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

Hey everyone,

I am currently trying to run MS2 V3.57 SMD on a Yamaha C3 engine using the ignition module that came with the engine. The engine is a single cyclinder, 4 stroke and fuel injector. In order for direction ignition control, I have purchased the BIP373 and will be installing tomorrow. I have designed the wiring harness where the 12V supply to the ignition is picked off of the raw 12V power supply to the MS2 (with a 2 amp fuse just in case anything weird happens). Because the ignition system uses inductors, I am worried that during the dwell period the voltage may exceed 12V because of inductors relationship of di/dt = (1/L)*V. By looking at some of the electrical schematics of the MS2 PCB, there is a voltage regulator that clamps this input voltage. Should I include another voltage regulator on the raw 12V power supply to the MS2 just incase something funny happens or MS2 was designed for this sort of set up? Please help.

Nana

The coil connection on the BIP373 shouldn't be able to jump to the MS 12 volt plane.

For the V3.57 PCB, is it necessary to install the R43 resistor? Seems like there isn't a location to install this resister compared to the V3 PCB. Is it necessary for the V3.57 PCB if direct coil control is preferred? I am having troubling finding the pad to install this resistor.

Installing R43 on a V3.57 is neither necessary nor possible. It's just there for people who were testing dwell with an oscilloscope and did not have a current probe; this feature wasn't used very often so the V3.57 dropped it.