Megasquirt Support Forum (MSEXTRA)

Hi fellas.

I have an idea i wish to ask for advise about. I`m making a instrument panel with 2 flip switches with each and 2 gauges. Each flipswitch will ignite a diode to show power. One switch will give power to MS3Pro, gauges one diode. The other switch will turn on the other diode and also my ignition. The final solution hookup ide is not finished yet but i thought i`d see if this is a way to do it. There are two lines one red and one yellow just to separate them. I`m not very skilled with photoshop Also the fusebox is not thought through and not the fuses either.

Will this work and i suspect not, then why and how?


Fire at will

I think that will work, but I gotta ask... why? Why not just let MS enable the ignition along with the injectors and FP, when crank rotation is detected?

I got xdi2 ignition now that works flawlessly so am i bit reluctant to go all the way. I don`t understand how the coils work etc and reading is not helping me. If i go all MS then i`ll have one switch just for the MS on a 2amp fuse then rest for the other switch. They will say "Ignition" and "Intruments" and have the diode on when powered.

So the wiring itself will work. Proud

Thank you so much for chiming in. If you got any good suggestions then shoot again

While that would work, it's unnecessary. You can power both the MS and the ignition from one switch. If you're worried about power line noise from the ignition system affecting the MS (which is a valid concern), then you can simply use a relay near the ignition system to pull (fused) power from the battery.

however, the MS is capable of driving 3 coils in a wasted spark configuration (more in some cases), that will help cut down on overall system complexity, and make the overall system easier to tune without the need to swap back and forth between software to tune different aspects of the engine control. You can likely use the xdi's current trigger wheel to trigger the MS as well.

If You REALLY wanted to, through some creative circuitry you could have the MS trigger the xdi that would look like a crank trigger to the xdi unit, however, it sounds like this is likely beyond your current skill level, so we'll not get into that right now, and is something that I believe would only benefit those of us into electronics design to make something work that is a bit of a challenge, or not normal to do. ;)

Just for the sake of educating me, what does the VR sensor do? My thought is it just sent a signal (5v?) to the xdi. The signal is just a current pulse or am i far off? Now if i use the VR sensor from Clewett (don`t see why i can`t), hook that up to the MS, then is it possible to use one of the digital outputs of the MS to signal at crank? To be honest i find it strange that this isn`t done already. The VR sensor from Clewett is just a regular one that you can pick up anywhere?

Thank you for taking the time

Porsche930 wrote:Just for the sake of educating me, what does the VR sensor do? My thought is it just sent a signal (5v?) to the xdi. The signal is just a current pulse or am i far off? Now if i use the VR sensor from Clewett (don`t see why i can`t), hook that up to the MS, then is it possible to use one of the digital outputs of the MS to signal at crank? To be honest i find it strange that this isn`t done already. The VR sensor from Clewett is just a regular one that you can pick up anywhere?

Thank you for taking the time

The VR sensor on your XDI generates an A/C sine wave that the XDI uses for RPM input and TDC location. The signal increases in frequency and amplitude as engine speed increases. The MS can indeed use the VR sensor and wheel and for that matter the coils from the XDI system(with an ignition module like a quad spark). The sensor that Clewett sells however is only available from Electromotive dealers.