Engine Wiring 101
 

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:
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 -

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.

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

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.

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....

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

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.

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...

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.

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? :dunno: See above with the cut strip crimp heatshrink.... why Band-Aid something that can actually be repaired properly?

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......

+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

Two words:

SCOTCH LOCKS!

http://0.tqn.com/d/autorepair/1/0/h/...h-clamping.jpg

http://67-72chevytrucks.com/vboard/a...2&d=1228540861

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

[img]http://imageshack.us/a/img13/7480/i9eq.jpg
[/img]

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.

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?


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.)



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

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


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!!)

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..

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

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

^ 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.

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.

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.

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

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.

they're fucking with you, even the cheapest builds i have to dick around with i would rather stab myself with a spoon than put a scotch lock on a car...

of course now they're going to argue that scotch locks do have a place just to prove me wrong. :)

Super 33+ is the only one I will use, and as stated earlier, it's primarily for bundeling.... I don't use it for insulation purposes.

:smilielol5:

Generally a new ECU will come with a "harness." Some are better than others... I very much dislike the helltech harnesses & wires... I feel that the insulation is very thick which just increases the size of the bundle and makes the whole thing a bit more daunting.... Tefzel is where it's at...



See above... anything bought at autosuck or any of the equivalents is pure garbage. For non engine harness wires I get the TXL from a variety of different sources.... anything engine related is Tefzel, there is a Mil-Spec number that I cannot remember but it can be purchased through Pro-Wire USA is the cheapest I've found, for the Raychem stuff as well....

I'll take a picture in the next few days....

See above as to what the ECU comes with

Deutsch DTM, DT, or DTP depending on current load, the reality of it though is that you don't need very many of these... fuck... I wish TeakFC3S was still up.... fucking queen asshat did a helltech install tips thread... I puked laughter all over the place... fucking retard put in a weatherpack 6-pin connector to build a subharness for his fuel injectors... sooooo many things wrong with that... weather packs being rated for like 30A, splicing wires in a harness, soldering on little pieces of tin, breaks in the wires, zomg,.. what a loser....

Raychem DR-25 is the norm. Doublelined polytolephin adhesive lined heatshrink, either a 2:1 shrink or a 4:1 shrink depending on what is being shrunk....

To many variables, you'll be buying a few different crimpers depending on the connector....

Yes

Look at places like waytek and terminal supply co, they have a list of the crimps and the correct crimpers.


I will take a picture, you will ship me your car ;)

More than likely... they are nice for the money, but there is still ALOT to do even after you get their harness....

Yes.... it's going on CL for $2750 after I figure out what the fuck is up with it... already bought Maggie a new Jeep, mechanics special with a totally unmolested wiring harness.... only needed a rebuilt head... fucking thing is MINT

Big Laugh

:smilielol5:

I wanna see!!!!

they are totally useless

They have two places.... either in the trash or falling out of harness into the mouth of the person using them choking them to death.... or Peter cramming them down BDC's throat.

Lets put it this way.... when we redid the shitty stock harness in the Landi, $1400 ... One Thousand four hundred dollars was spent.... and not one wire was bought... I already had like 20 spools.... and all the tooling.... the DMC crimpers I have were $317 and the battery cable crimps ... and most of the others range from $80-100 each.... I have like 7 pairs of crimpers...

I keep rolls of 33+ and 88 around for different purposes. They're rarely used on wire though. :lol: 88 (heavy duty 8.5 mil) and 22 (extra heavy duty 10 mil) work a bit better for a lot of the things I actually use electrical tape for than 33+. It gets used like stretchy duct tape for things like keeping window a/c units from rattling so much. I can't say that I've ever wrapped a harness with them, though.

I really think you'll be fairly well impressed at the price point. The crimpers by themselves with just the PP jaws and no case are only $40, but they're no lightweights.

We'll have to do some side-by-side testing vs the "official" tools.

Link to Bosch Fuel Injector connectors male and female.

Even some other Mazda connectors.


http://www.fiveomotorsport.com/electrical-connectors/

Thanks for saving me the time. :lol:

For wire, I use mil-spec M22759/16 for just about everything that's being made from scratch and not using a manufacturer's flying lead. It's commonly referred to as Tefzel. Raychem Spec 44 and Spec 55 would be the next step up. There are shielded and twisted pairs of all three available. Just depends on how anal you want to get with everything. Like everything, there is hobby level that performs well and won't require a 2nd mortgage and then there is LMP spec that is complete overkill for most anything this side of La Sarthe.

www.prowireusa.com has a great selection of Tefzel, Deutsch DT* connectors, mil-spec and Deutsch Autosport connectors, shrink boots and transitions, DR25, etc. Prices are hard to beat as well. If you don't see it on the website or it says out of stock, give Joe a call and he'll hook you up.

If you need any of the stock Mazda connectors, we keep a lot of those in stock.

I don't even use electrical tape to bundle wires for a harness. Leaves too much residue and bulks up under the shrink. I use Kapton tape. Holds well and leaves no residue.

Here is a good write up on harness construction. http://www.rbracing-rsr.com/sq6wiringloom.html

Big BUCKS is an understatement!

I think this is major overkill for most hobbyist, and above and beyond Fendamonkey had in mind?


-Ted

I can see this thread turning to shit faster than the A typical Microwreck instal with scotch locks!

Agree's fuck that! no need for anything more than some scotch locks, soldering iron and a Microwreck and some 5$ spark plugs and dildo coils of some V8 kuuunts from a forum univeristy site LOL using 16 ECU's in the wrong mode to control an air o plane jelly submarine car.

Australias #1 LOL Good enough for 8's good enough for Formula 1 :biggthumpup: :18: :Chevy_anim: :tongue1: :cheers2:

:hat:

All could have been done with some scotch locks and a soldering iron :biggrinjester: WINNING

(rbracing)So Bob is a friend of mine, he lists some cool stuff on his site and he has done more then any of the pretenders on the internest can dream about, inc racing at Le-Mans. We are both Pectel ECU runners ;)

I agree with Ted though, some of the stuff seen there is just way over the top and nothing to do with this poor blokes thread.

Lets face it who the fuck has $25,000 worth of electronics in their cars? let alone $5,000 worth of wiring and connectors @ cost price.

LOTS of good wiring can be done for a fraction of the price and no need to go to Raychem boots or DR heat shrink etc etc etc ....... :lol:

And fuck me all jesting aside there is nothing wrong with soldering so long as you know how to fucking use one! :nopity:

Once good set of wire strippers, a few good crimping tools, some Deutsch connectors, some heat shrink, some braided conjuit and you can make a nice harness for a fraction of the dildo spec NASA race team spec

http://www.rywire.com/catalog/images..._big/base1.jpg

I think people just get way carried away with this must be Autosport connectors, cryton dildo tape, mil spec tefzel wire, fucken DCM crimpers blah blah blah blah................ nice if you are rich but not everyone is, so no need to say this is what it is and the rest is shit.

There is stuff you can do for a 1/10th of the price and for the layman hobbiest its going to last you a fucking life time!

p.s. everyone knows scotch locks and microtech and BDC are CUUUUNTS!......... just trying to fire up the discussion :)

from $3k+ and several month harness builds, to scotch locks, this thread covers it all.

For Autosport connecorts
AS series high density micro sized pins I can tell you that soldering them is fine and in some cases prefereable to crimpind with DCM crimpers (which I also have).

Soldering them correctly though is hard and technically its a monkey ability job to do it with the correct DCM mandrel/positioner, but can still be fucked up.

The soldering method needs a jig and angle plate, a fine tip, but the result is amazing and will pass an flexture test and tensile tests and the wire will fail well past anywhere to do with the solder joint! I know I have tested it!

The beauty of the soldering as the pins are very expensive is you can reuse them if need be! not that this is a big point if you can afford the item that these connect too LOL let alone the connectors ! but I prefer this method as the joint is PERFECTION and its sealed and it will not oxidize over time, and its a perfect joint, and it is reuable, and its smooth, and the pin is not work harndened, and its the best joint despite what is written in the Duetsch manual about not soldering them!

That is my expereince, I have done thousands of these joints and never had a problem!

Nothing wrong with soldering, but its operator skill, where as with crimpers any fuckwit can use them and do an accpetable job so long as they are calibrated and tested to conform to the correct level of crush for the gauge of wire you are inserting in the pin!

Soldering is a good option.

Bring on the hate mail!

The classic irony of the anti soldering brigade is that on the other side of you mega dollar autosport connector its fucking soldered to the board of my $15,000 ECU LOL as it is in every single F1 car! and its all done by hand by a human with a soldering iron :)

It is totally fine to do it to a wiring harness so long as the joint is then supported against vibration and stresses and strains, this is common sense, glue type heat shrink you will see used by lots of people to reinforce these sodlered joints.

I've even repaired thermocouples and resoldered the wires back on past the Inconel sheilds then siliconed the joint then used simple heat shrink and these last longer than the fancy coiled wired strain reliefes.......... allot of this is common sense and its easy to use cheap and easily available products to ensure you have a reliable wiring solution without resorting to holding up the local 7-11 store to fund your purchse of XYZ dildo race car NASA spec Internet recommended brands.

FFS just look at how planes were wired in WW2 or how race cars won LeMans, they did all of this before XYZ "best practise" was pushed down your throat by layman 'experts' ................ its just pure common sense, problem is in the internet dildo phone youtube age its no longer common ;)

Sooo yes or no to scotch locks?

I'm with you on soldering. Personally I will solder just about anything if I have the time, and am at my workstation. If I'm not or I don't, then I'm going to crimp.

I've also basically been soldering since my balls dropped, and fear almost no soldering task. 0402 (metric... 0402 standard is no big deal) is something I don't really look forward to, but that's really about it.

I don't have a $4,000 professional soldering station, but I'm not exactly using a radio shack pencil either. I use a temp controlled 5 wire with Hakko element on a box that also has a hot air rework gun and a decent adjustable bench power supply.

Some of the most important things that I can tell soldering noobs are as such:

1) Large or small, there is no job that the correct soldering tip is a pointy cone. Chisel, and angle cut cylindrical are my favorites. I also make a lot of my own tips to maximize contact area and heat transfer for specific shapes of components. The contact area for heat transfer, and the mass for heat capacity are the largest factors in tip selection.

2) Too much solder is a BAD thing in pretty much every way. It makes the joint bulky, hard to heat, and is likely just masking a cold joint. If you find yourself having to use a lot of solder to complete joints, then see item 3. You are likely needing to use so much solder to get enough flux to finally clean the contacts so that the solder can spread. Flux is what makes the solder wick through the wires. Also note that sometimes wicking is something you want to fight, especially in automotive use. You don't want it to wick up the wire creating a hard flex point where the wire will fail in time due to vibration.

3) CLEAN surfaces solder well. The tip as well as the prepped surfaces should both be clean. Flux as needed where appropriate. If the tip of your soldering iron only seems to melt solder at a very specific point, and the solder beads up on it like a waxed car in the rain, then you have work to do. Sometimes the only way to recover a tip like this is to file off the surface, and tin it *immediately*. Treat your tips with care.

4) Use small diameter multicore flux or rosin core solder. Only use large diameter solder for very large jobs.

5) If you're even going to CONSIDER soldering on your car, buy a Hakko FX-888 or similar, and practice for a very long time. Just do it. You will regret not getting a real soldering iron with temp control that actually heats up and reacts quickly.

Still, despite having just said all of that. I generally recommend you just crimp your harness. Unless you have some other need or desire to learn how to perform very high quality soldering, it'd be a waste of time. Crimping works great and is retard repeatable.

I may put together another set of tips specific to automotive soldering such as how to solder to specific pins, how to solder crimp connections, how to support and protect your work, etc.

:rofl:

I wanna see I wanna see!!!

:smilielol5: Cheers!

I've come across a few of your harnesses @ S1, nicely done.... the only problem I had was with JRP installed it and picked the wrong wire for the IGN hot... nightmare chasing that one... :banghead:

I yes... forgot the shielded wire... if it's not already in the flying loom, Pacific coast Avionics is where I buy all my 2-4 core shielded wire...

I love Joe, he's awesome

Truff... you've hooked me up a few times when I've needed them...

I use it by taping the tape to itself so it doesn't transfer any adhesive... and I take it out of the harness before shrinking it....

:rofl:

Levi just wants to be baller ;)

There's no need for raychem boots, the same can be accomplised with some good 4:1 adhesive shrink and a pair of needle nose pliers.... but they look so damn nice....

And I am not the best, hence I ALWAYS crimp... don't want to chance a cold joint....

I love the connectors I put on the firewall... makes things much easier for me.... and they look pretty as well ;)

The last time I clocked myself installing a halltech, it was 27 or 28 hours to wire EVERYTHING including the stock dash, turning the overheat exhaust into a check engine light etc etc etc.... several months?

MOTHERFUCKING THAT

For the right person... I would rather crimp, quicker and less chance of a fuck up....

Again, goes towards the level of the user....

I just hatre layman bdc fagwadwhore selfproclaimed non loosers....

I still haven't redone the solder repair job on my 8... it's on the list but not a priority because I know it will hold just fine ;)

Because this is so important it deserves it's own post.....

the big thing is, there should be zero debate on soldering vs crimping when talking about engine harnesses because at no point in the harness should there be a splice of any kind.

Think about that.... Crimp the pin for the connector for whatever injector, coil, MAP sensor, TPS, whatever and it should be ONE SOLID LENGTH OF WIRE to either the bulkhead connector or the ECU..... the only place splices should exist is right off the ECU when branching out from say a relay or a fuse to 4 seperate wire for each injector....

Lets put it this way.... I've got like 12 hours into the harness for the 'vert.... this is after getting the PS2000 with the long harness (bought the whole thing used and the only thing altered was one of the trigger wires removed which I was fine with becuase FFE kit) and setting up the harness to power everything individually, splitting the grnd wires the, shields etc etc etc... I haven't even fit it into the car or started weith the engine side of the harness... it's like 8 feet of wire leading to a bulkhead and that's it.... soooo yea.... sooo much prep goes into a harness, most people just dont get it... remember... I've done more than a few of these and the last faily simple one took like 28 hours....

I can solder everything you just said you'd crimp.

Splices and butts aren't the only things that can be soldered.

Then again... when I solder to a crimp connector, it's after I've crimped it. ;)

As for splitting something off a relay to multiple destinations... don't they make bus bars, terminal blocks, and other things for that? Do it the right way, man, for god sakes! Do you not care about the children!?

fuck the children... I've done the busbar route and no thanks... to bulky. I will use power posts for 8ga and larger when needed.

I would rather take a 14-18 gage wire coming from a relay and use a stepdown connector to splice to 4 20-18ga wires to power things like inj and coils...

Sir Mix-A-Lot