Manifold Vacuum Check - Mitsubishi 4G6 Manual

11A-10
Compression gauge
ENGINE <4G6> -
6. Set compression gauge to one of the spark plug holes.
7. Crank the engine with the throttle valve fully open and
8. Measure the compression pressure for all the cylinders,
9. If there is a cylinder with compression or a compression
10. Connect the crank angle sensor connector.
11. Install the spark plugs and spark plug cables.
12. Use the MUT-II to erase the diagnosis codes.

MANIFOLD VACUUM CHECK

Vacuum gage
1. Start the engine and allow it to warm up until the
2. Connect a tachometer.
3. Attach a three-way union to the vacuum hose between
4. Start the engine and check that idle speed is within
On-vehicle Service
measure the compression pressure.
Standard value (at engine speed of 250 - 400 r/min):
1,400 kPa
Limit (at engine speed of 250 - 400 r/min):
Min. 1,060 kPa
and check that the pressure differences of the cylinders
are below the limit.
Limit: Max. 100 kPa
difference that is outside the limit, pour a small amount
of engine oil through the spark plug hole, and repeat
the operations in steps 7 and 8.
(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.
NOTE
This will erase the diagnosis code resulting from the crank
angle sensor connector being disconnected.
temperature of the engine coolant reaches 80 to 95_C.
the fuel pressure regulator and the air intake plenum,
and connect a vacuum gauge.
standard value. Then read off the vacuum gauge.
Limit: Min. 69 kPa
11100270409