine, and no more heated O2 sensor. Otherwise, its the same type work as going to OBD2...splicing in the wiring to the older plugs.

[Robb235]

Where do I find some diagrams of the PCM's?

The ones in the attachments won't help me when I'm trying to figure out what wire is what when I'm actualy looking at them.

EDIT: WTF? How do I attach stuff?

[SappySE107]

Don't use the quick reply.

[bszopi]

https://www.alldatadiy.com

You'll probably have to spend $35 unless you can find someone with the diagrams. But AllData is well worth the $$ (IMO). Its initially $20 for a year subscription for a single vehicle, then $15 for additional vehicles. When the year runs up, its $15 to renew each vehicle.

[Quintin66]

I got a subscription for a 1999 Grand Am SE, the donor car for my Engine, Harness, and PCM. I couldn't believe how complete they're info was. They have the COMPLETE manufacturer's engineering data on everything to do with the car. Every wire is catalog'd. All pin-outs from the PCM, BCM, etc, etc....Wire colors, circuit No.s, pictures of EVERY connector in the entire system, what wires go to each connector, and even a short description of what each wire does in the circuit. I have never seen or heard about so much valuable information in one site. If your going to attempt this conversion, it's the place to go. After doing so much research on my swap, I did realize ONE valuable piece of info, try to keep all your swap parts coming from the same car. If your gonna get a computer from a certain car, get the wiring harness also. The more PLUG-N-PLAY you make it, the easier it'll be on ya....................Quintin

[Stevesr]

I don't mean to highjack this thread, but it does bring a coulple of questions to mind. I'm doing the 3.1 Porsche914 swap.I have OBD1 and plan on the 3100 top end swap(right Brad?) can I use the fuel rail I have or do I need the one from a 3100? And If I need a different one will my harness work?........now back to your regularly scheduled thread.....

SteveSr

[Robb235]

Ok, I talked to a guy on ClubGP.com thru AIM. It looks like all I need to do is take out the old wiring harness and computer then put the new wiring harness in, hook all the sensors and plugs up and repin the C100 connector. I will need some new sensors, so I'll prolly need the following:

1. OBD II PCM (1999?)
2. Engine Wiring Harness (1999?) (Must be same year as PCM)
3. EGR block off and spoof
4. O2 spoof for the 2nd O2 sensor
5. Maf sensor
6. IAC or Coolant temp sensors? (Anyone know anything about this?)

Does it look like I'm missing anything? And does anyone have anything else to add?

[Robb235]

I may have run into a snare here, you guys tell me what you think.

I was talking to Germ on AIM and he said (though he wasn't entirely sure) that I couldn't used a '98 - '99 PCM because the internal wiring in those transmissions were different therefor a PCM from a '98 - '99 wouldn't match up with my '95 (4T60-E) tranny.

Anyone know anything about this?

[bszopi]

Very good chance about that. I know that just in 94 there were 4 different wiring configurations for the 4T60E.