Air Flow Meter

MPI only

PROCEDURE

Slide back the rubber boot of the air flow meter, leave the connector connected.

Connect a precision voltmeter from the rear to the connector terminals, as shown in the diagram:
Measurement 1: connect the jumper wire to terminals 2 and 3. Turn the ignition on.

The voltmeter should read 12 – 14 V. Otherwise, the fuel supply is faulty.

Check fuse No. 27; if necessary, check the wire from fuse No. 27 to terminal 3 of the air flow meter connector.

Or check the connection to engine ground (terminal 2).

Measurement 2: connect the jumper wire to terminals 2 and 4.

Switch on the ignition.

The voltmeter should read 1.0 – 7.5 V. Otherwise, there is a fault in the CO potentiometer of the air flow meter. Replace the air flow meter.

Measurement 3: connect the jumper wire to terminals 1 and 2.

Switch on the ignition.

The voltmeter should read 0.3 – 1.1 V.

Start the engine (leave the jumper wire connected). Switch off all electrical consumers and make sure the cooling fan is not running.

Continuously vary the engine speed between idle and 4000 rpm.

The voltmeter should show (depending on engine speed) between 1.5 and a maximum of 3.4 V. Otherwise, the air flow meter is faulty. Replace it.