1. Before starting the test, check the condition of the engine oil, starter and battery. Prepare your vehicle for inspection (warm up the engine to normal operating coolant temperature).
2. Disconnect high voltage wires from spark plugs.
3. Remove all spark plugs.
4. Disconnect the 6-pin connector from the ignition distributor (SOHC) or crankshaft position sensor connector (DOHC).
Attention! This measure will prevent fuel injection and ignition commands from the ECM (ECU).
5. Plug the spark plug holes with a clean rag and after turning the crankshaft with the starter, check for foreign particles on it.
Attention! Keep clear of the spark plug holes while cranking the crankshaft with the starter. If, during a compression test, the cylinder gets (as a result of cracks) coolant, oil, fuel, etc., they will heat up and be ejected under pressure from the spark plug hole - this is dangerous.
6. Install a compression gauge in the spark plug hole.
7. The assistant should press the accelerator pedal to the stop and turn the engine with the starter. After cranking the crankshaft one or two revolutions, the compression pressure should increase to maximum and then stabilize.
8. Measure the compression in all cylinders and check that the difference in compression values between the cylinders is no more than 100 kPa.
9. Pay attention to the fact that the compression of a serviceable engine should increase rapidly. Low compression on the first revolution of the crankshaft, followed by a gradual increase in pressure on subsequent revolutions, indicates worn piston rings.
10. Low compression on the first revolution of the crankshaft, which increases slightly thereafter, indicates a loose fit of the valves, a damaged cylinder head gasket, or the presence of a crack in the block head. Worn valve stem ends can also lead to low compression.
11. If in any cylinder the compression exceeds the maximum allowable value or the difference in compression values between the cylinders exceeds the maximum allowable value, pour a little engine oil into the spark plug hole of this cylinder and repeat the compression measurement.
12. If after oil filling the compression has increased, then the causes of the malfunction are wear or damage to the piston ring and / or cylinder mirror.
13. If after oil filling the compression does not increase, then the reasons are burnt or damaged valve seat or gas leakage (pressure) through the cylinder head gasket.
14. Low compression in two adjacent cylinders indicates a burnt gasket between the cylinders.
15. If the compression in one cylinder is less than 20% than in the others, and the engine is unstable at idle, this indicates a worn camshaft cam.
16. If the compression pressure is too high, this indicates that the combustion chamber is covered with a thick layer of soot.
17. Connect a socket of wires to the distributor of ignition.
18. Screw spark plugs and connect high-voltage wires to them.
19. Use MUT-II to clear the DTC.
Attention! This operation will erase from the memory of the electronic control unit the fault code resulting from the disconnection of the connector from the ignition distributor.