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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.
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).
 

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You changed your fuel pump. But have you verified your pressure? What about the uptake in the tank. Screens clogged? Line cracked sucking air?
 

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Discussion Starter #23
Does the auto enginuity do the power balance test? Havn't had a chance to test the injectors yet. Turned stupid cold with snow from 70 degree weather. Welcome to Kansas.. Need to check the fuel pressure too. No one reants those things at least not for a diesel anyway.
 

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Does the auto enginuity do the power balance test? Havn't had a chance to test the injectors yet. Turned stupid cold with snow from 70 degree weather. Welcome to Kansas.. Need to check the fuel pressure too. No one reants those things at least not for a diesel anyway.
It will do CCT and PERDELS.
 

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CCT is a cylinder contribution test. PERDEL is percent deceleration from each cylinder. Both need to be done when the engine is at operating temperature. Both are variants of a power balance test.


Sent from AutoGuide.com Free App
 

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Discussion Starter #27
I will have to look for those tests. I will do that in the next day or two an report back what I find. Truck runs fine but dam that knock just isn't right.
 

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Unplug injectors one at a time and see if the knock goes away.
Or use AE to do it
 
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