CO-Adjustment

Fig. 250 AIR-FUEL CONTROL UNIT:

CO content should be checked at test plug upstream of catalytic converter. Initial CO-adjustment is made at the factory and should not need to be changed. The access hole to the CO-screw is sealed with a steel ball. Fig. 250 If CO is not within specifications (see emission sticker or "SPECIFICATIONS"), and all other causes for incorrect CO readings have been checked, follow the adjustment procedure as described below.

Fig. 269 REMOVE AIR-FUEL CONTROL UNIT:

1. Open fuel cap to release tank pressure. Close fuel cap.
2. Disconnect battery ground cable.
3. Disconnect all fuel lines at air-fuel control unit. Be careful not to allow dirt to enter air-fuel control unit.
4. Remove air-fuel control unit.
5. Separate upper body from lower body by removing retaining screws. Fig. 269

Fig. 270 REMOVE STEEL BALL:

6. Turn air-fuel control unit upside down and punch out steel ball with a 3 mm slightly bent punch. Fig. 270.

Fig. 258 DISCONNECT LAMBDA SOND (OXYGEN SENSOR):

7. Reassemble and install air-fuel control unit.
8. Reconnect all fuel lines using new copper washers.
NOTE:
The fuel distributor fitted to turbo engines is the same as used on six cylinder engines. Except, there are two fuel outlet ports plugged. Do not connect the fuel lines to these ports.
9. Reconnect battery ground cable.
10. Disconnect Lambda sond (oxygen sensor) at wire connector. Fig. 299.

Fig. 259 REMOVE TEST PLUG:

11. Remove test plug upstream of catalytic converter. Fig. 259.
12. Connect CO-meter and tachometer.
13. Run engine to operating temperature and five minutes beyond.
14. Check idle speed (900 ± 20 RPM). Idle speed is controlled by an electronic control unit (ECU). Adjust idle speed only if it is out of specified tolerances, see "IDLE SPEED".

Fig. 300 CO ADJUSTMENT:

15. Check and adjust CO content. CO content can be 0.7 - 1.3 %, set CO to 1.0 % if adjustment is necessary. Fig. 300. Use VOLVO tool #5015 or equivalent. Cover the adjusting hole between adjustments when taking CO readings.
16. Reconnect Lambda sond (oxygen sensor). CO should drop below 1.0 %.
17. Recheck idle speed (900 ± 20 RPM).

Fig. 302 REINSERT STEEL BALL:

18. Reinstall the steel ball into air-fuel control unit using VOLVO tool #5232 or equivalent. Use a light hammer to tap ball into position. Fig. 302.
19. Remove all test equipment and reinstall the exhaust pipe plug.