Emissions - CO Measurement Directions

GROUP 13
Fuel Supply & Adjustments

Bulletin Number
13 01 82

Montvale, NJ
February 1982
Technical Dept.

SUBJECT:
IDLE CO ADJUSTMENT/CHECK

MODELS:
1982 528e, 633CSi, 733i

To obtain an accurate idle CO measurement, use the following procedure:

1. Remove idle test plugs in exhaust manifolds and connect CO-meter probes.

2. Start Engine and read idle CO content at normal operating temperature (range specification 0.2 - 1.2% vol.).

3. Disconnect oxygen sensor lead.

4. Disconnect purge line at the carbon cannister and leave purge line open to atmosphere. DO NOT DISCONNECT PURGE LINE AT THE INTAKE MANIFOLD as would will create a severe vacuum leak and produce incorrect idle CO readings. By disconnecting the purge line at the carbon filter, the purge valve acts as a restrictor which will reduce outside air intake.

5. Disconnect the wiring plug from the purge valve. This will keep the valve in the open position and prevent the valve from cycling.

6. Compare CO content values.

7. When procedure has been completed, reconnect wiring plug, purge line, and idle test plugs.