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high impedence injectors and MS
omega0684 - 20/2/09 at 04:06 PM

i have high impedence injectors on my ITB's, the ms manual says

quote:

To tune the PWM [pulse width modulation] values for your engine, you need to know what kind of injectors you have: low impedance or high impedance.To tune the PWM [pulse width modulation] values for your engine, you need to know what kind of injectors you have: low impedance or high impedance.

If you are running high-impedance injectors (greater than 10 Ohms), then set the:
PWM Time Threshold to 25.4 msec, and the
PWM Current Limit (%) to 100%.
In essence you are disabling the PWM mode. This allows full voltage to the injectors throughout the pulse widths.




so does this mean i dont have to set the pulse width criteria because there is always 12v's on the injectors and they won't burn out cuz they are high impedence.

vinny1275 - 20/2/09 at 04:19 PM

Yeh, there's something different you have to do with the low-impedence ones, but if you have high-impedence you can just bung in the settings from the manual and forget about it....

Cheers


Vince

mark chandler - 20/2/09 at 04:40 PM

If you use car injectors these will tend to be 10ohm each, bikes are around 50ohm.

The output transistors on the MS standard board can run a pair of bike injectors without boiling up so a 25ohm load as parallel wired.

A pair of car injectors would be a 5ohm load which causes problems, MS deals with this by giving pulsing the current to the injector, so a long pulse to open it then lots of little pulse to hold it open, this effectively halves or quarters the load on the transistors, pretty clever really.

regards Mark