Note: The adjustment described below is for a 112 hp engine. (dZ designation). The differences in adjustment of other engines are given at the end of the chapter.
Warm up the engine, oil temperature +80°C.
Turn off all electrical consumers, including the air conditioner.
If the injection pipes have been loosened or replaced, before checking, rev the engine up to 3000 rpm several times and let it idle for at least 2 minutes.
Check the ignition timing.
Clamp the hose from the dual-line valves with clamp "1" to increase the idle speed.
Disconnect the hose "2" of the crankcase ventilation on the cylinder head and position it so that fresh air can be sucked in. If the hose is secured with a wire clip, use the special pliers HAZET 798-4.
Attention: Connect measuring instruments only when the ignition is off.
Connect the tachometer and CO measuring device according to the instructions.
Caution: The fan controller must not be operated during testing and adjustment.
Check the idle speed, it should be: 900±100 rpm.
Check the CO content, it should be: 1.0±0.5%.
If necessary, achieve the required values with the idle speed adjustment screws "A" and CO content "B".
Remove the CO adjustment screw plug. To do this, drill it with a 2.5 mm drill, screw in a 3 mm screw and remove it together with the plug with pliers.
Set the CO content with a 3 mm Allen key -arrow-, for example HAZET4516.
Caution: When adjusting the CO, do not press the adjusting screw up or down with the key. Do not apply gas when the key is in place.
After each adjustment, immediately remove the key and press the gas.
After adjustment, press in the new plug using a suitable rod.
Put on the crankcase ventilation hose and secure it with a clamp.
Note: If the CO content now increases, the reason is not incorrect adjustment, but rather enrichment of the mixture from the crankcase due to dilution of the oil by gasoline during short trips in cold weather.
With a longer trip, the proportion of fuel in the oil decreases and the CO content normalizes. This can be achieved with a 30-minute trip or a scheduled oil change.
Turn off the measuring instruments when the ignition is off.
Remove the hose clamp.
5-cylinder engine
Connect the ammeter with the VAG 1315A/2 connecting wire to the idle speed stabilization control valve. If there is no connecting wire, connect the ammeter in series between the removed plug and the control valve.
Caution: Connect the measuring device only when the ignition is off.
115 hp engine: Clamp the crankcase ventilation hose "1" with a suitable screw clamp. Remove the oil level indicator. To avoid splashing, place a rag under the guide of the indicator.
136hp Engine: Disconnect the crankcase ventilation hose and plug with a suitable plug.
Start the engine and let it idle.
Check the control current; it should be within 430±10 mA and fluctuate slightly.
Check CO content; should be: 1.0±0.2%.
If necessary, achieve the required values by turning the adjusting screws "A" for idle speed, "B" for CO content.
Check the idle speed. It should be: 750-850 rpm.
If the parameters are outside the permissible limits, check the idle speed stabilization. This should also be done if the measured control current (470 mA) does not change when turning the adjusting screw "A".
This article was copied from an online resource AUDImanual