Engine Wiring 101

[Fendamonky]

Hey guys,

I'm making this thread in hopes of having a place where the experienced members on the forum can compile a good amount of information, links, and discussion regarding one of the most critical (but least understood) components in any modified car: The Wiring Harness.

I figure the task of wiring can be broken down into a couple different subjects: Theory and Principles, Consumable Equipment (sensors, wires, connectors, external protection, etc.), Tools Required (crimps/solder, cutters, strippers, etc.), Best Physical Practice (the HOW of making the harness).

Basic Principles - Wiring and electronics are PFM to me. What are some of the basic principles people should understand before jumping into a wiring job? (Any links to good educational/resource sites and pages)

Necessary equipment -

Wiring/sheathing: What kind of wire is the best for engine work vice interior (and why?). Heat Shrink vs electrical tape, environmental and/or heat protections, etc., etc.,

Connectors: Which brands are quality and which ones should be avoided? Which kinds are we likely to see most commonly? External power or self-powered?

Tools Required- We're only as good as the tools we use, right? Lets discuss the range of options (from the $15 Advanced Auto/Harbor Freight special, to the paycheck depleting "MilSpec" jobbies)


Best Practice - Doing it right takes time, doing it multiple times is a waste of time.. How do we do it right the first time??

Stolen from rbracing-rsr.com:

Originally Posted by ECU Wiring Harness Construction

Concentric Twist Layers

The stiffness of the harness will depend largely on how the underlying wires are arranged. The correct method is concentric twisting where successive layers are twisted in opposite directions...One wire surrounded by six wires, with each successive layer adding six additional wires i.e. 1-6-12-18. The twisting of the wires gives the harness additional flexibility and reduces strain on the wires. The above table provides some insight into the methodology.

Crimping vs Soldering -I know there are two different "camps" when it comes to wiring; Crimpers and Solderers, what are the pro's and con's of each and the differing justifications?


General Online Resources:
Links- http://www.rbracing-rsr.com/wiring_ecu.html // http://www.rbracing-rsr.com/sq6wiringloom.html
Theory -
Supplies - http://www.prowireusa.com/
Decent "How To's" -
Misc -

[Rotary Evolution]

i always prefer a new harness over an old one but the following are steps i use to buy more life from marginal, old, original wiring:

convoluted tubing over areas that contact metal where it can rub through the harness or are draped over high heat areas.

most electrical tape you find just about anywhere is garbage. heat, fuel and oil unravel it as the adhesive melts or is compromised by fluids. don't even bother with vinyl electrical tape unless you know it can handle the job, such as an industrial grade wrap. self bonding silicone tape is better for a base insulator under convolute tubing or the actual friction covering.

for actually wrapping the outside of the harness i personally prefer either 3M friction tape or another brand of friction tape which contains more tar. it is self sealing, weather resistant, won't unravel, heat resistant and protects the harness quite well. if it comes in contact with oil or fuel it will get sticky but it won't be compromised.

if you're going to crimp versus solder, find the self sealing shrink tubes that will reinforce and seal the butt joint.

the biggest thing about wiring isn't so much the wire but the wire insulation. after years sitting in a 200F engine bay the insulation gets brittle and cracks, exposing the wires where they will begin to fray and oxidize. new wire is always preferred so that you can buy many more years before it begins to do the same. if an insulator is cracked and wires exposed but not compromised you can seal it up with liquid tape to buy a few more years without digging deeper into the harness and repairing it.

if you're stripping wiring from an old harness to repair it, hold a lighter under the insulation you're stripping for a few seconds to warm it up and then strip the wire. this helps you strip just the insulator without inadvertently taking half the core wires with it.

always double check to make sure your wiring isn't getting pinched under a bracket, resting on a sharp piece of metal or sitting exposed in an area with moving parts such as next to the throttle linkage.

[Kontakt]

Here is the crimper that I picked up recently and have so far been rather pleased with. I got it to put together all of my Anderson Power Poles for HAM and R/C hobbies, but I got the full set of jaws for other purposes as well. You can adjust the release point for the ratchet to adjust the force with which they close and how far they close to some extent.

If anyone else has any longer term experience with these, feel free to chime in, but so far they have been a great reasonably priced crimp tool for my needs.

http://www.powerwerx.com/crimping-to...foam-case.html

[Prodigy]

Sub'd

I've only gone so far as to thin out and re-fresh a harness without building from new... This will be a great thread, just need to point Peter & Brian in its general direction... :P


J.

[Kontakt]

I told Brian he should photoblog the evil Jeep wiring problem hunt he's taking on in the next few days. I'm pretty sure it'd have more entertainment than education though.

[TitaniumTT]

Originally Posted by Kontakt

I told Brian he should photoblog the evil Jeep wiring problem hunt he's taking on in the next few days. I'm pretty sure it'd have more entertainment than education though.

It would be pictures of an engine harness, chassis harness, and trans harness laid out on massive workbench with Starbcks Energy drinks and empty packs of cigarettes laying around and if you look closely in the refection of the SS workbench you may catch a glimpse of a nekkid blondehaired ape looking figure scratching his head and spitting on the floor while throwing feces at a particular Grand Cherokee....

I may take your advice on the harness for the 'vert.... although I think karak won't approve as it is the complete opposite of everything that he just posted.... which I will address after I crack open another starbucks and find a pack of smokes....

[TitaniumTT]

Originally Posted by Rotary Evolution

i always prefer a new harness over an old one but the following are steps i use to buy more life from marginal, old, original wiring:

Marginal wiring is a popped engine waiting to happen... would you put marginal gas in your rotary? Why is marginal wiring acceptable?

Originally Posted by Rotary Evolution

convoluted tubing over areas that contact metal where it can rub through the harness or are draped over high heat areas.

I hate convoluted tubing... fucking disgusting shit. First of all, if it's rubbing, secure it. Second, that tubing likes to melt. It doesn't belong in an engine bay.

Originally Posted by Rotary Evolution

most electrical tape you find just about anywhere is garbage. heat, fuel and oil unravel it as the adhesive melts or is compromised by fluids. don't even bother with vinyl electrical tape unless you know it can handle the job, such as an industrial grade wrap. self bonding silicone tape is better for a base insulator under convolute tubing or the actual friction covering.

ALL electrical tape is unsuited for an engine harness.... that is all. PERIOD! If you have a wire that's been compromised, cut it, cut it back, strip it, apply some adhesive lined heat shrink, crimp it, and heat it.

[QUOTE=Rotary Evolution;260337]for actually wrapping the outside of the harness i personally prefer either 3M friction tape or another brand of friction tape which contains more tar. it is self sealing, weather resistant, won't unravel, heat resistant and protects the harness quite well. if it comes in contact with oil or fuel it will get sticky but it won't be compromised.

ALL electrical tape is unsuited for an engine harness.... that is all. PERIOD!
I cannot stand when someone says, hey Bri, what do you think of my wiri..... and I get all pissed off because I see it wrapped with about a 1/2mile of fucking tape... get some damn Raychem or something equivalent... damn...

Originally Posted by Rotary Evolution

if you're going to crimp versus solder, find the self sealing shrink tubes that will reinforce and seal the butt joint.

Good luck bundeling those massive things. Don't forget either, if you use the wrong crimpers you'll slice the massively ginourmous heatshrink and it will just peel back exposing the crimp. I use those in one place and one place only, maring wiring because they are required by the CG, other than that, they are fucking trash... expensive trash to boot.

Originally Posted by Rotary Evolution

the biggest thing about wiring isn't so much the wire but the wire insulation. after years sitting in a 200F engine bay the insulation gets brittle and cracks, exposing the wires where they will begin to fray and oxidize. new wire is always preferred so that you can buy many more years before it begins to do the same. if an insulator is cracked and wires exposed but not compromised you can seal it up with liquid tape to buy a few more years without digging deeper into the harness and repairing it.

Did you really just say seal it with liquid electrical tape? Wow.... don't even know how to respond with that one expect... it's wrong? See above with the cut strip crimp heatshrink.... why Band-Aid something that can actually be repaired properly?

Originally Posted by Rotary Evolution

if you're stripping wiring from an old harness to repair it, hold a lighter under the insulation you're stripping for a few seconds to warm it up and then strip the wire. this helps you strip just the insulator without inadvertently taking half the core wires with it.

Or... OR.... buy the proper stripper? I've never, even with old nasty stock wiring like repining a fucking TPS on the 3rd gen crispy bakes oven engine harness have I broken half the core wires....

Buy the right tools, buy the right crimpers, plan it out, do it once, don't repair shit, there should be zero butt connectors in an engine harness, take all your electrical tape and throw it away when you're building a harness unless you're using it to temporarily bundle wires, Raychem is your friend, spend the money, like levi said though, unless you're planning on doing a few of these, have some different requirements, or just want to take pride in your work, there are better alternatives. I've seen rywires and while they aren't the greatest of fitting harnesses, they use tefzel, they use Raychem, they use adhesive lined heat shrink... I have no idea how they build them as cheap as they do.... for me to do a fully custom engine harness with the bulkhead connector and wire in an ecu and get the car started, you're looking at ~$2k.... but..... at the end of the day, it will last longer than your car and you'll never have to worry about it.

Now.... I'm going to throw feces at a certain green jeep......

[RETed]

Originally Posted by TitaniumTT

although I think karak won't approve as it is the complete opposite of everything that he just posted.... which I will address after I crack open another starbucks and find a pack of smokes....

+1

I do use 3M Super 33+ when it's a last resort.
It's usually because I can't get a crimp tool due to restricted location and / or I'm too lazy or ran out of time to redo the whole thing properly...


-Ted

[RICE RACING]

Two words:

SCOTCH LOCKS!





Quality ECU instal harness NOTE: wiring conduit = professional = Australia #1 ECU for rotaries = WINNING!

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[Fendamonky]

Originally Posted by Rotary Evolution

i always prefer a new harness over an old one but the following are steps i use to buy more life from marginal, old, original wiring:

For the purpose of this thread lets assume that all wiring is new, there are no reused connectors, and we're not splicing into a pre-existing wiring harness.

Assuming we're working with the initial items of several different spools of wire brand new connectors, and brand new ECU outs with short (if any) leads.

Originally Posted by Rotary Evolution

the biggest thing about wiring isn't so much the wire but the wire insulation. after years sitting in a 200F engine bay the insulation gets brittle and cracks, exposing the wires where they will begin to fray and oxidize. new wire is always preferred so that you can buy many more years before it begins to do the same.

What, specific, insulation are we looking for in the wiring? What are the good options, the bad options, and the "wtf is this doing in a VEHICLE??" options?

Originally Posted by TitaniumTT

Marginal wiring is a popped engine waiting to happen...

With this in mind Brian, what would you suggest as the shopping list prior to attacking the chore of building a harness from scratch?
Obviously you're going to need wiring (suggestions on a specific brand or style to look for?), Connectors (as applicable to your individual setup), Environmental Protection (Raychem and heat shrink, to keep the wiring protected and organized: Any suggestions on specific types and specifics?), and a way to attach the wires to the connectors (suggestion on specific crimps that are worth getting, or confirmation on the one Whoop suggested, types to look for and/or avoid, etc., etc.)

Originally Posted by Not-so Angry Brian

ALL electrical tape is unsuited for an engine harness.... that is all. PERIOD! If you have a wire that's been compromised, cut it, cut it back, strip it, apply some adhesive lined heat shrink, crimp it, and heat it.

I would assume the electrical tapes primary use would be for bundling wires while sliding the main sheath of raychem over the whole harness

Originally Posted by Brian

Good luck bundeling those massive things. Don't forget either, if you use the wrong crimpers you'll slice the massively ginourmous heatshrink and it will just peel back exposing the crimp. I use those in one place and one place only, maring wiring because they are required by the CG, other than that, they are fucking trash... expensive trash to boot.

What would be the correct crimpers to use in an instance like this?

Originally Posted by Brian

Buy the right tools, buy the right crimpers, plan it out, do it once, don't repair shit, there should be zero butt connectors in an engine harness, take all your electrical tape and throw it away when you're building a harness unless you're using it to temporarily bundle wires, Raychem is your friend, spend the money, like levi said though, unless you're planning on doing a few of these, have some different requirements, or just want to take pride in your work, there are better alternatives.

I know this is just a repeat of my previous replies, but would you go into more detail regarding what ARE the correct tools and supplies to use? (I know you've got plenty of stuff going on that takes priority, but if you could expound on the right stuff verses the wrong stuff that would be fucking awesome!!)

Originally Posted by Brian

I've seen rywires and while they aren't the greatest of fitting harnesses, they use tefzel, they use Raychem, they use adhesive lined heat shrink... I have no idea how they build them as cheap as they do.... for me to do a fully custom engine harness with the bulkhead connector and wire in an ecu and get the car started, you're looking at ~$2k.... but..... at the end of the day, it will last longer than your car and you'll never have to worry about it.

My guess is that they buy their supplies in bulk, and they just have jigs made up so it's stupid easy for them to kick out looms after the first one is made..

Originally Posted by Bri-face

Now.... I'm going to throw feces at a certain green jeep......

This wouldn't happen to be that one I found... would it??

Originally Posted by RICE RACING

Two words:

SCOTCH LOCKS!

Quality ECU instal harness NOTE: wiring conduit = professional = Australia #1 ECU for rotaries = WINNING!

Not sure if you're having a laugh here . Because, well... I don't know much (read: anything) about wiring, but that seems a bit off to me... lol

[Kontakt]

^ Nope. Scotch locks are where it's at.

One adjustment though. Don't crush them with pliers. Just sorta flap the lid/latch over, and push it down with your thumb some. If you use pliers, you might damage the wires.

[Kontakt]

Originally Posted by Fendamonky

With this in mind Brian, what would you suggest as the shopping list prior to attacking the chore of building a harness from scratch?
Obviously you're going to need wiring (suggestions on a specific brand or style to look for?), Connectors (as applicable to your individual setup), Environmental Protection (Raychem and heat shrink, to keep the wiring protected and organized: Any suggestions on specific types and specifics?), and a way to attach the wires to the connectors (suggestion on specific crimps that are worth getting, or confirmation on the one Whoop suggested, types to look for and/or avoid, etc., etc.)

Next time I see him, I'll try to remember to bring my Tri-Crimp, and see about getting an opinion on it. I have no idea how common they are outside of the radio nerd crowd.

[Kontakt]

For variety, here is another that I considered while shopping. I probably would have given this one a shot if they had the APP jaws that I wanted, but they don't. This may be a good option for people who have no need to crimp Anderson Power Poles. These I have no experience at all with, but have read fairly positive things online about.

Use the Amazon link to shop for Astro Pneumatic 9477 Interchangeable Tool.

Edit: I'm fairly sure this is a Sealey AK3857, and also the Ideal Crimpmaster. They appear to all be the same.

[88turboii]

here are the connectors for the FD and S5 FC if you are inclined to rebuild your factory harness or make a new harness for powerfc

http://www.te.com/catalog/pn/en/917981-2?RQPN=917981-6
http://www.te.com/catalog/pn/en/917989-2?RQPN=917989-6
http://www.te.com/catalog/pn/en/917992-2?RQPN=917992-6

[Fendamonky]

Originally Posted by Kontakt

^ Nope. Scotch locks are where it's at.

One adjustment though. Don't crush them with pliers. Just sorta flap the lid/latch over, and push it down with your thumb some. If you use pliers, you might damage the wires.

When/why would you use them and in what capacity?

Just looking at them I, as a layman, would see them as a bulky alternative to crimping wires together. Obviously that isn't the reality of their usefulness though, else they wouldn't be suggested.

(No offense in questioning you Peter, I was honestly unsure if that was a dig against malpractice, lol)

***I'm not coming into this thread with any preconceived notions or ego, so any time where I question what somebody states please read it as genuine curiosity and a thirst for more in depth knowledge, NOT as a challenge to what is being said***

That being said, I *do* think that (civil) discussion and/or debate over what is the "best practice" would be awesome!!! As this would offer obviously differing view points on the subject, and their merits.