The 3-wire narrow-band oxygen sensor is a replacement sensor for 1984-1987 BMW 325e, 1985-1986 BMW 535i, 635CSi, 1985 BMW 735i, 1986-1987 BMW 325es and 1988 BMW 325 in the upstream position. It signals whether the exhaust is running rich or lean so the engine computer can trim fuel delivery. A built-in heater brings the element to operating temperature quickly after a cold start.

Walker Products 350-33093 Oxygen Sensor Features:

• Fits 1984-1987 BMW 325e; 1985-1986 BMW 535i, 635CSi; 1985 BMW 735i; 1986-1987 BMW 325es; 1988 BMW 325
• Engine coverage includes 2.7L I6, 3.5L I6 applications
• 3-wire narrow-band oxygen sensor
• Built-in heater for fast warm-up
• M18x1.5 threaded mounting with a 22 mm hex, 500 mm (19.7 in.) overall length
• Male circle connector at the harness end
• Platinum electrode layer with a protective coating against combustion residue