Converting to OBD 1. Have computer/harness, now what?

[blackbombshell95]

I'm converting my 95 obd 1.5 to pre 94 obd 1.
I am going by brads guide here.

http://60degreev6.com/SwapGuides/PCM%20Downgrade%20for%20Performance%20Upgrade%20Swap.doc

I managed to pick up a computer with the wiring harness attached. I cut it about 18 inches down so i have 18 inches of wire to play with. I got it from a grand prix with the 3.1.

Let?s first cover the basics. This document is being written to allow a GM 16149396 ECM to take the place of a GM 16156397 PCM. The 16149396 ECM was used in 3.4 DOHC equipped cars in the early to mid-90s. They are identical to the 7727/7730 ECM

I got the 7727 one.

my quick question is, now what do i need now from this quoted parts list. If at all possible just quote the part of my quote that I need. Very simple. Thanks. So i have the computer with the plugs attached with 18'' of wire on it.

 16149396 ECM: You can usually one of these floating around eBay for around $30. If not, head to a junkyard to pick one up. They are found in cars with a 3.4 DOHC, and also 93 Grand Prix?s with the 3.1L.
 16149396 Harness Plugs: Most eBay ECM auctions don?t include the harnesses, so you?ll have to go to a junkyard and pick these up. Some yards won?t let you just take the connectors, so you might have to do some searching or just get the entire harness. If you can just get the plugs, get ~24? of wiring to get with the plugs.
 16156397 Harness Plugs: These are available from GM Parts Direct for ~$112 (plus S&H). You will need all of the following parts:
o 12129025 (x3) : $4.26 each
o 12129021 : $0.97 each
o 12129022 : $0.97 each
o 12129023 : $0.97 each
o 12129028 (x3) : $2.13 each
o 12084913 (x ~75) : $1.20 each, come in packs of 5 ($6.00/pack)
 16156397 PCM Plugs: These are the actual PCM connectors that are mounted to the circuit board inside the PCM. You can get these from the Power and Signal Group, and most likely for free! They are a large-quantity supplier, but do send out free samples of products to see if they will meet the customer?s needs. Do a search for these part numbers and then just add them to your Sample Cart. Once you are done, just follow the remaining steps to get them sent to you for free!
o 12129008 , 12186041 , 12186043
 16 gauge wire: You can get this just about anywhere, but electronic supply stores (such as Radio Shack) are your best bet. You don?t need more than 1 color, but several colors will make wire identification slightly easier.

[bszopi]

RE: Converting to OBD 1. Have computer/harness, now what?

Well, first of all, there was a reason I said you need to get the 9396 ECM. The 7727 doesn't have the extra RAM to be able to control the 4T60E tranny... I think I even mention that in that guide. So, as far as the parts needed in that list, I'd go with all of them, including the ECM. You can probably keep the harness and just repin the connectors as needed.

[blackbombshell95]

RE: Converting to OBD 1. Have computer/harness, now what?

luckly i have 30 days to return the computer to the junk yard. So i will look for the 9396 one. Thanks.



"The 16149396 ECM was used in the 3.4 DOHC equipped cars in the early to mid-90s. They are identical to the 7727/7730 ECM (widely hacked GM ECM found in virtually all makes of models of GM vehicles in the 80s and 90), but include an additional 256k of RAM for electronic transmission control (mainly, the 4T60-E)"

so to make my 4T60-E work i must use a ECM from a DOHC. So the 7727/7730 from a 3.1 won't work.


If the engine is out of the car with a chair in the engine bay, how long do you think it might take an experienced person to sit in the engine bay and perform this task. I am going to pay a friend to do this for me.

I'm going to order the parts from the list now.

[bszopi]

RE: Converting to OBD 1. Have computer/harness, now what?

I'm an experienced solderer, and I did it out of the car and it took me almost a week to do the harness. With the info I supplied, you are looking at making effectively 2 harnesses, and with ~70+ pins per harness, thats pretty close to 150 small solder joints. One half of the harness is composed of connectors that are normally soldered onto a PCB. So, ensuring that none of the wires or connections touch is critical and can be a very tedious process for even an experienced solderer.

[blackbombshell95]

RE: Converting to OBD 1. Have computer/harness, now what?

a week. wow. u know the total was like $157 shipped. and 112 for the parts lol.

Hey i went to that site to try and attempt to get those 3 items for free. And it set me up to email them. So i wonder if they will just email me back and ship the stuff?