Checklist Engine Overrun Setup

This guide shows the recommend method to configure the Engine Overrun system. Clicking each item (M1 Tune v1.5 only) will select the item and allow you to enter the required information. Once an item has been selected the help, for that item, can be displayed by hitting the F1 key.

For this system to function Engine Overrun Mode must be Enabled.

Engine Overrun will activate when certain conditions are met. After a transition phase with progressive ignition retard fuel will be cut. When exiting engine overrun fuel injection will be resumed with the assistance of ignition advance.

Engine Overrun State reports the current state of the system. A description of each state follows.

Disabled

No control is exercised.

The system will transition to Retard Ignition if the following conditions are met for Engine Overrun Delay seconds:

• Engine Speed is greater than Engine Overrun Engine Speed Threshold + Engine Overrun Engine Speed Hysteresis.
• Vehicle Speed is greater than Engine Overrun Vehicle Speed Threshold + Engine Overrun Vehicle Speed Hysteresis.
• Throttle Position is less than Idle Activate Throttle Pedal Threshold.
• No gear shift is processed (Gear Shift State is Idle or Rearm).

Retard Ignition

Ignition timing is progressively retarded at Engine Overrun Ignition Timing Retard Rate.

• If Engine Overrun Ignition Timing Target is reached the system transitions to Enabled.
• If Engine Speed falls below Engine Overrun Engine Speed Threshold the system transitions to Advance Ignition.
• If Throttle Pedal rises above Idle Activate Throttle Pedal Threshold + Idle Activate Throttle Pedal Hysteresis the system transitions to Advance Ignition.
• If a gear shift is processed (Gear Shift State assumes another value than Idle or Rearm) the system transitions to Disabled.

Enabled

Fuel injection is disabled.

• If Engine Speed falls below Engine Overrun Engine Speed Threshold the system transitions to Advance Ignition.
• If Throttle Pedal rises above Idle Activate Throttle Pedal Threshold + Idle Activate Throttle Pedal Hysteresis the system transitions to Advance Ignition.
• If a gear shift is processed (Gear Shift State assumes another value than Idle or Rearm) the system transitions to Disabled.

Advance Ignition

Ignition timing is progressively advanced at Engine Overrun Ignition Timing Advance Rate.

The system transitions to Disabled when ignition timing returns to normal or if a gear shift is processed.