Check/Adjust Ignition Setting, Idle Speed, CO-Content
*CO adjustment for the F-engine can be carried out in two ways:1. test diode 5280
2. CO-meter, Use connection 5151 and connect to outlet in front of catalytic convertor (F engine).
** Ignition setting cannot be adjusted, only checked.
(1) CO-ADJUSTMENT USING TEST DIODE 999 5280 (ONLY B 280 F)
Connect Test Diode 5280
Connect test diode green/white wire to test point at right wheel house (connector with green/white wire).
The test diode's red wire should be connected to battery's positive terminal (+).
Connect Test Instruments
- Tachometer
Warm Up Engine
Run engine at 25r/s (1,500 rpm)
NOTE: Run engine until radiator thermostat opens and then for a further 10 minutes.
Disconnect Crankcase Ventilator
Open the oil filler (1).
If the car is driven a lot in city traffic (starting, idling etc.), the oil in the engine can become slightly diluted by fuel. Crankcase emissions will then affect the CO adjustment.
Check Basic Adjustment Of Idling Speed
Ground the red-white wire in the diagnostic plug to close air control valve.
NOTE: Turn off air conditioning where applicable.
Idle speed should be: 11.7 r/s (700 rpm).
Adjust rpm with idle adjustment screw to 11.7 r/s (700rpm).
Disconnect ground from test point.
Engine speed should now rise to:
- 12.5 r/s (750 +/- 20 rpm)
Check/adjust Ignition Setting
Uneven idling can affect the ignition setting. The idling speed must not vary more than 0.8 r/s (50 rpm). Where fluctuations exceed this value, check that the air control valve hoses are not blocked or defective in any way.
Ignition setting should be as follows:
B 280 F 16° +/- 2°
Check Co-content
Test diode should blink if CO-content is correct.
If test diode remains on, the CO-content is too high
(rich air/fuel mixture).
If test diode remains off, the CO-content is too low
(too lean air/fuel mixture).
Adjusting Co-content
CO-content should be adjusted only after all possible faults have been checked/rectified.
Remove Seal
Turn off engine.
Drill two 2mm (0.8 in) holes in plug.
Withdraw plug with circlip pliers.
Start engine.
Adjusting Co-content
CO-screw should be turned until the test diode starts to flash.
Turning the adjustment screw:
- counter-clockwise reduces CO-content
- clockwise increases CO-content
Adjustment range for screw: 15 turns
Seal Adjustment Screw
The adjustment screw must always be fitted with a new sealing plug after CO-adjustment.
(2) Co-adjustment With Co-meter (B 280 F)
Connect Test Instruments
- Tachometer
- Monotester.
- CO-meter. Use connection 5151 and connect to outlet in front of catalytic converter double-sleeved exhaust pipe (F-engine).
In exhaust pipe having disconnected and plugged
Warm Up The Engine
Run the engine at 25 r/s (1,500 rpm).
NOTE: The engine should be warmed up until the radiator thermostat opens and for a further 10 minutes.
Disconnect Crankcase Ventilation
Open the oil filler (1)
If the car is driven a lot in city traffic (starting, idling etc.), the oil in the engine can become slightly diluted by fuel. Crankcase emissions will then affect the CO adjustment.
Check Basic Setting Of Idling Speed
Ground the red-white wire in air control valve diagnostic connector, to close valve.
NOTE: Turn off air conditioning if installed.
Adjust Idle Speed
Adjust engine speed with idle adjustment screw to 11.7 r/s (700 rpm).
Remove ground connection from diagnostic connector.
The engine speed should now increase to:
- 12.5 r/s (750 +/- 20 rpm).
Checking The Ignition Setting
Uneven idling can affect the ignition setting. The idling speed must not vary more than 0.8 r/s (50 rpm). Where fluctuations exceed this value, check that the air control valve hoses are not blocked or defective in any way.
Ignition setting should be:
- F-engine, 16° (+/- 2°) BTDC at idle.
Disconnect Lambda Sond (F-Engine)
CHECK CO-CONTENT
NOTE: CO-content should be checked/adjusted within 5 - 10 minutes of the radiator thermostat opening.
CO-content should be 0.2 - 1.0 %, F-engine .
Adjustment Of Co-content
CO-content should only be adjusted after all possible faults have been checked and rectified.
Remove Seal
Turn off engine.
Drill two 2 mm (0.08 in) holes in the plug.
Withdraw plug with circlip pliers.
Start engine.
Adjust Co-content
CO-content should be adjusted to 0.6% (B280 F)
Turning adjustment screw:
- counter-clockwise reduces CO-content
- clockwise increases CO-content
Adjustment range for screw: 15 turns.
Connect Lambda Sond (F-Engine).
Turn Off Engine
Disconnect test equipment. Install plug in exhaust pipe using sealant.
WARNING: THE EXHAUST PIPE AND CONNECTION 5151 ARE EXTREMELY HOT.
Seal Co-adjustment Screw
Use a new plug.
Tap plug into position.