Engine Harness Modification questions...

[lonetlan]

I have built my Streetported N/A engine(S4). I re-used the harness and have been on a stock ECU since the rebuild.

When I finally upgrade to Rtek, I will make a new harness. ECU and Main harness. I would like to keep it a stock harness with integrated safety features(more than just fuses).

What can I do to the engine harness to accomplish this goal?
How should I have the PDA wired to be "apart" of the system?
What could be the best option to reduce the added resistance?

Keep these in mind:
Still have emissions
Its a S4 N/A
Cold start blocked
E=IxR
The 7 experiences all the seasons
I'm not ready for a full stand-alone ECU
75% daily driver/25% track car

I kept the topic open so we can help others with a similar dilemma.

Thank you for viewing.

[rxspeed7]

What all are you trying to gain by doing this? Just to make a new harness to cure shotty 20yr old wiring or to eliminate unnecessary wiring and fuse's?

Zack.

[Rotary Related]

I have built my Streetported N/A engine(S4). I re-used the harness and have been on a stock ECU since the rebuild.

When I finally upgrade to Rtek, I will make a new harness. ECU and Main harness. I would like to keep it a stock harness with integrated safety features(more than just fuses).

What can I do to the engine harness to accomplish this goal?
How should I have the PDA wired to be "apart" of the system?
What could be the best option to reduce the added resistance?

Keep these in mind:
Still have emissions
Its a S4 N/A
Cold start blocked
E=IxR
The 7 experiences all the seasons
I'm not ready for a full stand-alone ECU
75% daily driver/25% track car

I kept the topic open so we can help others with a similar dilemma.

Thank you for viewing.

If you're still using the emissions equipment then you can't do anything to the factory harness. Everything needs to be there. I don't know anything about the PDA's cable so I can't help you on that. Could you better describe what your trying to do. I'm sure I could answer it better then. Do you have a pin out for the PDA cable? that could be helpful if your trying to power it off the car.

[rxspeed7]

I didn't quite understand what you meant by including the pda into your harness. I know that on the rtek there is a seperate db9 cable that comes off the side of the ecu for a serial cable to a pda connects.

If your just wanting to clean up your harness i would strongly suggest just sticking with a oem mazda harness and ,maybe depinning the wires you don't need nor use, but as you said you are still running emissions. So pretty much there isn't going to be many unused wiring. As far as reducing resistance, as long as there is any ghetto hack job wiring done, you should be alright. Just be sure theres no crusty green or blue corroision on any of the wiring also.

Zack.

[lonetlan]

What all are you trying to gain by doing this? Just to make a new harness to cure shotty 20yr old wiring or to eliminate unnecessary wiring and fuse's?

Zack.
Exactly, I just want simplicity in the interior harness, and consistency in the engine bay harness.
I didn't quite understand what you meant by including the pda into your harness. I know that on the rtek there is a seperate db9 cable that comes off the side of the ecu for a serial cable to a pda connects.

If your just wanting to clean up your harness i would strongly suggest just sticking with a oem mazda harness and ,maybe depinning the wires you don't need nor use, but as you said you are still running emissions. So pretty much there isn't going to be many unused wiring. As far as reducing resistance, as long as there is any ghetto hack job wiring done, you should be alright. Just be sure theres no crusty green or blue corroision on any of the wiring also.

Zack.

Depending on which PDA I choose, I could use the 12v power wire from the cigar lighter and adapt the PDA charger into it; yes, the PDA is connected to the ECU, but the PDA will need to be charging while connected. So, it will need a power source.

I will be re-making the OEM harness(fully copying the original), but the "problem circuits" will have there(their?) own grounds instead of connecting it to a ground ring terminal. Also, I will try to incorporate a circuit breaker on the battery power wire and, 2 cut off switches. One switch to shut off power to the alternator; the other will stop power to the fuel pump.

[rxspeed7]

Gotcha, as for your interior harness, what all do you plan on keeping? Your really asking for a lot, a lot of work. It would be easier to just get a painless harness for the interior if that's the route you intend on going with.

For the engine i can understand what your trying to do and again it will be a lot of painstaking work, not to mention trying to hunt down the individual pis for each of the factory connectors. But if you decide to make it a good word of advice is that the proper crimp and contact will almost always be better than a solder joint in terms of reliability and performance.

Zack.

[lonetlan]

It reads as a lot of work, but it isn't. I'm basically copying the old one, but guaranteeing room for error. The connectors can be purchased new because Honda and some Mitsubishi vehicles use the same connectors. Better yet, the wires can be had with the exact same color identification as stock(blue/yellow and stuff) from a electronics store.

Painless harness's, to me, are for dirt track racers and dune buggies. I'd rather have an ARC 8000 harness for the interior instead; I'm still going to use the stock harness. The interior doesn't need much modification other than a relay for the power windows, which is easy. I'm relocating the idiot light board to the dash. The engine harness is going to get a lot more attention than the interior.

The way I decide on soldering vs. crimping a connection is: If its going to stay the same for a while, solder. If its going to be changed from time to time, crimp. I know what you mean though.

[lonetlan]

If I change my mind on stock connectors, I'll get these...

http://www.diyautotune.com/catalog/755-piece-weather-pack-kit-p-380.html

[Rotary Related]

Depending on how long you can wait, we will be offering replacement engine harnesses for the S4 at some point. All brand new stuff. You will be able to order it without certain connectors as well since most people do not use the emissions equipment anyways. It will be similar to the factory harness but different enough to be a bit more durable and as always use higher quality components where possible.

[Tanj!]

If I change my mind on stock connectors, I'll get these...

http://www.diyautotune.com/catalog/755-piece-weather-pack-kit-p-380.html

If you go with the Weather Packs you will need a crimp tool. The rubber plug is crimped to the wire to hold it in place. I'm about to rewire my entire SA project as most of the wiring is in poor shape (not to mention connectors crumbling when touched) after sitting in a field for some time. I'm leaning towards that same Weather Pack kit for the majority of bits and cutting factory connectors off pigtails and replacing them with weather packs for things like tail light assemblies etc. I do plan on continuing to use new OE style connectors for items that plug into the harness like the alternator however. Luckily the wiring for a SA is much simpler than a FC!

[lonetlan]

Depending on how long you can wait, we will be offering replacement engine harnesses for the S4 at some point. All brand new stuff. You will be able to order it without certain connectors as well since most people do not use the emissions equipment anyways. It will be similar to the factory harness but different enough to be a bit more durable and as always use higher quality components where possible.
That's great, I already started but, I may be interested.

If you go with the Weather Packs you will need a crimp tool. The rubber plug is crimped to the wire to hold it in place. I'm about to rewire my entire SA project as most of the wiring is in poor shape (not to mention connectors crumbling when touched) after sitting in a field for some time. I'm leaning towards that same Weather Pack kit for the majority of bits and cutting factory connectors off pigtails and replacing them with weather packs for things like tail light assemblies etc. I do plan on continuing to use new OE style connectors for items that plug into the harness like the alternator however. Luckily the wiring for a SA is much simpler than a FC!

Lucky! I'm with you on the tools, I actually made a plan for this project.

[RETed]

Weatherpack plugs are overkill for the interior.
Weatherpacks are designed for exterior use to prevent water and moisture from entering the connection.
This is the reason why they have rubber plugs in them.
Almost every connector in your engine bay is like this.
Hell, I guess it doesn't hurt to do this for the interior, but I think it's a waste of time and money.
Are you trying to build an electrical harness that'll outlast the chassis and your life? :)

Personally, I prefer Deustch stuff.
The plugs are a lot more lower profile than the Weatherpack crap.
You have the option of using machined pins (more expensive) or stamped and rolled pins (on a budget).
Only caveat is that the crimper can be big bucks for the machined pins.

There is nothing wrong with a crimped connection.
A crimped connection can be just as good, and sometimes better, than a soldered connection.
Soldered connections have a disadvantage in the automotive environment as they can fail due to vibration and moisture - this is where a properly crimped connection is superior.


-Ted

[Rotary Related]

Are you trying to build an electrical harness that'll outlast the chassis and your life? :)

-Ted

That sounds like the products I make. Most of them will outlast the vehicle they came from.

I agree the weatherpack is a bit much for an interior. That's kinda a waste of money. For cheapness sake you could just use 093 molex connectors from radio shack to do the same thing for 1/3 the price. And they are a lot more compact. Widely available as well.

[NoDOHC]

Ted is right about the crimps vs. Solder. The Solder makes a good connection - electrically, but the wires get bent a lot more on the edges of the solder and it is much more likely to fail - mechanically. The OEMs all run a single wire from point A to point B. Where I have seen a splice in an OEM harness, it has been crimped and sealed. There is a reason that they do it this way and it isn't cost. Sealing is critical to avoid corrosion on crimp connectors.