MicroSquirt.com read only forum (Jan.15,2018)

lance wrote:WOT,

The original poster was asking about not using the bypass relay (or another bypass signal). If you leave 5 Volts on the bypass pin at all times, then MS-II has control over the timing, even during cranking. By having it send a 'trigger return' output to the module, you get essentially the same timing as you would in bypass mode, but without the relay and without using up a processor output.

Lance.

Hi Lance
I was looking for old solutions in the web for 5v on bypass in HEI which I use. I have MS-II V2.36 and I wander if I must have constant 5v på bypass or it´s quit enough with the "trigger return" output and let the bypass pin alone.

thanks for help
m

m,

Unless the 7/8-pin HEI module sees 5V of the B pin, it uses the trigger directly.

So yes, you need to supply 5V to the B pin. If you are using trigger rise, you can supply 5V at all times, and not use a relay (you can also use one of the spare ports to trigger the 5V to the B pin).

So there's a number of ways to do it, but the bottom line is you need 5V to pin B whenever you want MegaSquirt to control the timing.

Lance.

lance wrote:m,

Unless the 7/8-pin HEI module sees 5V of the B pin, it uses the trigger directly.

So yes, you need to supply 5V to the B pin. If you are using trigger rise, you can supply 5V at all times, and not use a relay (you can also use one of the spare ports to trigger the 5V to the B pin).

So there's a number of ways to do it, but the bottom line is you need 5V to pin B whenever you want MegaSquirt to control the timing.

Lance.

Ahha.. so u mean I´ll supply 5v from MS Vref and set the cranking trigger på "trigger rise" not trigger return?

m