Duty cycle greater than 100%

[ngaio75]

Hi,

Megatune is reporting duty cycle greater than 100%. I assume this is a config error - any clues on where to look. I'm running Megatune 2.25 p1 from 2008. I could try updating to the latest version but my Megasquirt has been very reliable and I'm a bit reluctant to update based on the if it ain't broke... principle.

Thanks
Mike

[DonTZ125]

Your controller is telling you it needs more fuel than the injectors can flow. The drivers are holding them open all the time (100% DC), and would like to hold them open longer, thanks.

Are you running alternating or simultaneous? Can you reduce the number of squirts? If you're running into a dead time / opening time issue with too many squirts, reducing the number of injections (by 2, for example) saves the time required to open the injectors those 2 instances.

Hope that made sense ...

[ngaio75]

Thanks for the reply. I'm running alternating with 2 squirts per cycle on a V6 so I'm at the minimum there.

I've improved the air intake (removed the AFM from the stock L-Jet system so I guess its not too surprising that the injectors are being maxed out (although it suggests very little headroom in the stock injectors with L-jet).

So if it works as you describe then the duty cycle reported by the controller is not a measured or actual value but rather a desired value which may or may not match actual. Interestingly I was achieving my desired AFR when duty cycle was above 110% so presumably going above 100% did make a difference.