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PWM constants question


midnightzxt

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I'm confused on the constants. I have a set of low impedance injectors in the car. These injectors are on the resistor setup like the installation shows. Now, in the constants page on the installation guide, it says to set the PWM to 100% and 25.5 ms as if they were high impedence injectors. Why is this? If you install the flyback board, which is generally the same thing as the resistors? you set the PWM to 30% and 1 ms. Lastly, low impedence injectors according to the MS manual tuning guide, is supposed to be set to 75% and 1 ms and tuned from there.

 

What is going on here? and what should I do?

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well, once again I can answer my own question: I'm an idiot :D

 

Injectors are either high impedance or low impedance. High impedance injectors (usually about 12-16 ohms) can take a 12 supply directly, without a form of current control. Low impedance injectors (generally below 3 ohms) require some form of current limiting. With MegaSquirt, you can use resistors to limit current, OOOOORRRRRR (*ding ding ding casino sounds*) you can use Pulse Width Modulation (PWM), which is a software solution built in to MegaSquirt.

 

Well, since I've got resistors, I can treat the PWM as I would a High impedence injector at 100% and 25.4 ms. Lucky me... Now if I could get the car start to acutally try this...:(

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