Compression Check: Testing and Inspection
(1) Prior to inspection, check to ensure that the engine oil, starter motor and battery are in proper condition. Place the vehicle in the following conditions.- Engine coolant temperature: 80 - 95° C (176 - 203° F)
- Lights, electric cooling fan and accessories: OFF
- Transaxle: Neutral (P for A/T)
(2) Remove the spark plug cables.
(3) Remove all of the spark plugs.
(4) Disconnect the crankshaft position sensor connector.
NOTE: By so doing the engine control module stops performing ignition and fuel injection.
(5) Cover the spark plug mounting holes with a shop towel, crank the engine, and then check for foreign substances deposited on the shop towel.
CAUTION:
1. When you crank the engine, keep away from the spark plug mounting holes.
2. If a compression measurement is performed with water, oil, fuel, etc. in the cylinder due to the cracks in the cylinders, these substances heated to a very high temperature will blow off the spark plug mounting holes and could be dangerous.
(6) Install a compression gauge in a spark plug mounting hole.
(7) Set the throttle valve in a fully opened position, and crank the engine to measure the compression pressure.
Standard value:
[SOHC]:
1,180 kPa (171 psi) [250 - 400 r/min]
1,270 kPa (185 psi) [250 - 400 r/min]
1,080 kPa (156 psi) [250 - 400 r/min]
Limit:
[SOHC]:
Minimum 875 kPa (127 psi) [250 - 400 r/min]
minimum 959 kPa (139 psi) [250 - 400 r/min]
DOHC - Turbo>:
minimum 792 kPa (115 psi) [250 - 400 r/min]
(8) Measure the compression pressure in each of the cylinders and check that the difference in compression pressure between the individual cylinders is less than the limit value.
Limit: maximum 98 kPa (14 psi)
(9) If there is a cylinder in which the compression pressure or pressure difference is beyond the limit value, pour in a small amount of engine oil through the spark plug mounting hole, and repeat Steps (7) through (8).
1) If the small amount of oil poured in causes the compression pressure to rise, then it is likely that either the piston ring, cylinder wall surface or both are worn or damaged.
2) If the small amount of oil poured in does not cause the compression pressure to rise, then valve seizure, poor valve contact, or leakage from the gasket is suspected.
(10) Re-connect the crankshaft position sensor connector.
(11) Re-mount the spark plugs and spark plug cables.
(12) Erase the diagnostic trouble code using the scan tool or disconnect the negative (-) terminal of the battery, leave it disconnected for more than 10 seconds, and then re-connect it.
NOTE: This erases the trouble code due to the disconnection of the crankshaft position sensor connector.