TalkSick

flame if u must but im a pretty thourough reader of th 2nd gen forums n i dont recall havin seen anything really of this nature (course it may have a less then descriptive title)

wondering what sort of undertaking it is to rewire the engine bay. Ive got an 87 NA and its startin to show electrical gremlins, among others. I absolutely love this damn car though, the thought of havin it die makes me want to follow suit so i will do as i must to proling its life. I have every intention of replacing the brakes, suspension, exhaust, intake etc etc, however its all kinda a waste of time if the bastarddont run due to shorts. so until i fix it and know its rock solid i cant justify the expenses n time invested. also seems a good opportunity to learn a lil more about the workings and locations of everything.

first off are there wiring harnesess commercially available? sort of premade like you would purchase for a car stereo install or something ( i know its a long shot but hey they sell everything else)

is there any sort of write up on the number of wires, lengths, connectors needed etc to do this?

any info would be helpful as at this point my best idea is to go to the junkers an go about removing all the wiring from a toasted rex an takin it home to use as a template to make a new one, id prefer to not have to do this though if i can avoid it for obvious reasons (im in canada its cold, and it seems like twice the work as i will have to remove the same from my car afterwards as well, id tear it out of my own car but then what will i drive to the shop to buy wires, connectors, painkillers, alcohol once i know what is required)

i understand there will be some serial pains in the *** as far as running the wires and connecting everything however it beats trying to troubleshoot **** for the next X years till i manage to kill myself driving it.

please as fellow RX lovers understand the desire i have to make this the sort of rex u make an example of scoffers with, its in damn good shape all things considered and runs excellently, just needs a lil love to keep things that way.

Carzy Driver

rewiring is fun, I mean it. it's not hard to do. as long as you got the connectors, wire, solder, heat shrink tubing, and some starbucks you're good to go. as for specific lenghts of wire, I don't know, depends on what you want to keep, meaning if you want to weed out the deadends

vipers

iTrader: (8)

to my knowledge, there are no available aftermarket wiring harnesses made for the fc..... and creating your own wouldnt be the best option either....... since the wiring is color coded, it makes troubleshooting much easier...... my recomendation......either purchase a new one (very expensive)...or purchase one off of ebay (or any place that sells these).... on ebay, you can get them for usually what you can at a wrecking yard. then use yours and that one, and make one good harness....

i say this from experience, i have done this myself..so i know the difficulties involved, and ive researched creating my own, and purchasing new, and this was the best way i found to revive a dead harness........... some of my wiring was all burnt and hard, and wasnt on the other harness, so i disconnected the wires one by one from their spots on the ecu plug, and thier points at the other end of the harness....and "simply" put them in place of the bad wires, keeping the same color coded wire! then electrical taped and wire loomed the whole harness and voila! a perfectly good harness!

TalkSick

i had considered the issue regarding color and had decided to do my best to match it, and very permamnently code the rest for reference. I **** you not ladies and gentlemen that unless they start testin for emissions an i cant get it passed ill drive this car for as long as it starts so im not worried about screwin the next owner with unmatching colored wires. Buy make my own i had meant that i was going to take one out of a wrecker.. match the lengths n guages with brand new wiring and reinstall franken-wires using whatever means necessary.

i would do it wire by wire but that seems rather impossible seeing as how they are bundled together throughout and a large part of the purpose behind this is to clean things up, not make a mess. Far as what i do and dont want to keep at this point, ill keep what i have and take it from there. Once ive spent a few days swearing an diggin around an learnin what's what and so on ill start worryin about other things, i have a haynes guide that will tell me all of this im sure but i am a hands on "oops i broke it" kinda learner.

banzaitoyota

Can it be done? Yes
Can it be done correctly by someone with minimal experience correctly? Not likely

Is this your only means of transportation?
What experience do you have?
What tools do you have?
How long are you planning to devote to this?
Whats your budget?
What are you hoing to accomplish?

bradenscreed

...man im backing you on this one, its not hard, and honestly i love doing wiring. just take it simple first. unwrap what you can see in the engine bay, see how many wires u have in your hand, get an idea of what youre going to be dealing with, and if it is your only means of transportation, then take digital pics, and/or have a friend with you, a second hands on opinion is always a valuble asset. get tape and label and mark EVERY wire. lots of heat shrink, electical tape, and ever kind of connection you can think of, and make sure there is a back up vehicle to drive to the store to get the parts you forgot....and most importantly, TAKE YOUR TIME, it pays to be patient!

TalkSick

yes its my only means of transport beyond bummin rides from friends.

experience wise, i have never once taken a car to a mechanic (i will spare you the list of stuff ive fixed, but at at least one point in my life ive done everything from change a tire to rebuild a couple engines), ive had some minimal schooling, i did all the physical aspects of putting the current engine in my rex and putting everything back together as i was assisting a disabled mechanic, basically just turnin wrenches where he pointed type thing :P but i am a quick learner (i didnt know at the time what the hell i was working on really an had little interest beyond gettin me paid, then i took it for a rip and managed to claim it as my own a short while later) ive installed stereos and all sorts of electrical. the task is certainly not beyond my scope.

i have all the tools i can forsee needing, as well as a garage.

i am currently on winter layoff, i have time and can live with it out of commission for a few days no prob.

budget, say a couple hundred dollars

im hoping to accomplish - the sound knowledge that if i start gettin a charge light or a short somewhere i want to know that I myself personally put the wires in and know not only that they are done correctly, but also that they are replaced by someone who gives a ****. the side effect of learnin a ton about the car as i am no mechanic really, but intend to start removing emissions control crap and unneccessary baggage as well in the near future. Making sure the wiring is in order seems a pretty good place to start seeing as how i have already had a ground short out on it, headlight switch etc etc.. i can actually see another hangin loose but havent got in to see where it belongs. wires n hoses.. first things to replace

turbo2SE

iTrader: (1)

the way i redid my harness was buy the universal ''painless'' kit i took my extra harness that was pretty much on its last leggs and used my other decent harness as a referance .took all the male/female connectors from the old harness reused them on the new harness i was going to make and traced all the connections and how long and gauge of the wire and matched it best i can.

story in a nut shell: i took non turbo harness 86 SE bought a decent 87 turbo 2 harness .and got a painless harness with SE connections . i have a copyed turbo 2 with mostly SE connections since there isnt much differance .looks clean i must say.. and works great! sorry i have no pics of my work. but you could try this .honestly i think it was worth the time and money and makes the engine bay look so much cleaner.

monty

Aaron Cake

iTrader: (1)

Not a chance. To address things in terms of money, we're talking at least $1500 to buy the harnesses from Mazda. Don't even think of rewiring them yourself unless you have a source for all the OEM connectors and several months to set up the wiring loom as the car is out of commission. So the only choice is to buy the Mazda harnesses and swap them, which can be very involved. Just swapping the emissions harness and engine harness is only a few hours, but if you want to swap the body harness you need to pull the dash. For a first-timer, we're talking about days.

What you can do in the meantime is pull each and every connector, clean with contact cleaner, pack with dielectric grease and then reconnect. Since the majority of wiring harness issues are connector issues, then this will go a long way to solving any weird electrical problems. While you're there, replace all those old sensors (engine coolant temp, O2, air temp) and service your grounds (clean, dielectric grease).

TalkSick

my concern with this route is that if i start pulling connectors im going to be at as much risk of creating shorts with these crispy old wires as i am likely to fix anything, leaving me back at at least partial rewire only now with a limping or inoperational car. im looking at a situation where i can do my best to fix it now before its a major issue, and i have lots of time. Or i can wait untill its a major issue and it will likely be while im working 11 hour shifts 6 days a week and have no time to fix anything at all and dont want to have to deal with not having a vehicle.

i appreciate the warnings as much as the "do its", $1500 for a harness seems rather pricey so i think ill be guttin a junker an usin it as a model to build a new one with and colors be damned

Aaron Cake

iTrader: (1)

The problem with building your own harness is that you need to source all the connectors. Do you know where Mazda buys all the connectors from? Neither does anyone else (well, I do ).

Don't underestimate the importance of the wire colours. Unless you follow OEM colours, then troubleshooting will become a NIGHTMARE. What if you have a problem and someone says "Well, check the lightgreen/red wire.". Now you'll have to go to the service manual, find out that wire is for a primary fuel injector, compare it to your new wiring (you DID use a different colour for each wire, right?) and go from there.

I think you will also be very surprised at the condition of your harness if you start digging ino it. Most of the "crunchy" harnesses are just bad on the outside. After you unwrap all the layers you will find perfect wires hiding inside. The issues happen near the ends of the wires because that's where the moisture gets in.