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OBD2 conversion Rev.B - L27

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Old 04-20-2008, 04:00 PM
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Eh, I'm not going to chance it. I'll do what I can to make it fit under the dash.
Old 05-12-2008, 06:32 PM
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Found something that might make the conversion easier to accomplish cheaply. I did a search on "gm 32 pin" (what is used for the three PCM connections), and this is what I came up with...

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Granted there are some wires missing, but should be simple enough to put them in there. These connectors will allow me to construct a new PCM interface for the existing 94/95 PCM connections inside the cabin. And will be MUCH easier than trying to salvage the RWB connectors from a junk PCM.
Old 05-12-2008, 10:12 PM
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Originally Posted by sandrock
Found something that might make the conversion easier to accomplish cheaply. I did a search on "gm 32 pin" (what is used for the three PCM connections), and this is what I came up with...



Granted there are some wires missing, but should be simple enough to put them in there. These connectors will allow me to construct a new PCM interface for the existing 94/95 PCM connections inside the cabin. And will be MUCH easier than trying to salvage the RWB connectors from a junk PCM.
Isn't that the wire adapter so you can hook up a aftermarket stereo in the newer style GM cars. (I am not referring to the 00+ GM-bus one, before that).
Old 05-13-2008, 04:25 AM
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Yup, that be the one. Funny that they use the same shell the PCMs use

Wally World has a few of them...gonna pick up one just to verify that it is what it is. If it will work, I'll pick up two more. Also gonna need to write Scosche to see what wire pins they use and how to get them since I will need to add wires..or just buy 5 or 6 more harnesses and pull wires from them.
Old 05-16-2008, 01:27 AM
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Dude, you truly rule. If (when) I do the PCM swap, would I have any issues going with a 98+ PCM to avoid the size issue? Is the connector still the same? How about the transmission'* shift points? Disregarding the PCM size question, what do you think of using a 96 PCM setup to retain the 4T60 control rather than 4T65? And disregarding that question, do you think a 97+ PCM would make it easier to swap to a 4T65 transmission with a Series 1 L67?
Old 05-16-2008, 08:53 AM
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Rad, no offense bro, but if you can't even get the wiring right for turn signals, what makes you think you can accomplish something of this magnitude? I'm an electrical engineer/fabricator/avionics tech by trade, and it took me about 6 months start to finish on Rev A. AND I spent some heavy bucks doing it.

But to answer the questions...from my experience, a 1998+ pcm should be considered the "jack of all trades" in applications like this. 1996 and 1997 PCMs are identical in every way w/ exception of the OS. HP Tuners only support the 1997 OS, so unless someone has a DHP Tuner, the 1996 PCMs are out of the question.

Now then...connectors are the same for all the OBD2 PCMs mentioned thus far, but the pinouts changed for 1998. So there is no direct swap for a 96/97 vehicle to a 98+ PCM unless the whole wiring harness is changed.

And I ran a "modified" transmission table from a -65e to control the -60e. There were *some* issues in doing that that I never was able to get around to fixing, as that approach was completely experimental. I had to because the OS between supercharged and non-supercharged were different. OS determines pinouts, so in order to get boost control, I HAD to use the L67 file, which only had -65e tables.

As I said before in my other conversion post, this mod is NOT to be taken lightly. It is VERY easy to screw it up, and even easier to screw up the operating tables as there are no good existing tables in the tuner repository.
Old 05-17-2008, 12:34 AM
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Hey Sandrock. This is not a post hijack. I can do the turn signal wiring for my car, and it can work with an aftermarket switch and new wires (under a test setup as I'm still hoping to fix it the good way with my FSMs - they're in the mail). The problem I have is that the left turn signal is much slower and is shown as being on under WOT. That'* just ridiculous. I'd love to fix is as much as anyone else would if in my shoes, but I couldn't get through the firewall because of inspections people coming by and seeing if they should charge me money for not having an interior as I work on my wiring. Unfortunately, they still got me. I owe them $50. I need to see if I can now take apart the dash now that I'm going to pay the fine anyway.

I remember in your other post how you were talking about selling this idea. I'm all for buying it, so I don't want to develop it independently of you. Your results with allegedly better shifts and some tuning headroom make me want to do the PCM swap, and I'm excited about it. I'll see you at a SEBF with working turn signals and hopefully a PCM swap. The chrome toggle switches are going to have to be reassigned.
Old 05-17-2008, 06:42 AM
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Well, that being the case...

You still have to get the tuner from another source. The usual cost is around 500 dollars, plus the laptop if you don't have one. Technically, this is the only option to take as INTENSE or any other shop does not...and probably never will...have the numbers to make the S2 computers control S1 engines. That issue alone probably kills alot of potential in making this a DIY kit.

Harness-wise...it'* doable. I'm going to verify if those 32 pin connectors will work for this application this weekend. On top of that, I will have to verify which wires MUST be run independent of the main harness (like cruise control, 2nd O2 if it wants/needs be run, 2nd knock sensor, and anything else the S1 motor does not have), and where to run them through the firewall.

It may not happen at all now, due to an...addition...to the driveway I acquired last night. The SSE MUST go now, so the only to make it happen is to use Dons 95 as a test mule, which I don't think he would mind at all.
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