93 to 94-95 PCM and Harness??

[SpeedDensityZ]

Okay, When I got the car on the dyno I found out that I am having computer problems. I was told to check my harness for breaks or shorts. Well, after further inspecting my harness it is spliced in way more than originally thought. I knew the oil sensor was spliced and the coolant sensor but,OMG every fuel injector harness is but connected together. After all the work I've done to the car I never noticed this. I've also had the CPU replaced once before. I'm having Quad Drive failures. My question is. What do I need to switch to a 94-95 PCM.

Parts I know I need:
94-95 PCM
Engine Wiring Harness
IAC

Do I need anything else?? I figured if I have to change a CPU and a harness, I should go to a more common and easier to tune setup. I need to get this resolved fast!!!

-Thanks, Justin

[FastVert]

Good luck finding an unmolested harness.

I do have a 95 PCM - I wasn't planning on selling it but I really don't have a need for it anymore. 75.00 +SH if you are interested.

[meissen]

With switching from a 1993 to a 1994-1995 harness, you're going to have some wiring differences that you'll need to address.

I would recommend getting a engine harness and PCM from the same year - 1994 or 1995. It might be slightly easier to get a 1994 because it's still OBD1. 1995 was OBD1.5 and since I just did a 1994 to 1995 swap, I can tell you there's a few differences between '94 and '95... going from '93 to '95 might be a little harder.

When it comes to the actual wiring, keep in mind the 2 locations where the engine harness ties into the engine bay harness and the interior dash harness.

Your engine harness will tie into the engine bay harness on the right shock tower. In 1993 and 1994 there was only one plug. In 1995+ there's two plugs. Looking at the wiring for 1993 to 1994 for the one plug, I can tell you right off the bat that the plugs are not wired the same and you'll have to do a few wire rearrangements.

Your engine harness will tie into the interior dash harness on the inside of the passenger kick panel area by the firewall. 3 plugs are present. You'll have one 4 wire plug and two 10 wire plugs. I just took a quick glance at the 4 wire plug and I can tell you that in 1993 only two wires were used. In 1994, they added the PCM battery power from the interior fuse box AND the feed for the fuel pump through that 4 wire plug.

You can change the wiring, but you'll have to deal with these differences between the years. Most are pretty easy changes, some can be a little complicated tracking down where the source wire is to tie it into the engine harness where it wants it. But, if you get a Chiltons manual for 1993 and the year of the engine harness & PCM you buy, you can logically go through the PCM wiring harness one pin at a time and find out where each wire is coming from and then figure out how to get it to work.

I hope I wasn't too confusing on this - sometimes it's hard to explain. I would definitely recommend checking out Shbox's website, specifically this page: http://shbox.com/1/harness_connector_faces.htm which will tell you the pinouts of each connection that ties into the engine harness for each year 93-97.

[SpeedDensityZ]

Thanks for the insight. Doesn't seem too bad. That's exactly what I was looking for. Someone who had done it. Thanks. If I have any questions I'll pm you.

-Justin

[meissen]

Sounds good man - I try to check in here often but time is always against me. :) I know exactly how it feels to be trying to find this info and seems like ya can't find it in simple terms that lay it all out. I'm just glad to be able to help people now that I've been through it. :D