Mechanical Inspection: Compression
Warm engine to normal operating temperature before checking compression. Ensure battery is fully charged. Remove ignition coils and spark plugs. On all vehicles except GX470, see IGNITION SYSTEM in REMOVAL & INSTALLATION - EXCEPT GX470 article. On GX470, see IGNITION SYSTEM in REMOVAL & INSTALLATION - GX470. Check engine mechanical condition with a compression gauge, vacuum gauge, or engine analyzer with throttle fully open. See engine analyzer manual for specific instructions. See COMPRESSION SPECIFICATIONS table. Install and tighten spark plugs to 13 ft. lbs. (18 N.m).
COMPRESSION SPECIFICATIONS
| Application | Specification | |
|---|---|---|
| Normal Compression Pressure | ||
| ES300 & RX300 | 218 psi (15.3 kg/cm2 ) | |
| GS300, IS300 & LX470 | 192 psi (13.5 kg/cm2 ) | |
| GS430, GX470, LS430 & SC430 | 178 psi (12.5 kg/cm2 ) | |
| Minimum Compression Pressure | ||
| ES300 & RX300 | 145 psi (10.2 kg/cm2 ) | |
| GS300 & IS300 | 156 psi (11.0 kg/cm2 ) | |
| GS430, GX470, LS430, LX470 & SC430 | 142 psi (10.0 kg/cm2 ) | |
| Maximum Variation Between Cylinders | ||
| Except ES300 & RX300 | 14 psi (1.0 kg/cm2 ) | |
| ES300 & RX300 | 15 psi (1.1 kg/cm2 ) | |