Engine Compression: 4-Cylinder
WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 1999 BMW Z3, 1999 BMW M3, 1999 BMW M Roadster, 1999 BMW M Coupe, and 1999 BMW 740iL. However, it is still accessible from the selected car via links, so may be relevant.
- Deactivate fuel injection system by removing Digital Motor Electronics (DME) master relay and fuel pump relay before performing compression test. See DME & FUEL PUMP RELAY LOCATION table. See Figure-Figure
. Ensure battery is fully charged.DME & FUEL PUMP RELAY LOCATION
Application Location 3-Series Z3 DME Relay Right Rear Corner Of Engine Compartment, Next To DME ECU Fuel Pump Relay Under Left Side Of Instrument Panel, Next To Kick Panel E36 DME & Fuel Pump Relays Left Rear Corner Of Engine Compartment, In Relay Box E46 DME Relay Left Rear Corner Of Engine Compartment, In Relay/ECU Box Fuel Pump Relay Behind Glove Box 5-Series & 7-Series DME Relay Right Rear Corner Of Engine Compartment, Next To DME ECU Fuel Pump Relay Right Side Of Trunk - Ensure engine coolant temperature does not exceed 95°F (35°C). Turn fasteners (2) on electric lead cover 90 degrees and remove electric lead cover. Disconnect spark plug connectors.
- Using 16-mm Socket (12-1-171) and Torque Limiter (12-1-172), remove spark plugs. Use Pressure Gauge (11-0-162), Test Adapter (11-0-166) and Tube Extension (11-0-167) to check compression pressure. See COMPRESSION SPECIFICATIONS table.COMPRESSION SPECIFICATIONS
Application Specification Compression Pressure Except M5 142-156 psi (10-11 kg/cm2 ) M5 170-199 psi (12-14 kg/cm2 )