PCM / Harness Question
 

Hey guys,

I have a 95 Z which I am having an issue after a trans swap. Was originally a 6 speed car, which I converted to a 4L60E. I purchased a used engine / trans Harness which was from a 97 and installed it with the new trans.

The 97 Harness should work, with the exception of the coil and knock module , which I have changed out to work with the 97 harness. Also I bypassed the clutch safety switch. The PCM is still set for the M6.

Everything is in, the car turns over , but will not start. I tried to run Datamaster and It cannot communicate with the PCM. Tunercat also cannot make contact with the PCM.

Anyone know why this would be happening. Everything is hooked up fine and where it should be with the new harness.

I guess its possible that the 97 harness is bad , or do some Pins need to be moved around?

Thanks.

i would go back to the 95 harness and pinn the pcm i did a 95 swap and it was very simple

You will need to re-pin the Harness to the 1995 setup, the major one at the moment being the Serial Data Wire. That is the wire that the PCM used to communicate to whatever you hook up to it through the DLC.

Thanks for the replies. Do you think its easier to re pin or just get a 95 A4 harness and sell the 97 one?

Get a 1995 one.

Do you mean knock sensor? I believe the knock module is generic for all OBDI/II years (with the exception of '93 of course), however you need an OBDII knock sensor to be compatible with an OBDII PCM.
Have you checked to see if your data port has voltage? Get a schematic and a volt meter and start chasing wires. Is the DataMaster and Tunercat for the OBDII PCM?
You can also have the PCM reflashed by Ion for an auto which would probably be a good idea.

Can't really do anything with it at the moment if the Wires aren't in the right spot communicating with everything.

"Do you mean knock sensor? I believe the knock module is generic for all OBDI/II years (with the exception of '93 of course), however you need an OBDII knock sensor to be compatible with an OBDII PCM.
Have you checked to see if your data port has voltage? Get a schematic and a volt meter and start chasing wires. Is the DataMaster and Tunercat for the OBDII PCM?
You can also have the PCM reflashed by Ion for an auto which would probably be a good idea"


Yea, I meant knock sensor. The PCM is still OBDI , but the harness is OBDII. I can reflash the PCM to the auto, but obviously need to make a connection first.My tuning software is OBDI.

I may just try to find a 95 harness ,swap that back, and sell the 97 one.

thanks

Not completely sure, but I think the wiring configuration for the data ports between the OBDI and OBDII are different...

A PCM alone could be sent to Ion to have it re-flashed w/out the harness.

The only 2 pins you need to do programming/scanning are 5 and 9 (on the 16 pin DLC) with the OBD-I computer. Those two wires go to the same places whether it is OBD-I or II, so the wiring should already be there.

Yea his wiring should be there since he has a 1995 model. Pin 2 is actually wired over to the Dash Connectors aswell, that is what the LS Engines use.

True, but I would rather look into the car and un-fuck the problem of it not communicating with the PCM first.

Doing some checking at the A through D connections at the PCM, I dont have any ign or Bat power going to D3, B30 or B31.

Also nothing at the serial data D30.

Could this be due to the difference at the C100 connection between the 95 -97 models? the 95 C100 has a PCM power feed which is not on the 96-97 harness. C210 and C230 also have conflicting or different PCM power feeds.

Thanks again for all the replies. just trying to get this sorted out.

Yes, there are some subtle differences. You'll need to match up the power feeds.

There are two power feeds differences that will have to be relocated:

'95
C100 D power feed from PCM fuse #8 to PCM
C230 G power feed from PCM ignition fuse #5

'97
C210 C power feed from PCM BAT fuse to PCM
C220 E power feed from PCM ignition fuse #13
C230 G power feed from engine sensor fuse #10

You need to match up the PCM fuse to PCM wires and the PCM ignition fuse wires.
One other thing is that I don't know what needs to be done with the power feed from engine sensor fuse #10 ('97 C230 G).

EDIT: updated after shbox's answer to a question.

C100 K is for V6 VIN S as noted on my site.

Gotcha. I updated my first post. So the only thing left is where the power feed from the engine sensor fuse should go...if needed.

On the 1995 Car I would stick that in C-100 Pin E(I beleive this one is it, it should be a brown wire). It comes from the Fuse #6 which is the Fans/ACTR Fuse. If that's not it then get a test light till you find out which one is hot with that Fuse, one of the Wires gets power from it.

i have a comlete 95 harness that will plug right in for 200

I have the appropriate harness on the way to save any additional headache. I not really up for splicing and chasing at this point. I just want to finish the car up.

Thanks to all who replied trying to help me out.

I understand. But for future reference, you don't have to splice anything. All you have to do is use a paper clip to depress the retaining tab on the individual pin and it will slip right out. Then you can relocate it to the correct cavity of the new plug. Very simple.