Question

Assignment:         Analyse and evaluate a faulty Mass Air Flow sensor.

1.         You will choose a vehicle with a MAF sensor that was produced after 1998.

2.         You must say what the fault is that has occurred (eg. MAF sensor voltage too high), and the DTC that would be logged.

3.         You must say what the symptom of this fault would be (what would the customer notice?).

4.         Show, using a diagram, how you would check the sensor. You must show what test equipment you would use AND how you would connect it to the sensor.

5. What are the correct readings you should see using the test equipment you have chosen?

6.         You must say what the Engine Management System would do if this fault occurred (ie. what is the failsafe?).

7.         You must say how this fault may have occurred and what can be done to make sure it doesn’t happen again.

Please do all the problems, above it is laboratory work. Please do ASAP. Please. I will give a high rating for this complete Solution. Thank You

Answer 1

From different types of sensors used in cars, The Mass Air Flow Sensor (MAF) is a computer-controlled sensor that calculates the volume and density of the air taken in by the engine. This in turn ensures the right amount of fuel is used for optimized operating conditions. If this sensor is faulty, the car may stall and the fuel usage will be higher than necessary.

3. Here are some of the most common symptoms of a faulty mass airflow sensor:

• The engine is very hard to start or turn over.
• The engine stalls shortly after starting.
• The engine hesitates or drags while under load or idle.
• Hesitation and jerking during acceleration.
• The engine hiccups.
• Excessively rich or lean idling.

5. MAF sensor output to the computer depends on the type of sensor used. The hot wire version, which Bosch introduced back in '79 on its LH-Jetronic fuel injection systems and is used on a number of multiport systems including GM's 5.0L and 5.7L Tuned Port Injection (TPI) engines, generates an analog voltage signal that varies from 0 to 5 volts. Output at idle is usually 0.4 to 0.8 volts increasing up to 4.5 to 5.0 volts at wide open throttle.

The hot film MAFs, which AC Delco introduced in '84 on the Buick turbo V6 and have since used on the 2.8, 3.0 and 3.8L V6 engines, produce a square wave variable frequency output. The frequency range varies from 30 to 150 Hz, with 30 Hz being average for idle and 150 Hz for wide open throttle.