The smallest wire my hardware sells is 14-gauge. Which is clearly too large, i'm not sure exactly which gauge i should be using, or what kinda jacket the wire needs. Any help?
The size of the wire depends on what size fuse protects the circuit. What are you installing the wire for, and are you planning to splice it into an existing circuit or are you planning to install a dedicated fuse for it?
Wiring a full 3800 harness up to the c203,c500,BCM and engine. All the wire seems to be the same gauge to me, but i'm not an expert. I plan to pull every pin and resolder every wire or buy new pins/terminals where necessary.
If you're building your own harness, then you really should get a manual which shows you the size of the wires used in the stock configuration. While some people use just any old wire they can come across, the gauge of the wire is chosen to support the amount of electrical current (amperage) of the total current draw on any given branch of a circuit. If you over-size the wire, there aren't any problems except that it's harder to work with and can add more than a few pounds to your car. If you under-size the wire, you risk melting the insulation and having shorts and even fires.
Here's an example of a typical wire diagram:
The number just before the color of the wire (for example "1 ORN" at the top) indicates the gauge of the wire that's used in metric. A 1.0 is equivalent to 16 AWG. All of the wire diagrams show several different wire gauges throughout. You can't always judge the gauge of the wire by looking at it's outside diameter since different insulation materials and thicknesses are often used. If it helps, here is a conversion chart from metric to AWG sizes:
If I were you, I'd switch from the hardware store to an autoparts store for wire in small lots. My local NAPA carries some sizes, but it would be pricey if you had to make long runs.
FWIW, I buy automotive wire from wiringproducts.com - they have good quality wiring at reasonable prices. If you need a lot, I'd recommend waytekwire.com as they're a pleasure to deal with.
I'll also throw this out: Go to the junkyard with a big ol' bolt cutter and find a couple cars that have had interiors pulled and then chop the harness that runs the length of the car, like down the center tunnel or the sill. You get nice ~6' lengths of wire in lots of pretty colors that you know is automotive grade. Sometimes you can ID cars that have similar runs across the radiator crossmember or down a fender, too. I've made some really nice replacement wiring harnesses this way, like a new fuse box for my '62 Falcon:
The number just before the color of the wire (for example "1 ORN" at the top) indicates the gauge of the wire that's used in metric. A 1.0 is equivalent to 16 AWG. All of the wire diagrams show several different wire gauges throughout. You can't always judge the gauge of the wire by looking at it's outside diameter since different insulation materials and thicknesses are often used. If it helps, here is a conversion chart from metric to AWG sizes:
Very useful information! I hadn't realized that the wire gauge was in the diagrams.
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Originally posted by thesameguy:
FWIW, I buy automotive wire from wiringproducts.com - they have good quality wiring at reasonable prices. If you need a lot, I'd recommend waytekwire.com as they're a pleasure to deal with.
I'll also throw this out: Go to the junkyard with a big ol' bolt cutter and find a couple cars that have had interiors pulled and then chop the harness that runs the length of the car, like down the center tunnel or the sill. You get nice ~6' lengths of wire in lots of pretty colors that you know is automotive grade. Sometimes you can ID cars that have similar runs across the radiator crossmember or down a fender, too. I've made some really nice replacement wiring harnesses this way, like a new fuse box for my '62 Falcon:
That really is the best/cheapest way to get a lot of good wire wire in a variety of jacket colors and stripes, without having to buy a bunch of large rolls. The interior harness tends to be uncorroded and long. Engine harnesses are not good to harvest from, because the wire insulation is usually degraded due to exposure to high temperatures, and the wires can be corroded from the terminals to a few inches down, even under the insulation.
I can also recommend Waytek Wire as a great source. Good customer service, good prices, and a wide selection. Some components are only available in large quantities though.
I found this place recently as well: http://www.genuinedealz.com/ They mainly sell marine wiring stuff, so it's a good source for adhesive-lined heat shrink tubing, bus bars, covered fuse blocks, etc.
[This message has been edited by Steven Snyder (edited 11-20-2013).]
It is a mistake to use anything but cross-linked polyethylene underhood, especially with a 3800 in a Fiero. Cheap hardware store wire is a fire hazard. PVC automotive wire is less than acceptable.
Originally posted by Steven Snyder: I found this place recently as well: http://www.genuinedealz.com/ They mainly sell marine wiring stuff, so it's a good source for adhesive-lined heat shrink tubing, bus bars, covered fuse blocks, etc.
Thanks for that! I just bought a big QuickCable battery cable crimper (tired of my "hammer based" crimper fer realz) but the place I bought it from doesn't stock adhesive heat shrink... And, that reminds me - www.remybattery.com has, as you would expect, a lot of battery cable and some miscellaneous wiring supplies, and they're also nice to deal with. Bought the crimper and the QuickCable lugs there.
Originally posted by fisherlr777: The smallest wire my hardware sells is 14-gauge. Which is clearly too large, i'm not sure exactly which gauge i should be using, or what kinda jacket the wire needs. Any help?
Insulation needs higher temp plastic that resist oil etc. Many "off the self" wire at parts stores and others won't last long in engine bay.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
The wiring used in the interior of the car is not suitible for the temperature under the hood. Also, the engine harness and the interior harness do not share a lot of the colors/gages.
Go to the wrecking yard and choose about any GM car and chop out the engine wiring harness.
There is absolutely no problem with properly splicing and insulating wires rather than using new wire/pins.
Your approach may be good for saying "My harness is all new", but the finished product will not perform any better than a harness that is constructed from donor underhood harnesses using proper splicing techniques.
Go to your local junk yard, tell them what your doing and ask if you can just buy a few feet of wiring harness. 5-10 min and some bolt cutters and you'll have plenty of super high quality wire. most yards will have a bin full of misc. harness $20 should get you more than enough wire and it will be MUCH better quality than anything form a hardware store and you'll have many different colors .
Radio Shack sells just about every wire size insulation you could want in rolls so you just need to buy the right colors for the right gauge wires. and there are a few different ones depending as others have said on what is going threw them. your local store might not have all the right ones but they can, or you can get them threw them.
Steve
------------------ Technology is great when it works, and one big pain in the ass when it doesn't
Originally posted by olejoedad:The wiring used in the interior of the car is not suitible for the temperature under the hood. Also, the engine harness and the interior harness do not share a lot of the colors/gages.
About all that Radio Shack now sells thats usefull is the wire. The interior wiring from a junked car is a good cheap source...just do the yard a favor and dont cut them out of a car with a good floor and rear section. I hated buying a used rear or front clip WITH the wiring included, to find out some azz ripped out all the wires and I had to spend a day or two making up a whole new set for free. I dont know how many times I bought a used door where the wiring connector was cut off with bolt cutters only inches from where it unplugged. Why not just unplug it and save me a day of handwiring a door.
I've never understood pointless junkyard destruction - if the choice is a couple hours of dismantling or violence, I can understand the quandary, but if it's the same amount of work and one path doesn't screw the next guy, why not be courteous?
Years ago I spent hours taking a transmission out of a car and because I try to be courteous each sub-assembly I removed I put in the trunk, doing my best to contain relevant hardware nearby. The wiring harness was unplugged and coiled up in the back seat. About two weeks later on a forum I frequent someone posted a message saying "Whoever dismantled this junkyard car, thank you" with the details inside. We had a good laugh and two people got to go home happy from the junkyard. Good times.
No, it is not. You are incorrect. The answer is specific to the Fiero and other GM car harnesses. I have built several harnesses for Fiero swaps, as well as harnesses for other vehicles. The interior wiring insulation is not suitable for use in the engine compartment. It does not have the temperature range neccesary for the environment. The engine wiring also has several color combinations that do not appear in the interior harnesses.
When building a harness it makes a lot of sense to follow the wiring color codes used by GM. Later troubleshooting is a lot easier when each wire can be recognized by color code.
To add to your point. There are also different grades of loom. Some are for general electrical, others are heat rated for underhood. Putting interior rated loom under the hood is a bad idea. It melts.
While it may make sense to use GM wiring for such a project, nowhere in my post did i suggest sourcing the wire from a GM vehicle. I can't say whether it's true that GM uses different wiring underhood than in the passenger compartment, but that is atypical and certainly untrue of every other car I own which, at the moment, comprises eight models from six non-GM brands. It may be true of GM, but it's not true of Saab (pre GM, for clarity), Audi, Jaguar, Ford, Volvo, or Toyota. So, my statement stands that claiming inside wiring is different than underhood wiring is different is an inaccurate generalization. GM practices != all manufacturer practices. I can't even find a single reference to the notion via Google, so I question whether it's true at all. I'd be very interested to know more about this, so any links you can provide would be helpful.
GM switched to cross linked insulation around 1990. The stuff they used in 80s cars (including the Fiero engine harness) is a lower grade than what you want to run in a 3800 Fiero.
