Idle Speed/Throttle Actuator - Electronic: Service and Repair

REMOVING AND INSTALLING IDLE CONTROL VALVE





- Pull off plug (1).
- Disconnect retaining strap (2)
- Pull off idle control valve on hoses and remove.

Installation Note:





- Check code number (1).
- Check idle speed.

Note: Whether or not the idle control valve is running can be felt by taking hold of valve with a hand (cycled power supply).

Mechanical Test:





- The rotating piston (1) in the idle control valve must move when turning the idle control valve suddenly.

Electric Test:





- Measure resistance between terminals (1 and 3)
- Nominal value: approx. 40 ohms.
- Measure resistance between terminals (2 and 1) or (2 and 3).
- Nominal value: each approx 20 ohms

Dynamic Test:





- Remove idle control valve.
- Plug remains connected.
- Open rotating piston (1) completely or close.
- Turn on ignition.
- Rotating piston must take on a position of approx. 50 % the cross section opening and stay there.

Testing Procedures for Idle Speed Surging and Idle Speed of < or = 750 rpm, But Perfect (Checked) Idle Control Valve:





Requirements:
- Engine at operating temperature.
- No leak in intake system.
- Idle, speed CO level correct.
- All equipment (lights, air conditioner, etc.) switched off.
- BMW service test unit or digital tester connected
- There is no oil dilution,

- Oil dilution = gasoline in engine oil, possible in cold season of year and when car operated chiefly in stop-and-go traffic.





- Connect universal adapter between DME control unit and engine wire harness.
- Connect plug chambers (2/3/5) with each other (idle and full load contacts closed).
- Run engine at idle speed
- Proceed with troubleshooting, if idle speed is > or = 750rpm (fault is not within the idle regulation system).





- If the idle speed is < or = 750 rpm, the throttle valve basic setting must be changed.
- Loosen nut (1).
- Adjust connecting plate (2) with stop (3) (engine running) until the idle speed is 800 - 50 rpm.

Note: If the fault is not eliminated after adjusting the throttle valve, the throttle valve must be returned back to its original setting.

Cars with Active Carbon Filter Venting (US/J):
- There must not be vacuum in hose (4) at idle speed in spite of possible adjusted throttle valve - check.