elisowski

I need a new engine harness for a 94 Camaro M6 that has been converted to a TH-350. I have converted to the 95 vented opti.

I have been told that the 94 A4 and the 95 A4 harnesses are not interchangeable do to changes made to the tranny between model years. So I don't think I can use a 95 A4 harness.

Can I use a 95, 96, or 97 M6 harness instead?

Injuneer

I'm not sure I understand why you need a new harness. The TH350 doesn't have any electronics except for the VSS. You will have to see if you can put the correct VSS on the TH350, or possibly change the VSS pigtail. You will have to match the PCM program to the number of teeth on the TH350 VSS reluctor, or use a Dakota Digital interface to convert the signal. The existing harness connections for the M6 (skip shift and reverse lockout) don't need to be connected to anything. Resistors will eliminate any codes for those two solenoids if you stay with an M6 program. And you only need to change the short Opti harness from the passenger side of the intake to the Opti to connect a vented Opti to a 94 harness.

LT4Camaro

u just dont use any electrical connections to the trans except the 1 speedo. shouldnt matter m6 or auto harness .

elisowski

I am having a problem with the ignition or injectors. Everything has been changed (plugs, wires, stock opti, MSD billet opti, pcm, coil, msd 6-AL swapped to Digital 6, map sensor, injectors, injectors swapped from side to side, etc.) I even borrowed a coil module and MAF from a friend.

It is a whole new engine combo. I had the same problem with the old engine, so I believe I have a problem in the harness causing an injector problem and/or ignition problem.

My vacuum gauge moves back and forth 2 psi at idle indicating a leaking valve or a mis-fire/injector fault. I have brand new heads that are different from the past combo. So I am somewhat confident the valves are ok. Only 1000 miles on hew combo.

I am having a hard time pulling above 5500 rpm in 3rd gear (3.1 seconds from 5500 to 5900 on a 11.87 sec run) and a really long dyno pull to get to 6500 rpm. Dyno results show I'm down about a 100 hp. The rpm does not climb steady (5500, 5650, 5575, 5700, 5650, 5725, etc.) It pulses up and down about 200 rpm.

The only thing the same between the two combos is the wiring harness. And I've had problems with broken wires to the coil module, map sensor and TPS. They're brittle.

So I believe I need an engine harness.

So I need to know if I can use a 95, 96, or 97 M6 harness for my 94?

PS - I have the VSS hooked up now through the front wheel sensor and the rear gears set to 2.85 in the pcm. My Rossler tranny has an A4 VSS machined into the tailshaft so I can use an A4 connector on it (not currently hooked up). I "THINK" I am ok on the tranny hook-ups, but not 100% sure.

Thanks

Injuneer

The problems with the wiring harness interchangeability occurs mainly at the body connector interfaces. There are differences in each year. All the engine control wiring is virtually the same between 94-97, although obviously with the 96/97 OBD-II harness, you will have a lot of unused connectors hanging loose. If you are willing to rewire the body connection interfaces, it will probably be all that is required.

Have you considered contacting an outfit like Painless to see if they can build you the correct 94 harness?

elisowski

I have a question concerning the body interfaces. I have seen pictures of people advertising engine harnesses for sale and I have looked at the Painless harness.
Here is a picture of a 95 M6 for sale now:
www.camaroz28.com/forums/showthread.php?t=575413&highlight=wiring+harness

I know you have 4 pcm connectors (red, blue, black, grey (?)) They're labled A,B,C and D in the service manual (no color reference). I'm hoping one of these goes inboard.

How does the PCM communicate through the ALDL connector for Datamaster and LT1 edit? Something must go inboard (I think).

But, it seems to me looking at the pcm pin diagrams, that some wires run inboard from each connector. Is this correct?

Also, looking at the picture in the link above, I don't see where this would run inboard. Can you see where it would run inboard or connect to the body interface?

On the second comment, I contacted Painless and they said that the one they offer (part #60502) is a stand-alone system for transplanting an LT1 into a non-LT1 car (retrofit). I downloaded the install guide and there are provisions to power the harness, power the fuel pump, and have an external ALDL connector with SES light. They also said that there are alot of unused pins in their 4 pcm connectors that they provide and that I could pull the old wires out of an existing harness and plug them into the connectors on their harness (if I wanted to), but that they do not have anything else.

I know there's alot of questions, but I need to know if there are other alternatives than just a 94 M6.

Thanks for your time.

Injuneer

Look at the connector diagrams on Shoebox's site, for an idea of what you are facing (note that there are "tabs" at the bottom of the screen for each connector):

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

elisowski

OK. Thanks for the link.

It appears to me that all of the pin assignments in the conncetors except C220 are the same.

I would have to add:
D) spark retard request
E) TPS signal

How hard is it to add these wires to an existing metri-pak connector?

Or, are there aftermarket connectors that would make it easier to replace the whole connector?

elisowski

How hard is it to add these wires to an existing metri-pak connector?

Or, are there aftermarket connectors that would make it easier to replace the whole connector?