Air Flow Meter/Sensor: Testing and Inspection

Fig. 25 Air flow meter terminal identification.:

1. Check air flow meter body for cracks or damage. Replace if necessary.
2. Measure resistance of air flow meter terminals, Fig. 25, as follows:

Fig. 4 Testing Air Flow Meter:

a. Connect suitable ohmmeter,Fig. 4, between terminals E2 and VS Resistance should be 20-400 ohms.
b. Connect ohmmeter between terminals E2 and VC. Measured resistance should be 100-300 ohms.
c. Connect ohmmeter between terminals E2 and VB. Resistance values should be 200-400 ohms.
d. Connect ohmmeter between terminals E2 and THA (intake air temperature sensor). At ambient temperatures of (-)4°F, resistance values should be 10,000-20,000 ohms. At temperatures of 32°F, resistance should be 4,000-7,000 ohms. At temperatures of 68°F, resistance should be 2,000-3,000 ohms. At temperatures of 104°F, resistance should be 900-1,300 ohms. At temperatures of 140°F, resistance should be 400-700 ohms.
e. Connect ohmmeter between terminals E1 and FC. Ohmmeter should read infinity.

Fig. 3 Exploded View, Air Flow Meter:

3. Check operation of measuring plate, Fig. 3 as follows:
a. With measuring plate closed, check resistance between terminals E1 and FC (fuel pump switch). Ohmmeter should read infinity. Fully open plate with a screwdriver, then observe ohmmeter. Resistance should be 0 ohms.
b. With measuring plate closed, check resistance between terminals E2 and VS. Resistance should be 20-400 ohms. Fully open plate as described above and observe ohmmeter. Resistance should be 20-1,000 ohms.