Wiring help in Houston?

[blk96gt]

I don't either, but the Australians are saying these carb things are the Next Big Thing. Don't you want to be on the bleeding edge of technology?

[marshall_mosty]

Just think of the HP gain you will have when you can get a smaller alternator and have less engine loss when the field energizes... Oh wait, it's CMC and you have to run OEM replacement stuff... Nevermind.

[AI#97]

If you were to run a carb and mechanical fuel pump, there would be little need for an alternator stock or aftermarket.

[marshall_mosty]

Just wire in a magneto.

[blk96gt]

So I've been doing some more research and reading on this wiring crap. It appears the chassis harness is basically the same as the sn95 5.0 harness with PATS and a couple other things added in, and the sn95 isn't much different than the fox. I think I have a pretty good idea on how to go about this now, but was hoping to talk to someone that had some experience wiring up a fox or sn95 before I went any further. Not planning on making any huge changes.

If anyone's had success doing some custom chassis wiring on a 5.0 drop me a PM. This is only the chassis harness, and nothing on the engine/PCM harness will be touched.

[Tilton]

After gutting the interior of my car and tracking it a few times, I knew if a connector was unplugged (from the dash back) it could be cut and wires traced back and unpinned. This was speaker wires , inertia switch, reverse parking lights, key-less entry (woohoo '95), ABS sensors, console lighting, electric seat...basically a lot of wire. Behind the dash you need to be a bit more careful. The A/C, radio, and airbag stuff was all taken out and unpinned as well ,but by this point I was getting greedy with unplugged connectors and removed my service port to the computer. Since it is OBD1 it isn't such a big deal to me. Under the hood, I cut out all light and cruise control connections and unpinned them from the fuse block. In the end my biggest mistake was removing a wire that sent a 12v signal to the starter relay. I was lucky Wade was in town that day and helped me trace that issue.

I don't know the exact weight taken out of the car but the simplicity of it all now is awesome. Just take your time.

[AI#97]

I "de-wired" my car a LONG time ago basically the same way you and Tilton did. Stop there, it's good enough. If you go custom, you will have to document EVERYTHING you do. Right now, you have a factory harness that is well documented on the web and can be more easily diagnosed even in its gutted state. Keep it simple. find something else that is going to net gains on track. Research roll centers and test spring rate changes due to the new tire. Start looking at shocks and re-valving them...BIG time to be found there compared to what most of CMC is running. Focusing on 4 to 6 more pounds of wire is pointless if what is there is working and is reliable. If you think it's ugly, hide it with tape or under the dash.


It takes a few years to consider all this stuff but my foray into shocks has netted a TON of time on the mustang and probably 3 full seconds on Misty's Camaro. Anyway, good luck.

[blk96gt]

Yeah I basically did the same as Tilton did. Currently I've removed all the wiring for the radio, cruise control, headlights, fogs, ac/heater, radio, doors, windows, defroster, parking brake lights, cig lighter, keyless entry/anti theft (excepting PATS), stock fan wiring (have mine on it's own switch), main headlight switch, abs, and a couple other things I'm forgetting.

The main thing I would like to do is rewire the ignition switch. The way the aftermarket switch is wired up now is just stupid. The wires from the aftermarket switch are spliced into the ones from the stock switch. It's a problem waiting to happen, and I'd just assume get ride of the stock ignition switch at this point. Problem is I have no clue how to properly wire up the switch to get power to everything.

The two other things I thought about doing were relocating the CCRM and engine compartment fuse box. The power wires coming out of the fuse box now either go inside the car or to the ccrm. If the ccrm is inside the car, I don't see any need to have that box in the engine compartment.

[blk96gt]

I guess the short of my post above is that if someone has some time one evening or on a weekend, I'd like to be shown the proper way to wire up the ignition switch. I'm not against removing the aftermarket switch and push button start, but since it's already on the car I figure I may as well use it. I also have some questions on the proper way to wire up the master switch, as I think my current method is incorrect.

[blk96gt]

I'll also add what I've discovered about PATS, since there's not much online about it except a bunch of posts saying to tune it out. I'll start by saying again that the 4.6 harness is not much different that a 5.0 as far as the chassis harness goes.

The PATS consists of 3 pieces, and as long as you don't remove any piece of the system it will keep functioning.
1. The key, which has a chip in it.
2. The transceiver module, located under the steering column
3. The PATS control module, located by the I/P fuse panel.

When the car gets power when the ignition is switched to run/start, the transceiver module checks to make sure the key matches what the PCM has programmed in, and the car will start. If the key doesn't match, the car will turn over and all the accessories will work, but it won't ever start (can't remember if this is due to the PCM not sending power to the injectors or coil packs). There are another group of wires that run to where the key goes, but those have to do with the keyless entry/anti-theft, and can be removed. The keyless entry is tied into the PATS system, but if the keyless entry/anti-theft module is removed, then the one wire that runs to PATS can be removed as well. If I remember right, that wire is pin #5 on the connector for the transceiver module, and it's the ignition interrupt wire.

What all that means is that you don't have to have the stock ignition switch installed, despite what I've read elsewhere. This also means all that PATS needs to enable the car to start is to have the key somewhere in the vicinity of the transceiver module. My plan is to tape the key to the module, bundle all the PATS crap together, and tuck it somewhere out of the way.

The easy way to test to make sure PATS is still working, other than starting the car, is to put the ignition switch into the run position and watch the light. If the Theft light comes on for 2 seconds and shuts off, PATS is still happy. If it does anything other than that, then PATS is not working properly. If the car still starts if the Theft light is anything other than off, then PATS has been tuned out.

Anyways, maybe this will help someone out in the future if they want to know about de-wiring a 4.6. Despite what everybody likes to say, the chassis wiring is no more complicated than the newer Foxes and sn95 5.0's. From what I can tell, the chassis wiring is exactly the same from 94-98, except for PATS. Despite the chassis harness being a mess, Ford actually did the engine harness well. There's really not much to gain from de-wiring the engine harness unless you want to get rid of the emissions crap.