does anyone have a walk through for compression testing the cylinders? i have the prssure gauge, just not 100% sure how to go about it.
cheers.

Basically its connect the gauge to a cylinder starting from 1 and record the maximum pressure it reads as you turn the engine over by hand. disconnect the crank angle sensor to prevent firing. do this on each cylinder, i cant remember the value specified by mitsi, but i do know they should be within a certain range. hope this helps a little!

how do u crank it by hand? and where can i find the crank angle sensor?
sorry abt the noobness

robssei means to disconnect the crank angle sensor, connect your compression tester into spark plug hole & turn the ignition key so the engine spins over a few times, without firing up! I think the crank angle sensor is located inside the distributor cap.. I'm still learning magnas but that's the most common location!

This is straight out of the workshop manual

COMPRESSION PRESSURE CHECK
1. Before inspection, check that the engine oil, starter and
battery are normal. Also, set the vehicle to the following
condition.
Engine coolant temperature: 80–95C
Lights and all accessories: OFF
Transmission: P range
2. Disconnect the spark plug cables.
3. Remove all of the spark plugs.
4. Disconnect the crank angle sensor connector.
5. Cover the spark plug hole with a rag, and after the engine
has been cranked, check that no foreign material is
adhering to the rag.
Caution
1. Keep away from the spark plug hole when
cranking.
2. Do not let water, oil, fuel, etc. enter the cylinder,
as these heated materials will gush out from the
spark plug hole, which is dangerous.
6. Set the compression gauge to a spark plug mounting
hole.
7. Crank the engine with the throttle valve fully open and
measure the compression pressure.
Standard value: 1200 kPa/250–400 r/min
Limit: min. 890 kPa/250–400 r/min
8. Measure the compression of all the cylinders, and check
that the pressure differences of the cylinders are below
the limit.
Limit: max. 100 kPa
9. 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 (6) to (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
leaking from the gasket.
10. Reconnect the crank angle sensor connector.
11. Reinstall the spark plugs and spark plug cables.
12. Use the MUT–II to erase the diagnosis codes, or
disconnect the negative battery cable for 10 seconds
or more and then re-connect it.
NOTE
This will erase the diagnosis code resulting from the crank
angle sensor connector being disconnected

Disconnecting the battery will probably mean a re-learn procedure for the Transmission computer and engine idle may also go low and usually needs to be reset by leaving the car idle for a while with no accessories running.

Link for manuals http://www.aussiemagna.com/forums/showthread.php?t=56815