- 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. Ensure battery is fully charged.
- Ensure engine coolant temperature does not exceed 86°F (30°C). Remove oil filler cap. Remove 2 nut covers and nuts securing cylinder head cover(s). Remove cylinder head cover(s). Disconnect ignition coil connectors.
- Remove ignition coils. 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»(ref-10047-S03875525742000110700000) table.
| Application | Location |
|---|
| Z3 |
| DME Relay | Under Left Side Of Instrument Panel, Next To Kick Panel |
| Fuel Pump Relay | Right Rear Corner Of Engine Compartment, Next To DME ECU |
| 3-Series (1) |
| DME & Fuel Pump Relays | Left Rear Corner Of Engine Compartment, In Relay Box |
| 5-Series & 7-Series |
| DME Relay | Right Rear Corner Of Engine Compartment, Next To DME ECU |
| Fuel Pump Relay | Right Side Of Trunk |
| 8-Series |
| DME & Fuel Pump Relays | Right Rear Corner Of Engine Compartment, Next To DME ECU |
| (1) (Scheme 1)and (Scheme 2). |
DME & FUEL PUMP RELAY LOCATION
Scheme 1
Scheme 2
| Application | Specification |
|---|
| Compression Ratio |
| 4-Cylinder | 10.0:1 |
| 6-Cylinder |
| M3, Z3 & 328 Series | 10.2:1 |
| 323 Series | 10.5:1 |
| V8 | 10.0:1 |
| Compression Pressure |
| All Models | 142-156 psi (10-11 kg/cm 2 ) |
COMPRESSION SPECIFICATIONS
