Megasquirt Grounding Questions.

[LowR3V'in]

On top of the stock trunk ground strap
I ran a cable to a lug in the engine bay
so I can directly ground my logic level coils.

My question is,
I have enough wire to making another ground.
Should I run that to the factory ecu ground location on the strut?
Or would that put some noise in there or something like that?

I'm thinking of running it to the other strut studs or maybe directly to
the block using a motor mount..

Easy question but I'm an electrical noob.:puppy:


Here is the lug. It's inside the wiring cover.

[blueapplesoda]

you don't need to run the wire from the trunk ground to the ms unit...

Use the factory ground point for the ECU, which is the same for the engine harness (shock tower/battery tray for m20i, and glove box roof for s14/m20e).

Ideally, your factory engine harness (if you are using a stock one) has all the proper grounds already placed in them. Browns are chassis, and br/or are sensor grounds (ecu first, then to chassis).

Derek
DedericMS

[LowR3V'in]

Hey Derek.
Yeah but since I got another ground cable I can use,
maybe I can run it somewhere for a better ground in general.

idk, maybe to the block or maybe that's just a bad idea. idk.

The directions says to ground directly to batt. so I made a ground for it.

These things have allot of ground.
Another for cyl head, another for the ecu grounds.

http://www.aemelectronics.com/high-output-igbt-inductive-smart-coil-1240

PINOUT
A: Coil Trigger (0-5V signal)
B: Coil Trigger (Ref Ground)
C: Ground to Cylinder Head
D: Battery Ground
E: Battery Positive (Relay or switched ignition)

[blueapplesoda]

My bad, I misread your question. It wouldn't hurt it. The only time I see ground differentials is when the sensor grounds are grounded all over the chassis/engine like they were on older cars. Tying the actual battery negative to the strut tower isn't going to cause any problems like that, it would just be somewhat redundant.

If I were wiring it, I would do it like this:
(B) same ground as the ecu ground is a must
(C) and (D) are not as important where, as long as it is a good solid ground.
ie. I would wire them together and ground them on the cylinder head if I were mounting my coils on the VC, or on the strut lug if I was going to mount the coils on the chassis.

In your case (C) and (D) can be tied to that lug you made.