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Which rpm signal should I choose?

Posted: Tue Aug 20, 2013 3:33 am
by mike malli
Hi guys,
since I am new to this EFI stuff I have the first question for you guys. I have bought an MSII V3.0 kit which I am going build myself. But now I am not decided how to procede in the built because I do not know which rpm signal I should choose. I could use the coil signal or I could install a hall sensor on the crank. Which one is more reliable? I had no plans to control the ignition since I would like to learn to walk before I run with MS. If should ever choose to add the ignition control in the future, is it easy to reconfigure the board or is sort of a nono?

Regards

Mike

Re: Which rpm signal should I choose?

Posted: Tue Aug 20, 2013 6:25 am
by trakkies
A coil negative trigger is the easiest - but do check your ignition is suitable. However, you can fully populate your MS so you can change over to a VR sensor at a later date if you so decide. It's only a question of swapping some links.

I started off fuel only, then added mapped ignition (EDIS) at a later stage. IMHO a sensible way for a newbie as there's less to learn up about in one go.

Re: Which rpm signal should I choose?

Posted: Wed Aug 21, 2013 3:04 am
by mike malli
Mmmm, interesting. You mean I wack in all the components I have received? My ignition system is im my old /8 Mercedes from 1972. Apart from the contacts, which I have replaced with a Pertronix, it is stock.

Mike

Re: Which rpm signal should I choose?

Posted: Wed Aug 21, 2013 6:52 am
by DonTZ125
That's basically it. It takes less technical knowledge with fewer chances for error to build the entire kit and then add one or two jumpers, than to select which handful of over a hundred components could be left off (even using the instructions as a guide). Leave off the wrong component, and no matter which jumper you select, it just ain't gonna work ... :lol:

Re: Which rpm signal should I choose?

Posted: Thu Aug 22, 2013 3:00 am
by mike malli
OK guys, I'll go through the instructions again and put the whole lot in. In case of a question I will ask again if you don't mind :D . Thanks for the moral support, I still feel a bit shakey. I will keep you posted.
Oh, before I forget, is the ignition system good enough to trigger the MegaSquirt ECU?

Mike

Re: Which rpm signal should I choose?

Posted: Thu Aug 22, 2013 4:32 am
by DonTZ125
If I read your original post correctly and you have a points replacement system, then yes - coil negative triggering will work.

Re: Which rpm signal should I choose?

Posted: Thu Aug 22, 2013 4:40 am
by trakkies
mike malli wrote:OK guys, I'll go through the instructions again and put the whole lot in. In case of a question I will ask again if you don't mind :D . Thanks for the moral support, I still feel a bit shakey. I will keep you posted.
Oh, before I forget, is the ignition system good enough to trigger the MegaSquirt ECU?

Mike
It's how all the early factory EFI systems did it.