Page 62 - E BOOK ENGINE MECHANICAL M2

4. SERVICE POINTS OF 4D56 ENGINE COMPONENT

1. ON-VEHICLE INSPECTION AND SERVICE

(1) Compression Pressure Check
1. Before inspection, check that the engine oil, starter
and battery are normal. In addition, set the vehicle to the
pre-inspection condition.
2. Remove the engine air intake pipe.
3. Remove the inlet manifold.
4. Remove all of the glow plugs.
5. Disconnect the crank angle sensor connector.

Note Doing this will prevent carrying out fuel injection.
Fig. 4-1
6. Cover the glow plug hole with a shop towel etc., and
after the engine has been cranked, check that no for-
eign material is adhering to the shop towel.

◆Keep away from the glow plug hole when cranking.
◆If compression is measured and water, oil, fuel, etc., are present as a result from cracks
Caution
in the cylinder, these materials will become heated during the cranking of the engine and
will gush out from the glow plug hole, which is dangerous.

7. Set the compression gauge to one of the glow plug
holes.
8. Crank the engine and measure the compression
pressure.
Standard value (at engine speed of 250 r/min):
2,400 kPa <High power engine>
2,500 kPa <Other than high power engine>

Limit (at engine speed of 250 r/min):
Min. 1,650 kPa <High power engine>
Fig. 4-2 Min. 1,750 kPa <Other than high power engine>
9. Measure the compression pressure for all the cylin-
ders, and check that the pressure differences of the cyl-
inders are below the limit.
Limit: Max 300 kPa
10. If there is a cylinder with compression or a compres-
sion difference that is outside the limit, pour a small
amount of engine oil through the glow plug hole, and
repeat the operations in steps 8 and 9.
(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.

11. Connect the crank angle sensor connector.
12. Install the glow plugs.
Tightening torque: 17 ± 2 Nm
13. Install the inlet manifold.
Note Install a new gasket.

4 - 1 Pub. No. PTAE1228