Pinpoint Test A: Check The Cylinder Compressions

WARNING: Only compression testers able to read the higher compression pressures found in diesel engines should be used. Failure to follow this instruction may result in personal injury.

NOTE: Where possible, compression testing should be carried out on an engine at operating temperature.

TEST CONDITIONS	DETAILS/RESULTS/ACTIONS
A1: CARRY OUT A DRY CYLINDER COMPRESSION TEST
	1 Make sure the parking brake is applied and that the selector lever is in park.
	2 Set the ignition status to OFF.
	3 Remove the starter relay.
	4 Disconnect the starter motor solenoid connector.
	5 Connect a suitable remote starter device to the starter motor solenoid.
	6 Remove the glow plugs.
	7 Install adaptor 303-1131 in place of the glow plug in the first cylinder to be tested.
	8 Connect a suitable compression tester to the adaptor. See warning above.
	9 Using the remote starter device, crank the engine a minimum of five revolutions.
	10 Record the compression figure and the number of revolutions taken to reach it.
	11 Repeat steps 7 - 10 above for the remaining cylinders, cranking the engine for a similar number of revolutions each time.
	12 Compare the compression figures across all the cylinders.
	Are the compression figures within 10% of each other? Yes Unless the compression figures are universally very low (experience will indicate this), check for other causes for the customer complaint. No GO to A2.

TEST CONDITIONS	DETAILS/RESULTS/ACTIONS
A2: CARRY OUT A WET CYLINDER COMPRESSION TEST
CAUTION: If engine oil is introduced into the cylinders, run the engine at 2, 000 rpm for a minimum of ten minutes after completing testing to prevent damage to the catalytic converters. Failure to follow this instruction may result in damage to the vehicle.
NOTE: There is a combustion chamber in the top of each piston. Make sure that the oil is not allowed to run into this chamber.
	1 Using a suitable oil can with a flexible spout, introduce a small amount of clean engine oil into the cylinder just before testing, such that the oil is able to run between the piston and the cylinder bore.
	2 Repeat steps 7 - 10 from the test above, introducing oil into each cylinder just before testing.
	3 Compare the compression figures across all the cylinders
	Is the compression figure higher than the dry test? Yes A higher figure following the introduction of oil may indicate a worn or damaged cylinder bore, piston and/or piston rings. Disassembly would be required to confirm this. No If the compression figure is unaffected by the introduction of oil, but the figure is still less than 90% of the other cylinders, this may indicate a burnt and/or sticking valve, leaking head gasket, etc. Disassembly would be required to confirm this. Clear any DTCs which may have been induced by the test.