Idle Speed/CO, Checking/Adjusting

Checking and Adjusting Idle Speed and CO%

CAUTION: It is important to follow work sequence when checking and adjusting idle speed and CO value

1. Check ignition timing; if necessary adjust
Idle stabilizer bypassed
Oxygen sensor connected

2. Check idle speed; if necessary adjust
Idle stabilizer bypassed
Oxygen sensor connected

3. Check CO value; if necessary adjust
Idle stabilizer connected
Disconnect oxygen sensor wiring connection with ignition OFF






Adjust CO value corresponding to local altitude. See shaded area of graph.
Reconnect oxygen sensor at electrical connection.

Preliminary conditions:

Engine oil temperature min. 6O°C (14O°F)
All electrical equipment must be turned OFF (radiator fan must not run)
Throttle valve switch must be ON at idle

CAUTION: Ignition must be switched OFF before connecting tester

Work sequence





- Connect tester V.A.G. 1367 as follows
A to alternator or terminal box
B to TDC sender

- Connect CO meter to receptacle in left exhaust pipe

Check ignition timing and adjust if necessary:





- Disconnect electrical plugs at idle stabilizer control unit (squeeze to release-arrows)
- Connect plugs together
- Start engine and check ignition timing and adjust if necessary
Spec = 5 ±1° ATDC
RPM below 1000

Check idle speed and adjust if necessary:

- Run engine at idle speed





- Check RPM after 2 minutes, if necessary adjust with screw (arrow)
- Stop engine

Check CO and adjust if necessary, idle stabilizer connected:





- With engine OFF disconnect electrical connection at oxygen sensor (arrow)
- Start engine and check CO value
Checking spec = 0.3 ±1.1%

Note: If CO value is above 1.1% pinch crankcase hose.
CO should drop below 1.1%

If YES, CO adjustment is not necessary (engine oil dilution-change engine oil)
If NO, adjust CO (continue with procedure)

- Stop engine

Adjust CO as follows:

- Remove intake air sensor 2





- Center-punch plug in CO adjusting hole
- Drill 2.5 mm (3/32 in) hole in center of plug 3.5 - 4.0 mm (9/64-5/32 in) deep

CAUTION: Clean up any metal shavings

- Screw in 3 mm (1/8 in) sheet metal screw
- Remove plug with screw, using pliers
- Reinstall intake air sensor 2
- Start engine (oxygen sensor disconnected)
- Adjust CO to 0.7 ±0.4%
- Stop engine
- Drive in new plug flush with intake air sensor
- Reconnect electrical connection of oxygen sensor

Note: With oxygen sensor and idle stabilizer connected
CO must be: 0.3 ±1.1%
Idle speed: 850 - 950 rpm