Olds W31 Posted January 18, 2009 Report Share Posted January 18, 2009 Ok, for almost a year I have endured the bizarro transmission behavior in my 1994 Olds Cutlass. It is still running, but I know the end is in sight. I wanted to do a 5 speed swap but time, money, and location have conspired against me. A friend of mine had a 99 Pontiac Montana, with a 3400, and, I believe, a 4t65 (not certain). Long story short, it is sitting in my driveway, with the subframe dropped, and I am preparing to swap the transmissions. Why not do both engine and trans, you ask? Well, the 3400 MAY be fine, I did get it to start and run before commencing the surgery, but it has a bad water leak from the rear, which I could not find. I am pretty sure it is intake gaskets, but I would rather have the time to open it up, do the bearing and freeze plugs, then swap in a "fresher" motor. Questions: 1)Having looked at the OBD 2 harness and the OBD 1.5 goodness in my car, I am swapping the entire engine harness, but I was wondering if anyone on the board had a 96+ 3x00 OBD harness, as I might be simpler for me to use that, rather than reverse engineer the Montana harness into my Cutlass. 2)Any body have the actual wiring diagrams, with pinouts, for the body connector in a 94 Cutlass or equivalent? It would make it easier to repin and figure out what stays and what goes. 3) any other input in terms of having done this before and looking for short cuts/pitfalls, etc, would be appreciated. I will try to get pics up so that you can follow along. Let the mayhem begin! Quote Link to comment Share on other sites More sharing options...
ManicMechanic Posted January 18, 2009 Report Share Posted January 18, 2009 Find 3100MPFI on 60degree or GMWBODY.com. It make take him awhile to answer as he doesn't have internet unless he goes to his mom's house. He has done it. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted January 19, 2009 Report Share Posted January 19, 2009 or here http://www.gmwbody.com/viewtopic.php?t=835&highlight=lumina Quote Link to comment Share on other sites More sharing options...
OldSkoolGP Posted January 21, 2009 Report Share Posted January 21, 2009 Converting to OBD-II was a PITA for me, but it was worth it since I can now tune my own car. But I will say that this is the ONLY reason to do an OBD-II swap. Just changing to OBD-II won't increase performance, especially over OBD 1.5 which had the SFI and extra sensors that OBD-II gives you. The best thing I can recommend is to get a service manual for your car and get a service manual for the car you got your donor harness from. They have detailed schematics regarding all the connectors and what wires do what, what you need to keep and what can be tossed. Being a '94 car you won't have all the power wires running through the C100 that '91-93 cars have which will make your life a bit easier. You're also going to have a much easier time upgrading your tranny to a 4T-65E rather than trying to make your old transmission work on the OBD-II system. They speak different langauges, and while you can make them talk to each other, it's not worth and a 4T65-E is a better tranny anyway. Also, if you want to bypass the Theftlock, jumper Pin 55 to Pin 17 on the ECU harness. Quote Link to comment Share on other sites More sharing options...
Olds W31 Posted January 22, 2009 Author Report Share Posted January 22, 2009 .....worth it since I can now tune my own car. Also, if you want to bypass the Theftlock, jumper Pin 55 to Pin 17 on the ECU harness. Aaaahhhh, tuning! I haven't figured out if I will keep or kill Theftlock, but I very much appreciate the insight.. Update: I have a friend who is the fire chief of a local town. Long story short, when they need a vehicle to practice on (emergency extraction, Jaws of Life, etc) they have a wrecking yard drop off several and spend the next month hacking them into smaller and smaller pieces. A week ago, a 98 or 99 Lumina appeared! He is already pulling the harness and computer...if I could only figure out how to have them get a 5 spd W to practice on next.... Quote Link to comment Share on other sites More sharing options...
Olds W31 Posted February 7, 2009 Author Report Share Posted February 7, 2009 Slowly but surely.... Ok, the 99 Montana has the big (20?)pin connector on the trans...the 98 Lumina is a MUCH smaller ((maybe 6-8) sorry it was dark) connector. I am not sure if I can add the wiring to the 98 lumina harness AND get its computer to work....Anybody ever try that? I noticed while we were pulling the harness that the Lumina had the Vacuum Modulator/Pressure thing. I can't believe GM would go to all the trouble and put in OBD 2 and NOT go full electronic on the trans....Genius! Maybe that is why GM is where it is today.... Quote Link to comment Share on other sites More sharing options...
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