Check Idle, Emission Level/Lambda Control (HFM)

Check Idle, Emission Level/Lambda Control And Readjust (HFM Sequential Multiport Fuel Injection/Ignition System)



















Testing

Danger:
- Risk of accident. Accidents may result if the vehicle starts off unintentionally with the engine running. Risk of injury's working around the engine during start-up or while running may result in contusions and burns
- Secure vehicle to prevent it from moving.
- Wear closed and snug-fitting work clothes.
- Do not grasp hot or rotating parts.
- Hazard from touching parts which conduct high voltages
- Do not touch parts carrying high voltages.
- Persons who wear electronic implants (e.g. heart pacemakers) must not carry out work on the ignition system.

1 Connect tester

CAUTION: Ignition: OFF

2 Check adjusting linkage
- If the throttle lever sits close to the closed throttle stop
3 Check adjustment of slotted lever
- The roller (32/8) must sit close to the closed throttle stop free of tension in the slotted lever (32/6).
- On complaint (against separate order)
- Adjust adjusting linkage

NOTE:
- On vehicles with ASR (CODE 471)
- If ignition is switched on do not operate adjusting linkage in engine compartment, otherwise faults are recognized as implausible and are stored in the control module of the electronic accelerator.

4 Test idle speed
Idling speed - Selector lever position "P"/"N", engine oil temperature approx. 80 degrees C = 700 + 100/ -50 rpm

Engine: Idle
Selector lever position: P
AC compressor: OFF
Engine oil temperature: approx. 80 degrees C

- On complaint (against separate order) [down arrow]
- Check electronic accelerator/cruise control/idle speed control
- Check cruise control/idle speed control
- Check idle speed control

5.1 Check idle speed exhaust value
Idle emission value = 1.5 ± 0.5 %CO

Without TWC
Engine: Idle
Selector lever position: P
AC compressor: OFF
Engine oil temperature: approx. 80 degrees C

- Measure idle speed exhaust value at exhaust end pipe.

5.2 Adjust idle speed exhaust value

Vehicles with potentiometer
- See Special Tools below, pull out locking plug with the extractor from the CO potentiometer (R33).
- Adjust idle speed exhaust value with adjusting screw at CO potentiometer (R33).
- Rotate toward left = leaner
- Rotate toward right = richer
- After each adjustment, accelerate and check once again.
- After the adjustment a blue locking plug, part no. 002 997 16 86, has to be installed.

Vehicles without potentiometer
- Call up in the HHT Menu HFM sequential multiport fuel injection/ignition system functions No. 7 correction programming.

6 Check engine running
Parking brake: Operate
Engine: Idle
Selector lever position: D
all consumers: ON
Engine must run properly

Special Tools:

Commercially Available Tools: