Gauge Questions

Mikey · #1 January 21st 2007, 04:25

I read another thread about this, but I'm still wondering. I'm close to the finish of my Ghia. Well, close enough to start planning for the harness. Since I'm going Subaru, I'll have a computer. The computer needs a power from the front along with all my gauges need signal wires. A total of about 10-12 wires, give or take a few. I ran a second peice of conduit on the driver's side heater channel.

My main question is this, Will I have problems with the power wires and the signal wires next to each other. And, is there anything I can to avoid it if I do?

Also, will the differant signal wires mess with each other? I have 5 signal wires, will they not read right if I put them all next to each other?

Thanks,

ricola · #2 January 21st 2007, 06:18

It is always good practice to keep power and signal wires away from each other, particularly in Audio installs. Is your battery going to be up front? The main ones that are at risk are the crank/cam signals but these are shielded in the subaru loom so as long as this is kept you should be OK (I presume the ECU would be in the back anyway)
Rich

**NO_H2O** · #3 January 21st 2007, 09:33

Iduction is more of a problem with A/C power (that is why alternator noise is a bitch to keep out of you audio signal). Low DC power (12v) doesn't give you as much trouble until you start getting into higher current and pulsating current (that is why there is no such thing as a DC transformer). Sheilded wire will take care of most induction problems as long as the sheild is grounded at one end to give stray voltage a path to ground.

yetibone · #4 January 21st 2007, 10:56

I'd imagine that the tach signal, CHT, and EGT wires would be the most susceptible to induction interference, and the ones to isolate (shield) since the tach signal is a pulse, and CHT and EGT are such a low voltage signal, but you prolly won't have any trouble running them all together in one bundle. If you put the battery in the front, just don't run your gauge wires along the main battery cable.

I'd actually planned to run mine in another loom along the existing harness, unless I see the gauges doing wacky things...then I'll try to shield the offended wires from the ones doing the offending.

Mikey · #5 January 21st 2007, 17:17

Thanks for the replies. I realize now I didn't include many details.

The battery will be in the stock location, the computer will be in the driver's side battery location. I'm not using the Subaru ECU, I'm going with Megasquirt. From what I've read so far, the computer needs power when the key is turned on and when the starter is going. So I have to run the wires to the front. I completly forgot about audio signals too.

So, I have CHT, Water Temp, Oil Temp, Tach, Oil Press. I can run these singal wires together in their own loom, I just have to sheild them away from the power wires?

I'm needing some sheilding anyway. Where can I get some for this too?

yetibone · #6 January 21st 2007, 17:35

CHT and tach signal may need shielding, but all of them can run in one loom.

Aircraft Spruce sells shielded wire in 10' lengths.
http://www.aircraftspruce.com/catalo...shieldwire.php

Mikey · #7 January 21st 2007, 17:43

Thanks yeti, I had this website. But I forgot about it until I saw a picture of that sheilding.

http://www.rs-autosport.net/catalog/...roducts_id=222

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