So im wiring up the msd box for my megasquirt setup in the duster. Im concerned about electromagnetic interference.
The signal wires from the distributor are sheilded.
All the megasquirt wiring is in its own seperate loom, but run next to the rest of the wiring.
The signal wire from the megasquirt is in the same loom as the switched 12v to the msd box and tachometer output wire.
Im worried about the coil wires causing interference. Do i use the pair that msd sent (not shielded, not twisted) attached to the box and run in the same loom with the rest of the msd wiring? Do i cut it off close to the box and run a twisted pair to the coil? Different but parallel looms?
Am i just overthinking this?
Any reason that you cant use it as is and change it later if there are issues?
In reply to wvumtnbkr :
None. Just trying to prevent issues
But probably actually causing them instead by overthinking it......
Coil power wires? Those should be fine since they don't have much for "signals". Just 12v and ground right?
Your coil to dist and plug wires should be shielded, but those are hard to mess up.
In reply to Robbie :
In theory yes just power and ground. However with the MSD being a capacitive discharge unit does that change things? It also supposedly puts out a lot more voltage and the amperage then a normal ignition system.
The high power should be in the spark plug wires only, everything on the hot side of the coil. I don't have direct experience with MSD systems but I can't imagine they would mess with the 12V side.
MSD systems run around -400 volts on one of the coil wires, but there still isn't a huge amount of RFI from the external wiring. Beyond ignition coils, non-resistor spark plugs (a HUGE offender!), and spark plug wires, RFI is not much of an issue. Most of your electrical noise problems in a typical car installation are from improper grounding or noise injected into the 12 volt feed wires, not from radiated noise.
Megasquirt only typically uses shielded wiring on Variable Reluctance or Hall Effect sensors. Even then, the 12v power and ground for those particular sensors is inside of the wire sheath with the signal wire, and sometimes inside of the shielding.
I wouldn't worry too much about it. Coils are definitely not a real cause for concern when it comes to shielding.
