1994 to 1995 Harness Discrepancies

[meissen]

So far, here are the discrepancies in wiring that we've come across on the engine harness. I'll update as we learn of any more.


C100:

• Pin D:
  • 1994 -> Traction control Active {Light Blue}
  • 1995 -> Power feed wire from PCM fuse #8 [interior fuse block] {Orange}

C105:

• Pin B:
  • 1994 -> Missing
  • 1995 -> Power Feed from Injector Fuse #10 {Pink}
• Pin E:
  • 1994 -> Missing
  • 1995 -> Serial Data Signal {Tan}

C210:

• Pin C:
  • 1994 -> PCM Power Feed from I/P Fuse {Orange}
  • 1995 -> Missing

C220:

• Pin D:
  • 1994 -> Spark Retard Request {Orange/Black}
  • 1995 -> Missing
• Pin E:
  • 1994 -> Throttle Position Sensor (EBTCM / ABS) {Tan/Black}
  • 1995 -> Missing

C230:

• Pin J:
  • 1994-1995 v6 ONLY -> Missing
  • 1994-1995 v8 ONLY -> Park/Neutral Feed from Transmission Position Sensor {Orange/Black}

[Bad_Z28]

Wow, you've got your hands full there, good luck getting in all straightened out!

[zdav28]

95 LT1 to 94 LT1

Meissen,
Did you get you car running? I have a 94 z28 that I bought for my daughter ($100) 60k, it's clean. It was a project I bought from some kids mom. I got everything ( in boxes), including a 383 scat crank, and rods. just didn't have a trans. so I bought a 95 from a police auction, pulled the motor/trans/pcm and dropped it into the 94. got everything hooked up, but it won't start. Cranks but no spark. looking at the connectors, it looks like I'm running into the same issue as you. If you did how did you rewire the thing. Or should I find a 94 pcm, and hook up the 94 engine harness??????? THanks for any help or advise.

[prorac1]

For what its worth, I have run a 95 pcm in my 94 before with no problem. Eric L

[meissen]

Meissen,
Did you get you car running? I have a 94 z28 that I bought for my daughter ($100) 60k, it's clean. It was a project I bought from some kids mom. I got everything ( in boxes), including a 383 scat crank, and rods. just didn't have a trans. so I bought a 95 from a police auction, pulled the motor/trans/pcm and dropped it into the 94. got everything hooked up, but it won't start. Cranks but no spark. looking at the connectors, it looks like I'm running into the same issue as you. If you did how did you rewire the thing. Or should I find a 94 pcm, and hook up the 94 engine harness??????? THanks for any help or advise.

Are you using the 1995 engine harness or the 1994 engine harness? The 1994 and 1995 engine harnesses are wired slightly differently (as shown in the first post), though once they get to the PCM they're the same.

If you're using 1995 engine harness, you'll notice that you have two plugs on the engine harness at the passenger strut tower but only one plug on the 1994 "engine bay" harness. The reason you're not getting spark is because that extra plug on the 1995 engine harness includes wiring for power to the injectors.

What you will want to do is find the pink power wire that's on the 1994 "engine bay" harness plug on the passenger shock tower - that's power feed for the injectors. You'll want to splice into that and then wire it to the pink wire on the 1995 engine harness male plug.

For what its worth, I have run a 95 pcm in my 94 before with no problem. Eric L

Eric's right - the 1994 PCM and the 1995 PCM is wired identically. I just went through this routine yesterday trying to help a guy on Ls1Tech... I found the wiring PDFs on ChiltonLibrary and for some reason they had 1993-1994 and then 1995 then 1996-1997. So I thought - Gee, 1994 must be different than 1995. Sat down with excel and mapped every pin for all 4 PCM plugs using Chilton's PDFs and then compared to Shbox's pinout for a 1995... Identical. Spent a good hour doing that exercise just to find out they're pinned the same.

[98blackbeauty]

we did have to spice into those plugs on the engine bay. Was the 94 a lt1 or v6. and is the 95 a lt1 or a v6
We did discover the engine bay harness had some differences from 94 to 95. don't confuse the engine harness with engine bay harness.
The engine bay harness wires go from fuse box to the connectors on the fender well.

[zdav28]

Both cars are z28, actually if you put them side by side you can't tell the difference, both metalic green, tinted windows, etc... Difference is the interior, the 95 is thrashed, the 94 has 60k, all leather, really nice and clean.

I pulled the 95 LT1 with trans and harness and dropped into the 94. The engine bay harness is the 94, the engine/trans/pcm/harness are all from the 95.

What you will want to do is find the pink power wire that's on the 1994 "engine bay" harness plug on the passenger shock tower - that's power feed for the injectors. You'll want to splice into that and then wire it to the pink wire on the 1995 engine harness male plug.

I'll try this this weekend, Thanks guys.

[Phantom409]

Here is a pg from EFI Connection showing the pin-outs.
These are for converting the LT-1 and getting rid of the Opti so you can use the LS computer but it should help ya.
http://www.eficonnection.com/coilper...s_LS1_Blue.jpg
http://www.eficonnection.com/coilper...ns_LS1_Red.jpg

[zdav28]

Both Cars are LT1's both cars had/have the optispark. The 95 has an extra engine compartment connector, c105. Which has a pink wire, power feed injector fuse #10 7.5 amp, and a tan wire, routes back to the drivers side firewall, serial data signal. What ever the heck this is for. I was tinkering with the idea of pulling the 95 engine harness off and installing the 94 harness. I did find it in one of the many boxes of stuff I got with the car. But just spicing a wire seems way to easy.

[meissen]

The serial data wire is what you need to use the diagnostic port if you ever want to pull codes or tune it. Personally, I ran my own dedicated wire from the PCM to the diagnostic port via the passenger side grommet in the firewall beneath the PCM.

[Phantom409]

Is there a problem with the 95 harness?
If not, PM me on what you would want for it as long as it's not damaged

[meissen]

...SHIT! Damn good idea there, Kyle..

[Phantom409]

That is why I'm the Dr.

[M_Juntti]

this makes me glad that when i bought my harness i bought every damn wire in the car lol

[Phantom409]

I need it for a project