Can someone enilghten me on injector duty cycle? From my last log I see that my injectors reach 24ms and I don't know what % this is. Is there a way to calculate the duty cycle from the time they stay open? How many ms would be 100% duty cycle? The injectors I use are Lucas 42.5Lb/Hr.
You need to know the period of the PWM to get the duty cycle in percent.
duty cycle/period = (24ms)/(?) = duty cylce %.
The period is the inverse of the PWM frequency. 1/Freq=period.
2000 Ford Focus SE
OK, anyone on Pulse Width Modulation for our PCMs? Does it change or is it a constant value?
The point at which your injectors go static is a function of RPMs. At lower RPMs you have more time to get fuel into the motor (and less likely to go static) than at high RPMs. The point at which injectors first go static at a given RPM is 120/RPM (or 120,000/RPM to get the answer directly in ms.) As an example, at 6000 RPM your injectors are static if they're open for 20 ms.
To see the duty cycle that you're running take your actual IPW and divide it by the number from the above calculation. For the duty cycle in %, multiply the final number by 100.
John
Thanks, John! I guess I will need 50lb injectorsor I can try to lean her out for now. I have another question- how can you pull out the AFR from the O2 voltage, even though it would be rough numbers?
Miko
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