96 LT1 Swap into 94 Z28. Can I use OBDII PCM?

**FastLT1** · 02-05-2017, 11:29 PM

Hopefully next weekend I'll be pulling the built LT1 out of my long term 1996 Z28 project so I can drop it into my new 1994 Z28. Both Z28s are complete, running 4L60E cars. Reason for swapping is that the body on the 96 is junk and needs to be scrapped.

From everything I've been reading, all I have to do to run the 96 engine in the 94 body, is swapping in the OBDI knock sensor and using the older 94 style ignition coil since the connectors are different.

I originally planned on doing that (if that's correct and all I'll need to do) to stay with the OBDI setup. But I've been wondering, would it be possible to just plug in the 96 OBDII PCM into the the 94 harness and use that? The reason I ask is because I've already had Solomon tune my 96 PCM (that I still haven't used as the 96 isn't drivable currently) and I have some 30lb injectors that he tuned it for.

But if I stay with the OBDI PCM, I'll have to send it off again to be tuned for everything like I did the other PCM. I know the 96 has a crankshaft position sensor that older LT1s don't have but I've read that it can be left unplugged with no affects since the OBDI PCM won't be looking for that

**blown383ta** · 02-12-2017, 06:09 PM

Just use your 96 harness and pcm. There's very little difference between body harness'. Just pull up the wiring diagram for both and you might need to move some pins around at the connector on strut tower, or the stands that go inside the vehicle behind computer. I did this with my 94 into 93 body.

**SSlowBoat** · 02-12-2017, 07:08 PM

Originally Posted by FastLT1

Hopefully next weekend I'll be pulling the built LT1 out of my long term 1996 Z28 project so I can drop it into my new 1994 Z28. Both Z28s are complete, running 4L60E cars. Reason for swapping is that the body on the 96 is junk and needs to be scrapped.

From everything I've been reading, all I have to do to run the 96 engine in the 94 body, is swapping in the OBDI knock sensor and using the older 94 style ignition coil since the connectors are different.

I originally planned on doing that (if that's correct and all I'll need to do) to stay with the OBDI setup. But I've been wondering, would it be possible to just plug in the 96 OBDII PCM into the the 94 harness and use that? The reason I ask is because I've already had Solomon tune my 96 PCM (that I still haven't used as the 96 isn't drivable currently) and I have some 30lb injectors that he tuned it for.

But if I stay with the OBDI PCM, I'll have to send it off again to be tuned for everything like I did the other PCM. I know the 96 has a crankshaft position sensor that older LT1s don't have but I've read that it can be left unplugged with no affects since the OBDI PCM won't be looking for that

Use the 94 harness and have someone else tune it. Please. Also swap a 94 front pump in the trans and valve body. Otherwise ur trans isn't gonna survive because the 96 pwm trans IS different shifting internally than the 94.

Or swap the entire engine/body/dash harness along with modules over

Sent from my iPhone using Tapatalk Pro

**Injuneer** · 02-12-2017, 10:16 PM

Shoebox has the body connector pinouts for each year:

http://shbox.com/1/harness_connector_faces.htm

Note tabs at bottom for each connector.

**blown383ta** · 02-13-2017, 06:52 AM

Good point tubby, forgot about the pwm, but that's only for lockup, and can be altered by blocking the tcc control valve in the valve body, which will make it on/off just like the 94. Everything else is the same function wise. Just need to double check pin outs@trans to verify none of the other circuits have been relocated, but I'm pretty sure the added solenoid used previously empty cavities

**SSlowBoat** · 02-13-2017, 07:13 AM

Originally Posted by blown383ta

Good point tubby, forgot about the pwm, but that's only for lockup, and can be altered by blocking the tcc control valve in the valve body, which will make it on/off just like the 94. Everything else is the same function wise. Just need to double check pin outs@trans to verify none of the other circuits have been relocated, but I'm pretty sure the added solenoid used previously empty cavities

No, the valve body down shift sequence is different. Using a 96 trans on a 94 PCM will make the downshift a 3 neutral 2 or 2 neutral 1 downshift. I can show you a video of my impala before I had Frank change the valve body and he yelled at me for doing it, VIOLENT down shifts, which are bad for trans, @Cahall can elaborate

Sent from my SAMSUNG-SM-G935A using Tapatalk

**Injuneer** · 02-13-2017, 10:31 AM

Originally Posted by blown383ta

Good point tubby, forgot about the pwm, but that's only for lockup, and can be altered by blocking the tcc control valve in the valve body, which will make it on/off just like the 94. Everything else is the same function wise. Just need to double check pin outs@trans to verify none of the other circuits have been relocated, but I'm pretty sure the added solenoid used previously empty cavities

Have you seen this?

http://ltxtech.com/forums/showthread...d-interchanges

**CPT** · 02-13-2017, 10:38 AM

The ONLY way to swap 4L60Es between a '94 and a '96 is to swap the complete valve body, internal harness, and front pump. Any attempt to try to "modify" any of these parts to work with the wrong year PCM WILL result in transmission failure.

Frank

**FastLT1** · 02-13-2017, 10:43 AM

Originally Posted by Cahall

The ONLY way to swap 4L60Es between a '94 and a '96 is to swap the complete valve body, internal harness, and front pump. Any attempt to try to "modify" any of these parts to work with the wrong year PCM WILL result in transmission failure.

Frank

Wow I didn't know that. I thought you just had to run a new wire to the 94 PCM for the 96 TCC or whatever it was that I read. In your opinion, if I were to send one of these transmissions to you to be built, would you recommend just having the 94 built or having the 96 with swapped parts built?

**FastLT1** · 02-13-2017, 10:45 AM

Originally Posted by Tubby Z28

Use the 94 harness and have someone else tune it. Please. Also swap a 94 front pump in the trans and valve body. Otherwise ur trans isn't gonna survive because the 96 pwm trans IS different shifting internally than the 94.

Or swap the entire engine/body/dash harness along with modules over

Sent from my iPhone using Tapatalk Pro

@Tubby Z28, I sent you a PM. I'm not sure if you received it or not because for some reason, my inbox doesn't show new sent messages anymore so I can't see what I sent you lol