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2.2L Turbo Engine

  1. Ensure engine is at normal operating temperature. Ensure all electrical accessories and cooling fan are off. Throttle valve must be in idle position, and coolant switches must not be defective. TDC sensor must be fully seated in transaxle.
  2. Disconnect wire from terminal No. 1 of ignition coil. Terminal identifications are located on coil. Remove crankcase breather hose and plug cylinder head openings. Crankcase vapors must vent to atmosphere. Remove cap from charcoal canister "T" fitting and vent to atmosphere. See Fig 1 .
  3. Remove cap from exhaust probe receptacle and connect CO meter. Ensure fit is snug to prevent exhaust leaks. Connect Engine Analyzer (VW 1367)and start engine. Check idle speed and adjust to specification if necessary. Refer to the 5-CYLINDER IDLE SPEED & CO LEVEL SPECIFICATIONS  table.
    NOTE: If injection lines were disconnected or replaced, increase engine speed to 3000 RPM several times, and then allow engine to idle for at least 2 minutes to bleed injectors and lines.
    Fig 1: Breather Hose & "T" Fitting Locations
    G93049Courtesy of AUDI OF AMERICA, INC.
  4. Using Cable Adapter (US 1112), connect test lead to Blue/Black oxygen sensor test connector. Depress "%" (dwell angle) button on engine analyzer. Disregard RPM reading. With oxygen sensor connected, check CO level. Refer to the 5-CYLINDER IDLE SPEED & CO LEVEL SPECIFICATIONS  table. Oxygen sensor duty cycle must fluctuate between 25-65 percent.
  5. If CO reading is more than 1.2 percent with oxygen sensor duty cycle reading between 25-65 percent, check ignition system, exhaust system and fuel distributor. If oxygen sensor duty cycle is NOT between 25-65 percent, then CO level needs adjustment, or fuel system, ignition system or emission system needs repairing.
  6. Stop engine and remove air intake duct from airflow meter. Punch hole in center of CO adjusting screw plug and drill a 3/32" hole to a depth of 5/32". DO NOT  drill completely through as adjustment screw will be damaged.
  7. Install a 1/8" sheet metal screw and remove plug using pliers. Install air intake duct on airflow meter. Start and briefly increase engine speed to 2000 RPM, then allow it to return to idle.
    NOTE: DO NOT  push down on adjustment screw and DO NOT  accelerate engine with adjusting wrench in place. Remove wrench after each adjustment and accelerate engine briefly before measuring CO level.
  8. Using Adjustment Wrench (P 377), adjust oxygen sensor duty cycle until it fluctuates between 42-58 percent. Check idle speed and adjust if necessary. Turn engine off. Install new plug in mixture control unit. Remove all test equipment and connect all hoses and wiring.
NOTE: Idle speed on vehicles with 2.3L engine is electronically controlled and CANNOT be adjusted.
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