Hi folks.
As ever MS has thrown up a few queries.
I'm running a ms1 v2.2 board. MSNS code high impedence injectors and wasted spark.
In the basic settings there are conflicting stories on the injector settings. They are as below when pressing F1 in megatune. At one point it says to use 75% for the PWM and later it says for high Impedence injectors to use 100%?????????

Choosing PWM Values for V2.2 Boards

When using a V2.2 MS board or a V1.01 with flyback mods, you will have to substantially increase the PWM Current Limit percentage from the above calculations. Typically you should start at 75% and work down from there. Leave the time threshold value at small values, around 1.0 ms! If you set it too high, you will melt your injectors.

With either setup, if you are converting an existing EFI system with resistor packs on P&H injectors, you can keep the resistor pack, and then you do not need the PWM mode, so set the current limit to 100%. If you get rid of the resistor pack, then you will need to turn on PWM current limiting.

PWM Time Threshold (ms)
When running peak and hold injectors, set this value to the time your injectors require full current. A typical value for the full-current time might be 1.0 ms. When the injector has received a full-current pulse of this duration, the signal is modulated at the lower current for the rest of the pulse.

PWM Current Limit (percent)
For high impedance injectors, set this value to 100%. For low impedance injectors, set this value to determine the hold current, as described above for your particular hardware.

So which is it?? Also in megamanual tuning it says

On the Settings/Constants page:
High impedance injectors can run on 12 Volts without problems. Low-inpedance injectors require some form of current limiting. MegaSquirt® has pulse width modulation to limit the current. You need to set the PWM parameters to match your injectors:

* If you are running high-impedance injectors (greater than 10 Ohms), then set the:
o PWM Time Threshold to 25.4 msec, and the
o PWM Current Limit (%) to 100%.
(The presence or absence of the active flyback circuit (v3) or flyback board (v2.2) doesn't matter for high impedance injectors.).

what have you all done and which is right??

My MS1 with no flyback ran a rover v8, low impedance injectors with PWM current @ 75% with additional resistors to protect the output circuit.

It now runs my 893 blade engine on high impedance injectors with 100% PWM.

If the output transistors start getting hot then you need reduce the PWM %.

Regards Mark

The quote below is correct for high impedance injectors and also for low impedance ones if you use series resistors.
My car has run for the last 2 years with these settings.
Paul.

quote:

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Originally posted by omega 24
* If you are running high-impedance injectors (greater than 10 Ohms), then set the:
o PWM Time Threshold to 25.4 msec, and the
o PWM Current Limit (%) to 100%.
(The presence or absence of the active flyback circuit (v3) or flyback board (v2.2) doesn't matter for high impedance injectors.).

what have you all done and which is right??

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