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Discussion Starter #1
Can anyone define IDC by crankshaft/camshaft positioning? i.e. is 100% duty cycle only in relation to the intake stroke, or does it include the exhaust stroke also?
 

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What car and engine? I don't believe it ever goes to 100% duty cycle. The duty cycle decision gets inputs, I believe, from the HEP signal (RPM), MAP, TPS and O2 sensor.
 

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Discussion Starter #3
General question-no Mopar cars involved. Just would like to know what my scanner is telling me. If car is at 100% duty cycle, does it spray thru just the intake, or during both strokes?
 

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100% duty cycle means that the injector is spraying continuously, it never shuts off, even for an instant. I can't imagine that that should happen for longer than a fraction of an instant. It would flood the engine.
 

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Discussion Starter #5
Be thankful you guys have Mopars- probably better fuel mgmt. On some Gov't Motors cars, opening up the intake and exhaust will lead to 100% duty cycle 'cause they're fuel mgmt. is already on the hairy edge.
 

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Time on/( time on+ time off) * 100
Its a simple time count that doesent take any revulotions into countat all.
lets say that you run at 2000 rpm´s and have a duty cycle of 50% and then
yourun the engine at 4000 rpm´s with the same amount air passing at each revolution you will
end up at 100%, so the faster you spin the bigger injector will needed.
In the 2 mopars ive tried e-85 in ive seen that for a unmodified engine there was enough capacity to
tolerate the 30% increase in fuel flow...didnt even lit the lamp.
 

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Discussion Starter #7
Apparently duty cycle is a percentage of 1 complete power cycle (2 crank rotations). I know what my cam duration is and I don't want to create a CIS system. Matching injectors and fuel pump to get duty cycle I can live with.
 

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Yeah, duty-cycle is the on-time (spray) compared to the off-time of the injector. Some scan tools measure the injector on-time in milliseconds (ms). General on-time at idle is 2-3 ms and as the rpm or load goes up, the injector on-time increases also.
Domestic Chryslers use the speed/density EFI type system.

http://www.carcraft.com/techarticles/electronic_fuel_injection/

http://en.wikipedia.org/wiki/Fuel_injection
 
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