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 -