PCM interchange for L67 top swap

[94GrandPrix]

Okay here's the deal

 

I've got a complete engine harness and PCM from a 96 Regal with the 3800 series 2. I plan on using this setup during my 3100 to 3800 swap with an L67 top swap thrown in. I also have the 4t60e from that same car so the gear ratio in the PCM is correct, and i'm not swapping in a 4t65-e just yet, that comes later. This setup is temporary, as in the future i'm swapping in the 65e with a 98-99 Z34 PCM and harness. This is just my experimental phase. Anyways, as far as the PCM tune is concerned, what recommendations does anybody have as far as if I can use this PCM or would I have to use another one? What's a good source (i.e, zzp, milzymotorsports, etc.) to send it to get tuned to run an L67 top end? The car getting the swap is a 96 Regal that has a blown 3100. I'm assuming that the wire harness connector on the firewall is identical to the 3800 powered one?

[Imp558]

16227797 is what I used. I started with a 1996 Regal harness, added the 4T65, changed the MAP plug and re-located it, added the boost and moved the Evap crap to the driver's fender so it wouldn't ugly up my pretty pretty L67.

 

Honestly if you can startout 4T65 it's not that bad to wire and all you really need is the tulip portion from the W-Body HD CV shafts. Making a 4T60 work with the PCM is always glitchy.

 

If a member with a tuning tool is within striking distance have them tune it or if you can do the 4T65 swap it'll run right now since both cars had passkey II.

[Imp558]

BTW here's the P/N's for the MAP sensor, the plugs come from Mouser Electronics for cheap just search these numbers on the site. Need 3 pins and 3 seals of course.

 

L67 MAP:

  Plug: 12041332-B

  Pins: 12089040-L

  Seals: 15324985

 

If I remember correctly that harness had EV1 FI plugs, just in case here they are for cheap too:

 

EV1 Injector Plugs:

  Plug: 12129142

  Pins: 12103360

Edited December 22, 2017 by Imp558

[94GrandPrix]

16227797 is what I used. I started with a 1996 Regal harness, added the 4T65, changed the MAP plug and re-located it, added the boost and moved the Evap crap to the driver's fender so it wouldn't ugly up my pretty pretty L67.

 

Honestly if you can startout 4T65 it's not that bad to wire and all you really need is the tulip portion from the W-Body HD CV shafts. Making a 4T60 work with the PCM is always glitchy.

 

If a member with a tuning tool is within striking distance have them tune it or if you can do the 4T65 swap it'll run right now since both cars had passkey II.

 

What do you do to add the 65e? Do you just wire it in place of the 60e's connector? Right now i'm wanting to use this 60e for experimentation purposes. So there's no way that the 3800 regal's PCM can be retuned to run the top swap while also running the stock transmission?

[94GrandPrix]

or if you can do the 4T65 swap it'll run right now since both cars had passkey II.

 

Your saying if I had a 65e and added the plug on the stock harness, the pcm will run it as is? No tuning? I thought the 65e and the 60e had different electronics internally. I guess shift points would be about the same, but other than that you know the 65e had a PCS line control strategy vs the vacuum modulated 60e.

[Imp558]

I didn't have a calibration file for the 1996 PCM but I did have a 7797 from a 1997 GP. The 1997 GP was unavailable with a 4T60 so it had a 4T65 in the PCM. They can be changed to do a 4T60 as the Regal PCM could likely be changed to do an L67. It's just way easier to use a combination that works out of the box.

 

 

You just remove the plug and wires from pretty much any GM harness and then follow the schematics one wire at a time.

If the schematic shows a wire from the Blue PCM plug on pin #2 that goes to the tranny plug on pin D then just do it. There's only like 13 wires to suffer through. You can solder the couple that are shared together and have a 4T65 plug hang next to a 4T60 plug - I've done it.

[94GrandPrix]

I didn't have a calibration file for the 1996 PCM but I did have a 7797 from a 1997 GP. The 1997 GP was unavailable with a 4T60 so it had a 4T65 in the PCM. They can be changed to do a 4T60 as the Regal PCM could likely be changed to do an L67. It's just way easier to use a combination that works out of the box.

 

You just remove the plug and wires from pretty much any GM harness and then follow the schematics one wire at a time.

If the schematic shows a wire from the Blue PCM plug on pin #2 that goes to the tranny plug on pin D then just do it. There's only like 13 wires to suffer through. You can solder the couple that are shared together and have a 4T65 plug hang next to a 4T60 plug - I've done it.

 

 

I agree with you, I figured it was easier to just go ahead and swap the tranny at the same time, so I reckon that's what i'll do and just do a full L67/65e swap. Doesn't hurt to pick the brains of more knowledgeable people though lol.

 

I think I get it know, so your saying literally ADD the wire into the harness from the new PCM to the trans. I can turn a wrench, but i'm still getting my feet wet with wiring.

[Imp558]

All you have to do is rip apart another harness and lift all the wires from the 4XXX series plug out. It doesn't even technically have to be a W-Body, it can be any GM car with a PCM that physically looks like yours (same pins on the wires) then just make those wires go to and from the right spots.

When you're ready post and I or someone else will get schematics and pinouts up. You could do it in your car's build thread if you want.

Remember you need those HD CV tulips though, the HD has a different spline. An HD from a non-W should have tulips that are the right spline for an HD but too big for the tripods on your CV shafts.

Aside from the CV shafts the HD falls right in, after you run those dozen wires or so.

[l67ss]

Actually a 97 gp GT came with a 4t60....

[Imp558]

The GTP had a 65 and L67.

[l67ss]

Yup

[94GrandPrix]

When I go on carpart, it says you can basically use any second gen pcm from at least 96 to 200x. So, if I wanted more tuneability with a stock 96 regal 3800 pcm could i use a 97 gp gt pcm? Would that just plug into my stock harness? Im assuming I would need to rewire a few things at the pcm connector?

[Imp558]

Be careful, another PCM will work but they don't all have the same pinouts. The '7797 is pinned the same as the 96 Regal harness aside from having to add those items I said yesterday.

[94GrandPrix]

PCM 7797 is for a GTP right? So this pcm is programmed for L67 and 4T65e. Adding the 65e plug into the regal harness to the new pcm and all will be good? How much on the firewall connector did you mod? I'm assuming none? From 3100 to 3800 the connectors looked identical on the pinout i have for both engines.

[Imp558]

I think C100 is okay. 7797 comes out of a bunch of cars, Ideally you would want a W-Body with a 4T65-E HD/L67.