My '90 TII wiring is CRUSTY! Wiring Harness ???'s
 

The engine bay wiring is getting very BRITTLE and needs to be replaced. Now, I've searched for "Wiring Harness" but this only prompted more questions from me, so here goes...

From what I gather, there are 3 Harnesses: (1) Main, (2) Engine & (3) Alternator/Starter. The wiring that is the worst is the located in the engine bay, on the Passenger-side. I think the O2 Sensor goes into this cluster of wires.

(A) Which Wiring Harness is this?

(B) Where is the best (read: cheapest) place to get a >new< Wiring Harness? (When I finally find out which harness I need, of course)

(C) How difficult is it to install a Wiring Harness?

(D) Is it just "Plug 'n Play" or do I have to remove other parts (it's kinda tight in there) and reset things...

(E) Are there any other Wiring Harnesses, besides the three mentioned above, that I should check, and where are they located?

I know I'm full of questions, but I'm willing to learn. Just explain it to me like you would a 4-year old :D ... or like a retarded cousin or something :p:

Re: My '90 TII wiring is CRUSTY! Wiring Harness ???'s
 

A) I think that is considered part of the engine wiring harness.

B) Only place I know of, if you can still get it, is the Dealership. They might not make them. I know they do for the 89+, or atleast you can still get them, but not to sure of the 86-88. The are expensive from the dealership. Approx. 400-500, maybe a bit more.

C) Not very, but to do the engine harness you gotta pull the intake manifold since it runs under it.

D) See answer to C. beyond that, all you do is unplug the old wires, remember which connector went where, and plug in the new connector.

E) The rest should be good.

your in for a nightmare buddy

OK - how so?

Have you done this before already? If so, how about sharing your experience with the forum.

And thanks for the... uh... sympathy?

it depends which harnes you r talking about .....but if its the eng harness and its crusty because of your turbo .......you will need to take the manifold off .......make sure you label everything.......and VERY IMPORTANT take a pic of how the harness is routed ...........note that last one i did i repaired the harness .....it takes TIME ,AND LOTS OF PATIENCE to remove any crusty wire solder it and install heat shrink .....just something to keep in mind if you cannot find a harness or you are unwilling to pay the 1500.00 the dealership wants for it

You can get a harness for much cheaper than $1500. Try calling some wrecking yards, different dealerships, www.thepartstrader.com.

Count on your car being down for a weekend and like VMB said, label everything and take pictures. Do a silicon vacuum hose job at the same time.

the only problem with buying is that you may be buying someone elses crusty burnt no good harness .....unless you buy it from a local junkyard .....i would try to repair it !!!!..........just my 2 cents

I agree, repairing the nasty parts of the harness requires a soldering iron, solder and the correct gauge of wire.

Perhaps an investment of $20 TOPS.

A buddy of mine got a brand new harness from the dealer for $450..that's with a discount that some of us get.

$1500 dealership USD?????
I paid $800 CANADIAN, with taxes for my engine harness. That just an estimated price, or what, b/c I can't see there being that much of a difference.
Easy to do, as well, took me about 3 hours to remove the old one and put in the new one, going quite slowly.
For $1500, get a haltech!
Sean Cathcart

the engine harnesses are about $400-500us the $1500 one does the whole car. if you want to fix your try paul @ www.k2rd.com he can get a lot of the connectors

mike

I think I'll take a closer look at exactly how much of my harness is f'd up. If it's not >that< bad, then maybe I'll go the solder and heatshrink route.

I got practice today wiring when I put my door and rear speakers in. But I capped the wires instead of soldering, hehe... lazy. :p:

And I know it's going to be a lot more tedious messing with the wiring harness than just splicing in + and - wires to my speakers ;)

Or maybe I'll go wrecker yard shopping... but I'll have to find an '89-'92 TII Harness, not just any harness off an Rx-7, right?

It guessing it may prove difficult finding a TII that isn't already picked over.

We have some leftover sil. insulated wire at my work from a Gov. job. When I put in the Haltec I am going to use that; that stuff would probably survive an engine fire- I played w/ it in a propane torch and it just discolored it :)

go haltech ;) just kidding

You may be kidding, but I'm not :)

If you're going to go to the trouble, you might as well. That'll also allow you numerous tuning capabilities, and completely open up your future upgrade path. If you can get in on a Haltech group buy, you can get "the works" for ~$1300. And let's be honest, if you can afford to replace your wiring harness "just because", a Haltech isn't gonna scare you :)

Brandon

Mazdatrix does sell the engine harness for about $580. I bought one a few months back. Yes, it's pricey, but the last thing you need to do is start hacking, cuttin, and patching the 12 year old harness and find out one night on the way home that you have yet another short or something. I found not only the wires very brittle above the turbo, but many of the connectors disintegrating as well.

If you want to do it affordably, try a used one-- but expect that it may not be any better than what you have now.

If you want reliability, replace with a new one.

$580 USD???? from mazda trix? Thats crazy!
Its only $500 from the dealership (on an 90 TII engine harness), including taxes.
Sean Cathcart

I have questions about the wire harness too. This is for a 87na. Right now I have the upper intake completely off.

The wire harness I might need to replace comes through the firewall on the passenger side .... Goes over the front of the engine to the drivers side .... Curls around towards the back of the engine under the upper manifold ... its the harness that connects to the injectors among other things.

The part of the harness that is in the engine bay looks easy enough to replace. I'm concerned about the part that goes through the firewall ... Where does that part of the harness lead to inside the car? Does it run right to the ECU? What parts do I need to solder? What else do I need to know....

George

btw I do have a spare one that looks like it is in ok condition

that harness pugs into the ecu and the are 2 connectors tha plug into the dash harness that you might have to remove the blower motor to get at, its not hard to do at all though

mike

nope. You just need to pull back the carpet and unplug the connectors. You don't need to remove any interior parts, save the door scuffguards. Then push/ pull the harness out, making sure you don't have anything else connected. I had two connectors up on the passenger side. You need tiny girl hands like mine to get them off.
Sean Cathcart