MSefi.com read only forum (Jan.15,2018)

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

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 ...

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.