Idle speed adaptive correction

F4R

I - ADAPTIVE IDLE SPEED CORRECTION

Principle

Under normal operating conditions when hot, the idle opening duty cycle PR091 varies between a high value and a low value in order to achieve the nominal idle speed.

After operating variation (running-in, engine fouling...), the idle opening duty cycle value may be close to the high or low values.

The adaptive correction PR090 on the idle opening duty cycle compensates for slow variations in the engine's air requirement, so as to re-center the idle opening duty cycle on an average nominal value.

This correction is only active if the coolant temperature is above 75 °C, 1 minute after engine start, and when in idle control phase.

II - IDLE OPENING DUTY CYCLE VALUE AND ITS ADAPTIVE CORRECTION

• PR055: "engine speed"

• 750 rpm

• PR032: "intake pressure"

• 300 mbar < or = X < or = 400 mbar

• PR091: "theoretical idle control opening duty cycle"

• 5% < or = X < or = 35%

• PR090: "idle control learning value"

• minimum limit: -11.75%
• maximum limit: +11.75%

Note: The parameter names shown in the CLIP tool have changed.

From now on:

• the "theoretical idle control opening duty cycle" is now called "theoretical idle control duty cycle",
• the "adaptive" idle control opening duty cycle parameter is now called "idle control learning value".

III - INTERPRETATION OF THESE PARAMETERS

"In case of excess air" (air leak, misadjusted throttle stop...), engine speed increases at idle.

The idle opening duty cycle value decreases to return to the nominal idle speed; the adaptive idle opening duty cycle correction value decreases to re-center the idle opening duty cycle.

"In case of an air shortage" (fouling...), the logic is reversed: the idle control duty cycle increases and the adaptive correction increases likewise, to re-centre the idle speed control operation.

WARNING

After erasing the ECU memory, it is imperative to start the engine, stop it, then let it run at idle so that the adaptive correction can re-adjust correctly.

K4J or K4M

I - ADAPTIVE IDLE SPEED CORRECTION

Principle

Under normal operating conditions when hot, the idle opening duty cycle PR091 varies between a high value and a low value in order to achieve the nominal idle speed.

After a production scatter (running-in, engine mounting...), the idle opening duty cycle value may be close to the high or low values.

The adaptive correction PR090 on the idle opening duty cycle compensates for slow variations in the engine's air requirement, so as to re-center the idle opening duty cycle on an average nominal value.

This correction is only active if the coolant temperature is above 75 °C, 1 minute after engine start, and when in idle control phase.

II - IDLE OPENING DUTY CYCLE VALUE AND ITS ADAPTIVE CORRECTION

• PR055: "engine speed"

• 750 rpm

• PR032: "intake pressure"

• 300 mbar < or = X < or = 400 mbar

• PR091: "theoretical idle control opening duty cycle"

• 6% < or = X < or = 22%

• PR090: "idle control learning value"

• lower limit: - 6.25%
• upper limit: + 6.25%

III - INTERPRETATION OF THESE PARAMETERS

"In case of excess air" (air leak, misadjusted throttle stop...), engine speed increases at idle.

The idle opening duty cycle value decreases to return to the nominal idle speed; the adaptive idle opening duty cycle correction value decreases to re-center the idle opening duty cycle.

"In case of an air shortage" (fouling...), the logic is reversed: the idle control duty cycle increases and the adaptive correction increases likewise, to re-centre the idle speed control operation.

WARNING

After erasing the ECU memory, it is imperative to start the engine, stop it, then let it run at idle so that the adaptive correction can re-adjust correctly.