But the magnetic field is controlled by the duty cycle of the 12V signal to the coil on the IPR valve. 65% duty cycle means that the coil is energized with 12V 65% of the time and de-energized 35% of the time. The on-off cycle happens very fast (haven't measured the frequency, but it's probably 10's of times per second) so what results is a fairly smooth effective signal. I can't say that 65% duty cycle equates to a fully closed IPR, but the amount of valve closure is proportional to the duty cycle signal (lower duty cycle = less valve closure and lower pressure, and higher duty cycle = more valve closure and higher pressure).So the duty cycle does not correlate to on/off time. It correlates to a magnetic force which is directly related to the position of the valve. At 65% duty cycle or more, the valve is in a location to pretty much block the drainage of oil.