Checking the fuel injectors

Right: The illustration shows the connector (1) disconnected from the fuel injector (2). A LED voltmeter can be used to check whether the power supply to the fuel injectors is in order.

A LED voltmeter is required for electrical checks.

PROCEDURE

Power supply check: disconnect the connectors from the fuel injectors one at a time.

Connect the voltmeter to the contacts of the disconnected connector.

An assistant must start the engine.

The LEDs should flicker; otherwise there is a fault in the injector wiring or the control unit itself is faulty.

Injector check: disconnect all connectors from the fuel injectors.

Connect the ohmmeter to both connector contacts of the first fuel injector.

Specified value: 15–20 ohms.

Repeat the check on the other injectors.

More detailed check (leak tightness/spray pattern)
Remove the fuel injectors together with the fuel distributor pipe – see the procedure later in this chapter.

However, the wire connectors must remain connected and the fuel hoses must remain attached.

On the left, in the coolant pipe, disconnect the connectors of the start valve and the temperature sensor.

Direct the fuel injectors into four measuring containers.

Now an assistant must crank the engine with the starter for several seconds: the spray pattern must be the same for all four injectors. In this case, the spray pattern is correct.

Disconnect the central connector of the fuel injectors in the cable duct.

Switch off the ignition, then switch it on for 5 seconds: no more than two drops should emerge from each injector. In this case, the injectors are leak-tight.