Checking injection valves (injectors)

The injection valves inject fuel intermittently, i.e., one revolution of the crankshaft injects half of the fuel required for one intake stroke. In this case, the valve injects fuel in the form of a cone, and after spraying it closes tightly. Faulty injection valves cause the engine to continue running after the ignition is turned off and cause engine misfiring.

Checking work

1. Leave the engine to idle.

2. Check each valve with the engine running with a stethoscope to see if it clicks. These clicks are caused by the valve opening and closing.

3. If a stethoscope is not available, you can check the operation of the valve with a screwdriver or your finger.

4. If there is no noise from operation or it has an unusual character, check the plug connection, the signal from the control device (performed in the workshop) or resistance.

Resistance test

1. Turn off the ignition.

2. Disconnect the injection valve plugs.

3. Measure the resistance of all injection valves at the connectors with an ohmmeter.

Required value: (all engines) 12-16 ohm.

4. If the value is not correct, the injection valve must be replaced.



5. To check the injection jet and the tightness of the valve, special tools are needed, available from MAZDA original workshops.