Compression measurement

1. Before measuring, warm up the engine to operating temperature. Thanks to this, all moving parts will come into working condition.
2. Disconnect the ignition terminals (terminal 15), disconnect the spark plug connector and remove all spark plugs.
3. Set the handbrake, set the gearshift lever to idle, press the clutch and accelerator pedals.
4. Press the rubber cone of the pressure controller against the spark plug hole (in diesel to the injector nozzle) the first cylinder - if necessary, use a suitable adapter.
5. The assistant cranks the engine using the starter about 6-8 times. The maximum pressure has been reached. An important point for carbureted engines: the best filling with fresh fuel mixture (external mixture formation) only achieved when the accelerator pedal is fully depressed.
6. Read the measurement reading and record. If you have a device with a recorder (data storage) switch it to the next cylinder.
   
   

7. The rubber cone of the compression tester should tightly cover the spark plug hole. At your command, the assistant starts the starter. The starter should be turned until the instrument pointer is in the rest position.

   
   

   Repeat the measurement process on all four cylinders in the row. It is important that the absolute value of the pressure is the same in all cylinders.

Compression pressure reduction

• in the intake manifold or intake silencer - a leaky intake valve.
• from an open radiator or coolant expansion tank - a defective cylinder head gasket or cracks in the cylinder head.
• from an open oil filler neck or oil level indicator - worn cylinder walls, cylinder sliding surfaces or piston rings.
• in the exhaust pipe - a leaky exhaust valve.