Engine Compression
To check engine compression, bring engine to normal operating temperature. On LS400 models, disconnect cold start injector. On all models, disconnect distributor electrical connector(s). Remove all spark plugs. Remove air intake hose from throttle body and fully open throttle. Measurement should be done at 250 RPM in as short a time as possible.
COMPRESSION SPECIFICATIONS
| Application | Specification | |
|---|---|---|
| Compression Ratio | ||
| ES250 | 9.0:1 | |
| LS400 | 10.0:1 | |
| Compression Pressure | 178 psi (12.5 kg/cm2 ) | |
| Minimum Compression Pressure | 142 psi (10 kg/cm2 ) | |
| Maximum Variation Between Cylinders | 14 psi (1.0 kg/cm2 ) | |