Disobedient overrun fuel cut

[quattroant]

Hi all,

Having an issue with the fuel cut feature.

No matter if I set it at 8000cut/7900resume and 10kpa it will still pull all fuel on overrun showing me 18.91 afr all the way down to about 1500rpm until it puts fuel back?


Always done this with all previous fw and all versions of vt.
Any ideas why?

Partial cut settings...
Minpower learned is 0%
Maxpower learned is 100%

[GintsK]

Try to put there 0Kpa insteaad of 10.

Gints

[quattroant]

Tried 0kpa

No difference. You feel it cut and then ego is trying to put the fuel back and it judders as you slowdown in low rpm.

[GintsK]

Can you post the .vemslog file?

[Sprocket]

how well tuned is the very bottom line of your VE map?

[quattroant]

it's pretty close. not bang on but close enough I'd think it shouldn't cause a problem. it's very similar to the line above it which is fine if you free rev the engine, a little lean.

will post a file when I can work out how to do it again. Been a while

BTW i have ego on low ~800rpm to regulate lambda accurate around idle to try and get some decent emissions readings. That's why it starts messing with fuel while it's cutting but if i want to disable fuel cut it's not having it.

[GintsK]

It could be messed EGO correction under deccel. Bt for this purpose it is possible to switch EGOc off under deceleration loads.

[AVP]

question i have is why do you want to have fuel resume on overrun?

what is the point? When on overrun you want to have zero fuel there for economy. Are you experiencing any other issues and want to correct them with the overrun?