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Home >> Mercedes Benz >> 1985 >> 380SL >> Repair and Diagnosis >> Engine Performance >> System >> Fuel Injection System - BOSCH Cis >> Lambda Control System Checks >> Operation Check & Adjustment
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Operation Check & Adjustment

  1. After preparations are complete and engine is at operating temperature, disconnect wiring plug to O2 sensor. Voltmeter reading should be steady and not fluctuate. Steady reading indicates on/off cycle of 50/50. Mark reading on dial of voltmeter with felt tip or adhesive tape as a reference point.
  2. Reconnect O2 sensor plug. Check voltmeter reading. If reading is fluctuating around marking on dial, operation is correct. If not, turn mixture adjusting screw until reading is fluctuating around marking on dial. Accelerate briefly and recheck ratio and idle speed. Adjust if necessary.
Fig 1: Bosch CIS Lambda ECU Wiring Diagram
G74092