COMPRESSION PRESSURE CHECK


1.Before inspection, set the vehicle to the pre-inspection condition.
2.Disconnect the ignition coil connectors and then remove all of the ignition coils and spark plugs.
note Do not disconnect the injector connectors.
3.Connect the ignition coil connectors.
caution
  • Keep away from the spark plug hole when cranking.
  • If compression is measured with water, oil, fuel, etc., that has come from cracks inside the cylinder, these materials will become heated and will gush out from the spark plug hole, which is dangerous.

4.Cover the spark plug hole with a shop towel etc. Select item No. 4 (Engine compression measurement) from Test of PHEV-ECU special function on the M.U.T.-III. Crank the engine, and then check that no foreign material is adhering to the shop towel.

5.Set compression gauge to one of the spark plug holes.
6.Select item No. 4 (Engine compression measurement) from Test of PHEV-ECU special function on the M.U.T.-III and measure the compression pressure.

    Standard value (at engine speed of 300 r/min): 1,440 kPa

    Limit (at engine speed of 300 r/min): Minimum 1000 kPa
7.Measure the compression pressure for all the cylinders, and check that the pressure differences of the cylinders are below the limit.
Limit: Maximum 98 kPa
8.If there is a cylinder with compression or a compression difference that is outside the limit, pour a small amount of engine oil through the spark plug hole, and repeat the operations in steps from 5 to 7.
(1) If the compression increases after oil is added, the cause of the malfunction is a worn or damaged piston ring and/or cylinder inner surface.
(2) If the compression does not rise after oil is added, the cause is a burnt or defective valve seat, or pressure is leaking from the gasket.
9.Install the spark plugs and ignition coils.
10.If the diagnosis code is stored during the check, use the M.U.T.-III to erase the diagnosis codes.