Idle Speed: Adjustments

Fig. 81 BMW Special Tools For Idle Control System:

Fig. 82 Special Tool Connection Diagram:

***UPDATED BY TSB# 130388 (1589), FEB 88

Special Equipment Required, Fig. 81:
BMW idle control valve current probe,
Digital multimeter (Fluke 8021B, or equivalent)
Exhaust gas analyzer

1. Connect the idle control valve (ICV) current probe in series with the idle control valve and the harness plug, Fig. 82.
2. Set the multimeter to the 2000 mA range.
3. Connect the multimeter to the ICV current probe.
4. Start the engine (oil temperature should be at least 60°C/140°F)
5. Switch OFF all electrical consumers such as A/C, stereo, rear window defroster, etc.
6. Check the current reading of the ICV with engine at idle. Values should be:
Manual Trans: 460 +/- 5 mA 800 - 900 rpm
Automatic Trans: 460 +/- 5 mA 700 - 800 rpm
7. If the current readings are not within specification, adjust the idle control valve.
a. Turn the adjustment screw on the side of the control valve clockwise (completely closed).
b. Slowly open the adjustment screw until 460 mA and the proper rpm is reached.
Note. Do not turn the adjustment screw too fast as you can easily overshoot the proper adjustment point.
8. Connect an exhaust gas analyzer to make sure the fuel mixture is within specification (0.2 - 1.2%). Adjust mixture as necessary, then readjust the idle control valve.
9. Disconnect all test equipment.