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ECUMASTER PMU and kill switch

EFI Wiring Fundamentals

Discussion and questions related to the course EFI Wiring Fundamentals

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Hi all,

I have a case where a PMU will be used together with a red key mechanical isolation switch.

I understand that one way to get these to work together will be to have the isolation switch just after the battery before the PMU and to avoid the alternator continuing to power the car use another wire to the smaller terminals on the isolation switch to a input on the PMU to giving a signal to switch off the coils. This seems rather elegant, but what about the load dump from the alternator?

This is an older car, so it is on transistor ignition and a distributor as well as carburettors

Thanks in advance for your answers

With a mechanical kill switch I don't know if there is an easy way to get around the load dump from the alternator, however at the same time these kill switches have been used for decades with little trouble. The only other option for peace of mind would be an electronic kill switch which can provide a engine shut off signal slightly before disconnecting the main power feed.

Thanks Andre!

Normally you would place a resistor so that it gets in contact with ground only when the switch is turned off to get ris of the load dump this but it appears difficult with the PMU.

Do you think there is a real risk of damaging items like instruments or the PMU without such a solution?

Hello there,

Since this is a very relative (and quite new) topic to my question, i dont know if I should create a new topic.

Admin please feel free to correct me.

My question is as follows. I am wiring a race car (club level) and an ECUMASTER PMU will be used.

Can I use the 12SW pin as a kill switch or use one of the inputs as a kill switch? That is because I need the car to have no power at all with a switch from the outside. Sorry if this question seems very low level.

I am pretty confident that the PMU is able to handle the load dump from the alternator.

Kind Regards.

Take a look at this Youtube video where Motec discusses this topic. [url=]