1. Before starting the test, check the condition of the engine oil, starter and battery. Prepare the car for testing (warm up the engine to normal operating temperature of the coolant).
2. Disconnect the high-voltage wires from the spark plugs.
3. Remove all spark plugs.
4. Disconnect the 6-pin connector (SOHC) or crankshaft position sensor connector (DOHC) from the ignition distributor.
Caution: This measure will prevent the engine control unit (ECU) from issuing fuel injection and ignition commands.
5. Plug the spark plug holes with a clean rag and after turning the crankshaft with the starter, check for foreign particles on it.
Caution! When turning the crankshaft with the starter, stay away from the spark plug holes. If coolant, oil, fuel, etc. get into the cylinder (as a result of cracks) during the compression measurement, they will heat up and be ejected under pressure from the spark plug hole - this is dangerous.
6. Install the compression gauge into the spark plug hole.
7. The assistant should press the accelerator pedal all the way down and turn the engine over with the starter. After turning the crankshaft one or two revolutions, the compression pressure should increase to the maximum and then stabilize.
8. Measure the compression in all cylinders and check that the difference in compression values between cylinders is no more than 100 kPa.
9. Note that the compression of a healthy engine should increase rapidly. Low compression on the first revolution of the crankshaft, followed by a gradual increase in pressure on subsequent revolutions, indicates wear of the piston rings.
10. Low compression on the first revolution of the crankshaft, which increases slightly later, indicates loose valves, damaged cylinder head gaskets, or a crack in the cylinder head. Worn valve stem ends can also cause low compression.
11. If the compression in any cylinder exceeds the maximum permissible value or the difference in compression values between cylinders exceeds the maximum permissible value, pour some engine oil into the spark plug hole of that cylinder and repeat the compression measurement.
12. If the compression has increased after adding oil, the cause of the malfunction is wear or damage to the piston ring and/or cylinder bore.
13. If the compression does not increase after adding oil, the cause is a burnt or damaged valve seat or a gas (pressure) leak through the cylinder head gasket.
14. Low compression in two adjacent cylinders indicates a burnt-out gasket between the cylinders.
15. If the compression in one cylinder is 20% less than in the others, and the engine idles rough, this indicates a worn camshaft lobe.
16. If the compression pressure is too high, this indicates that the combustion chamber is covered with a thick layer of carbon deposits.
17. Connect the wire connector to the ignition distributor.
18. Screw in the spark plugs and connect the high-voltage wires to them.
19. To clear the fault code, use MUT-II.
Caution: This operation will erase from the memory of the electronic control unit the fault code that occurs as a result of disconnecting the connector from the ignition distributor.