Engine Compression
- Ensure battery is fully charged and engine is at normal operating temperature. Allow engine to cool for 10 minutes. Remove spark plugs and disconnect ignition coil primary connector.
- Hold throttle valve fully open during test. Attach compression gauge and crank engine until maximum pressure is reached at each cylinder. See COMPRESSION SPECIFICATIONS
table. Lowest cylinder pressure should be at least 75 percent of highest cylinder pressure.
COMPRESSION PRESSURE SPECIFICATIONS
| Application |
Minimum psi (kg/cm2
) @ RPM |
Standard psi (kg/cm2
) @ RPM |
| Miata (1.6L) |
135 (9.5) @ 300 |
192 (13.5) @ 300 |
| Protege (1.8L) |
| SOHC |
121 (8.5) @ 300 |
173 (12.2) @ 300 |
| DOHC |
128 (9.0) @ 300 |
182 (12.8) @ 300 |
| 323 (1.6L) |
135 (9.5) @ 300 |
192 (13.5) @ 300 |