Checking the idle speed and CO content (BMW 3 Series E30)

Connect the devices for measuring the number of revolutions and CO content in accordance with their operating instructions.

Warm up the engine to operating temperature. Oil temperature should be at least 60°C.

Check the ignition timing (see section "Checking and adjusting the ignition timing").

Check the tightness of the intake system. To do this, use a brush to wet all the joints of the intake device with gasoline. If you briefly increase the engine speed, air will be sucked in at the places of loose connections. Localize and eliminate leaks.

Warning: Do not inhale fuel vapors - poison! Do not allow gasoline to splash onto hot parts or the ignition system. Fire hazard!

Check the air filter element.

Turn off all electrical consumers.

Disconnect the crankcase ventilation hose from the cylinder head cover and route it so that only outside air can be sucked in.

Start the engine and let it idle.

Adjust the engine idle speed. For the specified value, see the table in the "Ignition System" section. If there are any deviations, adjust the idle speed with the adjusting screw at the throttle stop.

Check the CO content. For the specified value, see the table in the "Ignition system" section.

Remove the seal from the CO content adjustment screw "A".



If you don't have a special tool, pierce the plastic cap in the middle, screw in the appropriate screw or self-tapping screw and pull out screw "A" together with the seal.



Adjust the CO content with the adjusting screw "A" using a 3 mm Allen key, for example HAZET 4516.

Caution: When adjusting the CO content, do not press or lift the adjusting screw with a key. Do not apply gas when the key is installed (danger of bending).

After each attempt at adjustment, remove the key and briefly apply gas.

After adjustment, place a seal.

Turn off the measuring instruments.

Connect the engine crankcase ventilation hose.