Air Flow Meters

Air Flow Meters

Air Flow Meters First Generation 1UZ 5 Volt

AFM 5 Volt Lexus V8

Air Flow Meter for first generation 1UZFE Lexus V8 engine

PURPOSE The air flow sensor accurately measures the amount of air entering the engine. LOCATION Mounted to the air cleaner on the right side of the engine compartment. CONSTRUCTION The Karman-Vortex style air flow sensor is built quite differently than conventional air flow sensors. Inside the sensor housing is a LED, a photo transistor and a spring mounted mirror. OPERATION Light from the LED shines onto the mirror portion of the sensor. As light is reflected off of the mirror, it is output by the photo transistor as a voltage. As air flow increases through the sensor, vortices in the air flow exert pressure on the mirror. Because the vortex created in the sensor is not constant, the force on the mirror occurs as vibrations. When the mirror vibrates, light from the LED striking the photo transistor reflects the vibrations. The vibrations are converted to a voltage signal and fed to the ECU.

Air Flow Meters Second Generation 1UZ 12 Volt

Lexus V8 12V AFM

Air Flow Meter for 95 Lexus V8

AFM For 95 workings

Air Flow Meter for Lexus v8 95 Model workings

The mass air flow meter uses a platinum hot wire. The hot wire air flow meter consists of a platinum hot wire, thermistor and a control circuit installed in a plastic housing. The hot wire air flow meter works on the principle that the hot wire and thermistor located in the intake air bypass of the housing detect any changes in the intake air temperature. The hot wire is maintained at the set temperature by controlling the current flow through the hot wire. This current flow is then measured as the output voltage of the air flow meter. The circuit is constructed so that the platinum hot wire and thermistor provide a bridge circuit, with the power transistor controlled so that the potential of (A) and (B) remains equal to maintain the set temperature.

Air Flow Meters Third Generation 1UZ

AFM For 99 Ls400 Lexus V8

AFM For 99 Ls400 Lexus V8

CIRCUIT DESCRIPTION 
The mass air flow meter uses a platinum hot wire. The hot wire air flow meter consists of a platinum hot wire, thermistor and a control circuit installed in a plastic housing. The hot wire air flow meter works on the principle that the hot wire and thermistor located in the intake air bypass of the housing detect any changes in the intake air temperature.
The hot wire is maintained at the set temperature by controlling the current flow through the hot wire. This current flow is ten measured as the output voltage of the mass air flow meter.
The circuit is constructed so that the platinum hot wire and thermistor provide a bridge circuit, with the power transistor controlled so that the potential of A and B remains equal to maintain the set temperature.

Air Flow Meters Forth Generation 1UZ VVT Front harness and 3UZFE engines

Air Flow Meter for 3UZ

AFM 12V 3UZ 1

INSPECT MASS AIR FLOW  METER RESISTANCE Using an ohmmeter, measure the resistance between terminals THA and E2.

3UZ AFM Resistance Value

Air Flow Meter Resistance for 3UZ

If the resistance is not as specified, replace the mass air flow (MAF) meter.

Afm for 3uz checking

Checking AFM for 3uz engine

INSPECT MASS AIR FLOW (MAF) METER OPERATION

    1. Connect the mass air flow (MAF) meter connector.
    2. Turn the ignition switch ON.
    3. Using a voltmeter, connect the positive (+) tester probe to terminal VG, and negative (-) tester probe to terminal E2G.
    4. Blow air into the mass air flow (MAF) meter, and check that the voltage fluctuates. If operation is not as specified, replace the mass air flow (MAF) meter.
    5. Turn the ignition switch LOCK.
    6. Disconnect the mass air flow (MAF) meter connector.

INSTALL MASS AIR FLOW (MAF) METER

    1. Install a new O-ring and the mass air flow (MAF) meter with the 2 screws.
    2. Connect the mass air flow (MAF) meter connector.
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