Digifant injection system, engines with designations ABF, PF, PB, PG, 2E
Caution: Idle speed, CO content and ignition timing must be checked and adjusted together. In engines with a regulated catalytic converter, the oxygen sensor remains connected during testing.
Prerequisite for checking: the exhaust system must be tight.
Warm up the engine until the engine oil temperature is not lower than +80°C.
Turn off all electrical consumers, as well as the air conditioning system.
If the fuel lines have been disconnected or replaced, before checking the engine shaft must be brought to a speed of 3000 1/min several times, and then the engine must be left to idle for at least two minutes.
Attention: Connect the devices only when the ignition is off.
Check the ignition timing, see chapter "Ignition system".
Make sure that the crankshaft speed stabilization system valve works when the engine is idling. To do this, turn on the ignition and place your hand on the valve. The valve should vibrate and buzz audibly. The valve is located above the cylinder head, next to the throttle valve pipe, see above.
Connect the crankshaft speed meter according to the service manual.
Engine with adjustable catalytic converter (designations ABF, PF, PB, PG, 2E): connect the CO measuring device to the CO sampling pipe in the engine compartment. The sampling pipe is welded to the front exhaust pipe and is usually closed with a light blue cap.
Attention: Securely attach the measuring instrument hose to the sampling tube and ensure that the connection is tight.
112 hp engine. (rV designation): connect the CO measuring device to the final outlet pipe.
Disconnect the crankcase ventilation hose at the pressure regulating valve -arrow 1-. Close the hose, for example, with a plug, a screwdriver handle or by pinching. Engine with the designation ABF, 2E: disconnect the double hose at the pressure regulating valve and close only the opening of the hose leading to the intake air hose. If there are two separate crankcase ventilation hoses, disconnect the ventilation hose from the intake air hose and seal the opening in the intake air hose with a plug. For this purpose, you can use the inspection hole cap for setting the TDC position, see Chapter "Ignition system".
Start the engine and let it idle.
After 1 minute, disconnect the temperature sensor plug (blue) (arrow 2). Engine 2E up to 7/92: After the cooling system fan has already been switched on once, disconnect the coolant temperature sensor plug with the throttle valve closed.
Give the gas three times, increasing the crankshaft speed to a value greater than approximately 3000 1/min. Then let the engine idle.
Attention: During testing and adjustment work, the cooling system fan must not rotate.
Check the crankshaft speed and CO content when idling. If necessary, adjust the above parameters to the specified values by alternately turning the speed adjusting screw "1" and the CO content adjusting screw "2".
1) The specified CO content value is valid up to an altitude of 300 m above sea level. If the adjustment location is above 300 m, then for every subsequent 100 m of altitude it is necessary to add 0.2% by volume. Example: at an altitude of 700 m above sea level, the RV engine should have a CO content of 1.8 ±0.5% by volume.
2) The temperature sensor plug (blue) is disconnected.
Reconnect the blue plug of the temperature sensor and secure it.
Give it gas three times, then let the engine idle.
Check the crankshaft speed and CO content again when idling. The crankshaft speed should now decrease to 800 ±50 1/min.
Note: For engines with a regulated catalytic converter, the CO content after connecting the temperature sensor plug is regulated regardless of the altitude to a value of 0.7 ±0.4% by volume.
Engines with catalytic converter (designation PF, PG and 2E up to 7/92)
Checking the oxygen sensor adjustment. To do this, disconnect the hose from the pressure regulator at the throttle valve pipe and close the connecting element. The CO content should increase briefly and then decrease again. This indicates that the oxygen sensor adjustment is in good order. Otherwise, check the oxygen sensor adjustment. Put the hose back on.
Connect the crankcase ventilation hose to the pressure control valve or, respectively, to the intake air hose and secure with a clamp.
Note: If the CO content has now increased, the reason is not incorrect adjustment, but rather the enrichment of the combustible mixture due to the influx of gasoline vapors from the crankcase, where gasoline gets mainly during short-distance trips.
During long, continuous trips, the proportion of gasoline in the engine oil decreases, and the CO content in the exhaust gases returns to normal. This can also happen quickly after about a 30-minute trip or another oil change.
Measuring instruments must be switched off when the ignition is off.
Reconnect all disconnected hoses and wires.
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