88_N/A_GXL

iTrader: (3)

Okay guys, so I'm tired of fighting 26 year old wiring in my '88. I've decided I'm going to go through and rip out every single wire, nose to tail, and removing every universal/deleted/unnecessary wire. Basically leaving the MS3 wiring, lights, security, wipers, and doors. I know I'll be removing the autotragic wiring, been told it's on 5-speeds as well, and I'll be removing all the wiring for the rat's nest solenoids, AC, PS, and anything else I'm forgetting. Also, I will be relaying my doors and sunroof while I'm in there.

Has anybody done such a complete/monumental rewire on their 7? If so, any tips/tricks? Also, where can I find any/all connectors for the stock lights, wipers, doors, etc? I plan on using weatherpak connectors on all the MS stuff and I already have loads of newish injector connectors laying around but want to start fresh on connectors for everything else. Basically a brand new custom complete harness.

Hopefully I can remember to take pictures for everything and maybe have a "build" thread about it.

clokker

iTrader: (2)

I've totally rewired a FD, partially redone my FC and am now completely rewiring a Z, so I have a bit of experience.

Since you're willing to undertake the project, I'll assume you understand the schematics/circuits and are comfortable modifying them.
My advice then is to decentralize the system.

When you pull the stock harnesses (itself a big job...), lay them out and compare to the schematics.
You'll find that much of the complexity/clutter is due to the centralized design of the harness..everything homeruns back to the giant fusebox/connector junction in the footwell.

I start by laying a power grid into the chassis, a main power feed from the battery (wherever you've located it) to the nose of the car, to the rear and to the cabin.

You then site the appropriate relays/fuses as close to the end components as possible.
For instance, in the Z the rear electrical center (located in the passenger bin) has the relays/fuses for the rear running lights, brake lights, fuel pump and rear window defroster.
The front (at the radiator bulkhead) has relays/fuses for headlights, driving lights, efan and horn.

The harnesses from these "centers" back to the cabin and controls are very small and really only carry the coil trigger current (mostly).
You've isolated the high power circuits from the control circuits and probably eliminated 50% of the wire length necessary.

Your biggest problem/headache will be integrating the FC controls/switches into the system...they are incredibly proprietary and difficult to substitute (I've tried...) and unless you're deleting the stock dash, you're basically stuck with them.

Good luck.

88_N/A_GXL

iTrader: (3)

Wiring is a joy to me, so it's no issue modifying circuits and reading schematics.

I don't know if I'd go as far as decentralizing the whole system, it's a great idea though, but besides my 0awg wire running to my stereo in the back I'd rather not have any more large current carrying wires in the cabin than needed. I know fuses are a safety feature but it's still a thing I don't like. That and the way I imagine it it would be a bunch of different fuse panels at each end of the car.

I've been doing more research and I think I'm going to pull the underhood and interior fuse panels from some vehicle at my local u-pull-it. Everything is going to be relayed that can be, windows, headlights, tail lights, sunroof, pretty much anything with a significant draw that I haven't already relayed. I've already relayed my pump and efan. And thanks for reminding me that I can mount a few relays up front under my rad panel, completely spaced that for a second.

I also think that a lot of the clutter under the dash is for the HVAC, which I plan on completely removing, though I may setup some kind of vent for the windshield. I also plan on moving my MS3 from the stock ecu location up to the firewall.

My understanding of electrical systems says relays and fuses should be as close to the battery/junction point as possible.

As much as possible, I plan on changing any connector I can to "dime a dozen" types that can be had almost anywhere if necessary.

I think I've hit almost every great point you've brought up. Always love to read your input on any discussion clokker. Thank you.

Innovation

iTrader: (1)

Please post your progress with some pics. I'm very much interested in this topic.

toplessFC3Sman

iTrader: (1)

As a counterpoint to Clokker, I'd recommend keeping the fuses as close to the battery in a central location as possible. It does increase the "bundle of wires" running around the car, but I'd prefer to keep as little un-fused wire in the car as possible, so that you can't rub through or accidentally crimp (or have the potential for that to happen in an accident, for instance) one of the un-fused 12V wires & blow your battery up/melt stuff/burn the car down.

At the very least, I'd put a giant 150 - 200 amp breaker as close to the battery as possible, and at least some fuses to break the 12V power down to the general sub-system level. You'll need that high of a rating to handle the instantaneous starter current without tripping. From that point, as long as there are no un-fused wires running throughout the car, if you wanted to have front & rear local distribution blocks or similar, go for it.

EDIT: DIYAutoTune has a kit with a whole bunch of weatherpack connectors of different sizes, with the pins, o-rings etc to keep everything sealed up, for a pretty good price. I bought it a few years back, and it's been very helpful for wiring on the 7, a motorcycle I've re-wired & am fuel injecting, and a few other projects. I haven't bought the crimper, instead crimping with pliers, then soldering, but this is personal preference. I'd definitely recommend one of the kits though!

88_N/A_GXL

iTrader: (3)

Yea, those were the weatherpack kits I was looking at as well. I don't mind a bundle of wires running through the car for things that are actually being used, I just don't like when there's all the extra that isn't being used like the AAS, A/C, automatic trans, etc. That and no wire, besides my audio wires and windows/sunroof, should be larger than probably 12-14awg when I'm done. If I switch to LEDs all around the car, which I do plan on doing, I could probably even go smaller on wire.

It seams as though a 96-99 Taurus underhood and interior fuse panels will work great, 175A mega fuse which I will be running to my 3G alternator and then one or two of the Maxi-fuse spots to run power into the interior panel when I rewire/repin both.

I would never run an un-fused wire through the car and I'd be hesitant to run any under the hood as well but, I think stock the starter cable is and I'm running my ~6" alternator cable unfused, running a side mount, but those are both pretty secure right now and have no place to rub against and wear.

unek87

Looking forward to the finish project ahead . I've been down this route in my own fc . Got tired of all the wiring mess which most if not all in certain places wasn't even needed or needed to be relocated . Front Chassis harness has been removed , stripped of all unused **** , extended and tucked inside the front clip on both sides . Battery and main fuse block relocated to bin behind seats . Charging system completely rewired . Haltech engine and coil harness's tucked .. It's taken a lot of work but in the end when your trying to pin point a possible wiring issue in the future is SO much easier . Good luck brotha

digitalsolo

iTrader: (2)

I've rewired the entire 2/3rds of my FC (still need to clean up the tail light area). I moved all of the wiring out of the bay, hid the leads for the lgihts in the fender and put the fuseboxes into the rear driver side bin (battery is in passenger bin). Pulled the dash harness out of the dash and integrated it into the firewall harness so that I can pull the dash with no wiring removal.

Custom gauges, scratch built engine harness, stand alone engine management, etc. It's very tedious but doable.

Some tips/tricks:

Use glue shrink
Buy proper automotive grade TXL/GXL wire, lots of sources for it.
Depin the Mazda connectors and repin/reuse them for all the Mazda specific stuff (like HVAC, etc.)
Take lots of pictures/notes, the first time you do it it's easy to get lost.
You can get rid of your main relay if you feed an ign accessory (not on during crank) +12 to the green/black wire at the HVAC box. I don't know if the main relay does anything useful for the rotary, I don't have one.

88_N/A_GXL

iTrader: (3)

Thanks guys. DS, I was planning on some TXL wire for everything in the car and GXL for everything under the hood.

I'm still in the process of writing down and eventually drawing up my own diagram of what I'm going to need. The hard part is remembering everything I need, almost forgot my washer pump yesterday lol.

Can you explain why a 12v would need to go to the HVAC box? I plan on removing everything HVAC related so I'm confused.

I also plan on putting something on different key positions, mainly windows and sunroof on ACC, that way whenever I'm just sitting I don't have to prime my fuel pump just to roll down a window. Would there be any issues with that?

Aaron Cake

iTrader: (1)

That basically defeats the purpose of the fuse.

The fuse is not to protect the device, but to protect the wiring to the device. If that wire shorts to chassis along its length and the fuse is at the device, the fuse does nothing and the wire becomes an instant fire.

88_N/A_GXL

iTrader: (3)

That's what I thought Aaron.

unek87

Pencil, note pad and colored pencils are your best friend through something like this . I have a notebook with chassis and engine harness lay out that I keep in the car

88_N/A_GXL

iTrader: (3)

Colored pencils are a great idea.

boricuarx7

Sorry to not be able to add insight to this tread (its way over me..) but I am looking for electrical harness for my NA '86... has streetport done and converted to Holley 4 barrel carb.. I have electrical issues now... thanks for any guidance..

clokker

iTrader: (2)

You are right and I am wrong.
Mostly.

Turns out, VW/Audi do just about what I want and have the part to fix my omission.
If I can adapt it to work, that will be great, if not, the concept is adaptable to the setup I already have.
Basically, they have a power distribution block with fairly large fusible links and these cables then travel to smaller sub boxes where each circuit gets individually fused.

88_N/A_GXL

iTrader: (3)

So basically a big fuse box to feed all the little fuse boxes at the components?

clokker

iTrader: (2)

Yup.

88_N/A_GXL

iTrader: (3)

That'd be nice. Big one for under hood and feeding one under the dash for everything there and one somewhere in the back for lights and fuel pump and stuff. Have to find a suitable place in the very back to mount the rear box.

j9fd3s

iTrader: (3)

this is how Mazda does it. in concept the FC works like this.

power goes through the main fuse, to the main relay, where it branches into the other power wires in the underhood fuse box, which then either do what they do, or go to the fuse box under the dash, and then go do what they do.

we can argue about Mazda's execution, but in concept its already there

clokker

iTrader: (2)

Yes, indeed.

The only difference is that I won't have one big centralized fuse/connector box, the substations will be spread around more.

88_N/A_GXL

iTrader: (3)

Clokker was taking it a step further, putting a fuse panel in the back for things back there. Mazda has just one interior fuse panel up front for everything inside the car.

I will probably be running only 2 panels myself as I really don't see a need for something in the back for 2 systems, fuel pump circuit and rear lights, I don't think there's really anything else back there.

clokker

iTrader: (2)

I'll have relays/fuses for fuel pump, brake lights, running lights and rear defrost back there.

dguy

iTrader: (8)

Do yourself a favor and just set aside a budget for a PDM. I've been using MoTeC PDMs for a couple years and they're great. Saves me money by saving my time in the long run. Racepak also puts out a product thats similar but more economical. I'm not a fan of the ISIS gear.

-David Guy
MEP

88_N/A_GXL

iTrader: (3)

Yea, forgot about the rear defrost Clokker.

Dguy, I've been looking into the Racepak Smartwire but that's a little out of the budget right now. I'd love to have that and an IQ3 some day.

88_N/A_GXL

iTrader: (3)

Well, got the Taurus under hood fuse box and unpinned it. Come to find out, it's almost impossible to find female terminals for the MAXI fuses... guess I may go looking for something else. Unless someone here knows where I can snag some?