This feature will cut fuel to the engine under low load conditions. This will save fuel in town and downhill driving. The engine will run against compression as you are decelerating. It will also prevent flaming in the exhaust during accelerator blip.

The injectors will be cut when the MAP sensor value is below the Vacuum fuel cut off setting and the engine RPM is above the RPM fuel cut off setting.

The Vacuum fuel cut off setting is chosen as a value lower than idle vacuum. A good value is usually 0.08 bar for a standard street car. The RPM fuel cut off setting is about 500 RPM higher than idle RPM. Rotary and racing engines may need some extra RPM’s.

There is a dead band feature built into these settings to prevent jerking when you are cruising close to the settings. When tuning these parameters use third gear at around 2000 rpm and release the throttle. Look at the real-time injection bar and you will see that it goes to zero value which means the injectors are switched off.

You will also notice in information code at the right-hand bottom of the screen indication that this feature is activated.

Now, let the car reduce speed by itself till injection is restored and the engine is running by itself again. This change over point must occur when the engine reaches idle RPM’s. If it jerks in the car, reduce or increase one of the settings till it comes-in unnoticed.