Wiring of your car.....????

OZCOBRA · #1 (**permalink**) 06-09-2003, 07:18 AM

I'm wondering just how many of you out there have tackled the job of wiring your own cars? With all the electronics now days how have you found it if you did it yourself ? Any suggestions for donor looms to modify to suit the cobra application(Motec m8 396 Windsor) or is it all to hard and start a fresh or seek a Pro.?????

750HP What did you do???Motec what do they supply?

Horse · #2 (**permalink**) 06-09-2003, 07:42 AM

well I have done a couple cars from the ground up , and while its hard, I also thikn that its not too bad, especially if you have someone who can cover your back, like Thomas does for me, but again, as long as you have all the wiring diagrams that you need and you feel like you can do it I say go for it, the satifaction alone is worth it!

OZCOBRA · #3 (**permalink**) 06-09-2003, 07:48 AM

Horse , Exactly what i was thinking ,hey it can't be that hard with the right equipment and advice and the satisfaction of knowing you did it !!! i couldn't agree more...!! Paul

John Poling · #4 (**permalink**) 06-09-2003, 11:07 AM

Paul,
Wiring is a cinch!!! I started with a universal Painless harness and modified it heavily from there. The single biggest problem with wiring is grounding, improper grounding is the most common problem with those so called electrical system "Gremlins". Most of it is common sense to me (but I am an electrical systems engineer at a large automotive OEM), the best thing for grounding an electrical system properly is to have as few grounding points as possible (one point is the best and is the way I set mine up). My suggestion would be to run at least a "0" gauge cable for your main ground terminal on the battery to your frame making sure that you have completely removed all foriegn matter first(paint, grease, rust etc...) use as large of a terminal end (frame side of cable) as you can find in your required length. From there figure out where you can locate a point where you could mount a junction block stud box that would be somewhere in the middle of all your componants. Run a single 8 or 10 gauge wire from the frame (pay attention to your prep work on the frame) to the block and use as large of eyelet you can and install it to your ground stud first. From that point, run all of your grounding wires to this single point not installing any more than 6-8 wires to each stud, if you need more grounds than this add another stud box running another 8 or 10 gauge wire from the frame to each additional ground block. Keep in mind that it will be easier to troubleshoot your system if you keep certain systems tied together (engine circuits togehther, lighting systems together, and dash wiring together) that way you can all but eliminate ground issues if only one item is acting up but not others that are tied to the same point. Don't forget to run a large ground strap between your engine block and the frame preferrably using the same ground stud on the frame that you used for the rest of your systems.

Spend a little bit ($10-$20) to save yourself from having nightmares later and buy a quality crimper from Radio Shack or someplace like that to do all of your crimping operations. A terminal that has been crimped using a cheapy crimper will work for a while but over time will fail long before the same crimp done using a quality crimper.

After you have bolted your grounding points to the frame for the last time, apply some type of sealing grease or compound to seal up the whole area of the grounding point, get sloppy if you need to but make sure that you have sealed the whole point so that contaminants of any kind can't get to the actual metal of the joint.

Sorry for the lecture but I wanted to get my point accross about how important grounding circuits are to the overal performance of a vehicles electrical system.

If you or anyone has any further questions of Electrical systems, just ask by posting here and I will try to answer to the best of my knowledge.

John

OZCOBRA · #5 (**permalink**) 06-10-2003, 04:48 AM

John,
My friend you've gone straight into my Buddy list with that sort of reply you'll be the first person i call , hopefully that won't be to often but be prepared!!!
What are your thoughts on soldering wire ends?Is it worth the time doing it,are there any negetives as i've always done this with car stereo gear?? What about liquid tape Y/N??
The first electrical tools i ever bought ,just happened to be a good quality crimper and wire cutter/stripper..!!!
One last question running the battery in the trunk what sort of main cable would you recommend running, i've heard people talking about interferance ,and protecting the source cable from it???

Again thanks for the Sterling reply
Regards Paul

trularin · #6 (**permalink**) 06-10-2003, 05:21 AM

Once you know the rules, just follow the wiring diagram.

And, if you do not have a diagram, take one from the thousands of manuals that exist.

Make a copy and get two highlighters. Once you have a circuit installed, highlight it as installed. Once you have check the circuit electrically, highlight it working.

It is not as bad as people think.

There is a guy on ebay that sells 20 feet of silicon jacketed 1/0 stranded cable for putting the battery in the trunk. works real well.

A test meter would be a good thing to get as well as a crimp tool and utility knife. The rest is toolbox stuff.

Worst case, ask here.

OZCOBRA · #7 (**permalink**) 06-10-2003, 05:38 AM

trularin,
Silccon 1/0 CHECK OK!! Multi Meter sorry i purchased that as well-a good one too....!! I've just got learn how to use it!!!

Highlighter plenty of those at work!!!Books ..... Well i've never read a book cover to cover unless it was a car magazine,...off to the book shop i go!!! any toubles LOG onto CC Done

well i'm set thanks again........ Paul

John Poling · #8 (**permalink**) 06-10-2003, 05:39 AM

Paul,

Soldering is in my opinion the absolute best as long as you know how to solder properly and not overheat the wire, overheating will make the wire brittle and it will break a lot easier. What I did on mine was not the soldering route but regular crimping with a top-o-the-line crimper and then used a heat shrink-able tube with a "heat activated" glue inside so that when you heat it up with a heat gun to shrink the tube over the wire/terminal joint it also seals out the environment so that nothing can get into the joint to cause corrosion. An added benefit of the heat shrink is also that it will give you a strain relief on the joint it is applied to so that the wire will not pull out of the terminal you crimped on.

I don't have experience with liquid tape although I have heard of it. I would suggest the heat shrink over anything else. You should be able to pick it up at an automotive or home electrical supply store. I just realized you're in Australia so I don't know how to help you on where to find it or if it is even available there. I know it is plenty available in the U.S..

Running your battery in your trunk is fine and I would recommend a "00" gauge cable for both negative and positive, I would also recommend if you have access to a solder pot to solder dip the terminals on the opposite end of the actual battery connections onto the cable and heat shrink them as well. As far as Electro Magnetic Interference (EMI), you probably won't have an issue with this as you should run your positive battery cable on the frame under the car and the rest of your wiring should be no where near the main positive battery cable to cause this. Just remeber that this cable is the supply chain of your whole electrical system and if you decide to use your frame as the main ground that it is in fact the ground, therefore make sure that you use a heavily insulated cable clamp to route your positive cable on the frame rail.

With wiring on a car, remember that everything has to have a good positve feed and a better ground otherwise your components will not be reliable.

Any other questions? Just ask.

John

OZCOBRA · #9 (**permalink**) 06-10-2003, 06:09 AM

John,
I'm a big fan of the Heat Shrink Tube, i love the stuff.
As for the main cable not a prob. will do!!! Good access to all things electrical so no problems getting stuff as long as i know what to ask for.
Cheers Mate thanks again for your time,
Regards Paul

750hp · #10 (**permalink**) 06-10-2003, 06:17 AM

Paul,
From the outset, I decided that if others could do better work on my car than I could, and the price was reasonable, then I'd let them at it. While I might not be able to say that I did it all with my own two hands, at least everything should be done right the first time.
Wiring was a case in point. For the thousands of dollars that I had invested in the M800 Motec, multiple temp sensors, hall effect sensors, magnetic pickup sensors, multiple pressure sensors, MSD Digital 6, HVC coil, gauges and senders, there was no way that I felt comfortable with risking it all to save $900- for a custom engine loom made from MilSpec wires, correct shielded cable, Raychem heatshield, gold pins for the M800, and all wires labelled. This runs through a MilSpec Connector at the firewall so that with a 1/4 twist of the connector, my entire engine loom can be taken from the car still attached to the engine. It's interesting to note that no MilSpec wires that I've ever seen have been soldered. They are all crimped using a $$$pecial crimping tool.

I might have done some study and gone ahead and done the rest of the car, as that all seems a lot less important to me than the ECU harness. To be honest, for the extra money I couldn't see why not to let the one guy do the whole car. That way, if there are ever any wiring problems, the car goes back to him and it's all fixed!

Here's a 100K photo of most of my wiring:
http://www.home.gil.com.au/~marsh/motecwiring.jpg

OZCOBRA · #11 (**permalink**) 06-11-2003, 07:01 AM

Craig, what was the time frame for your wiring and did they stick with the quoted time and dollars ?...was it a prof. friend or a sourced tradey...?was the Milspec stuff easily obtainable or a special order????I've heard some shocking stories relating to excessive times upto 4 months in one case and $1800.00 just for the loom without inst.(Painless Wiring) ....Paul

Art Burtt · #12 (**permalink**) 06-11-2003, 08:00 AM

One suggestion,if you have a mechanical speedometer . Don't wire it like it was an electric one. This causes blown fuses and many hairs to be pulled out! Duh??? Been there done that!!

Tinker51 · #13 (**permalink**) 06-11-2003, 09:36 AM

Paul,
making your own loom is really not that bad, just time consuming. A friend and I rewired his car after a ground up restoration. Granted this was a low tech car with no EFI or any other electric engine controls (we did install an MSD) but it was not hard. We took a big piece of paper (poster size) and in one corner listed all the electric components in the car then started drawing out a diagram and checking off components as we went. When we were satisfied it was right we set up a 4'x8' sheet of styrafoam (spelling?) and began laying out wire. We crimped, soldered and put heat shrink tubing on all ends. We used a light blue color of heat shrink and wrote in black marker what the circuit was as it entered the terminal/fuse block. When it was done we removed all fuses from the block, hooked up the battery and waited a few minutes looking for smoke, then we would put one fuse in at a time and try that system. It worked perfectly and has been no trouble since. As I said, not hard or technically difficult, just time consuming.

John Poling · #14 (**permalink**) 06-11-2003, 10:31 AM

Careful, you don't want to let the smoke out of a wire, once you do it probably won't work again.

Mr.Fixit · #15 (**permalink**) 06-11-2003, 10:43 AM

That's known as the "Magic smoke" once you let it out, there goes the magic

Tinker51 · #16 (**permalink**) 06-11-2003, 08:09 PM

A friend had a Triumph Spitfire that ran because there was smoke inside the wires. She knew this to be true because while driving (on more than one occaision) if a puff of smoke came from under the dash the car would stop running. Thank you Mr. Lucas, Prince of darkness. Why do the British drink warm beer? Lucas refrigerators. Why don't the British make computers? They can't figure out how to make them leak oil.

750hp · #17 (**permalink**) 06-12-2003, 05:41 AM

Quote:

Originally posted by OZCOBRA

Craig, what was the time frame for your wiring and did they stick with the quoted time and dollars ?...was it a prof. friend or a sourced tradey...?was the Milspec stuff easily obtainable or a special order????I've heard some shocking stories relating to excessive times upto 4 months in one case and $1800.00 just for the loom without inst.(Painless Wiring) ....Paul

Paul, when I mentioned $900- before, that included the MilSpec wires, heatshielding, some sensors, wiring plugs etc. The labour component of the Motec loom ran to about $200- from memory. The guy I used is an "Authorised Motec Installer" up here in Brisbane. I think he did me a killer deal on the engine loom because he knew that he'd get a bit of business once my car was finished. He got a bit slack with a couple of things relating to the standard vehicle loom, but that's the beauty of paying someone else to do the wiring - they fix any mistakes for free!!!

The engine loom took 4 days to complete. He didn't have the car during that time, but simply needed to know the distance from the back of the motor to the MilSpec plug. The MilSpec wires that he uses come in a massive roll (300-400 metres at a guess). The connectors are always in stock. I think OZVENOM has since found a cheaper supplier for connectors, but I can't remember if they're the AeroSpec or MilSpec. The military specify a higher temperature rating and use exclusively gold pins. And they're a nice green colour....

Speaking of excessive quotes - Motec suggested I speak to three different wiring guys in Qld. For a COMPLETE wiring job, including the M800 and all sensors, then all the vehicle wiring, one quoted $2500, one $4500, and one $7500. What are they thinking??????

OZCOBRA · #18 (**permalink**) 06-12-2003, 06:23 AM

Craig , I think i'll grab you for a week to do some consultancy work for me ,these deals and people you seem to find are to be envyed....i'll definitly be giving you a call for the motec pretty soon...!! the auto elec's i've spoken to have wanted the car for anything from 2 to 6 weeks and even then they gave the impression that was a give or take estimate....Paul

MAGIC SMOKE Hey, ac andy will chime in soon its another chapter to the cookie saga

ac andy · #19 (**permalink**) 06-12-2003, 08:14 AM

You are onto some serious s#*t Paul with you cookies and magic smoke. Next you are going to want to know who has a paddock full of magic mushrooms!

EA - EF Falcon wiring loom for the majority of the car. Simple, easy to use and has all the Ford plugs on it. Around $100.00 to buy.

Andy.

trularin · #20 (**permalink**) 06-12-2003, 08:31 AM

OZCOBRA,

Hey if you would like some copies of prints of 1964 to 1974 Ford wiring, let me know. They are not very good for printing, but they will let you know how something was wired back then.

Just an offer.