When to Call the Saab 900 Air Mass Meter a Dud
An air mass meter, commonly known as mass air flow sensor or MAF for short, is used to find out the rate ofair flowentering the combustion chamber of afuel-injected engine. The information procured by this component is necessary for theengine control unit(ECU), the engines onboard computer, to balance and deliver the correct fuel flow to the engine. Therefore, the air/fuel mixture ratio is always at the optimum. Now, the air mass meter could go wrong at any time and this will mess up the process inside the engine. Here are some common signs that indicate a defective air mass meter.
Check engine indicator lights up
Like most defective sensors found inside the engine, they communicate with the ECU to actuate various processes. Once there's something wrong with them, they send a signal also to the ECU and it reflects as a lit check engine light on the dashboard. This is the most reliable symptom of a failing or failed air mass meter. However, since a lot of other parts can set this illumination off, further test should be taken into consideration.
Error codes from scanner
With the car getting more and more technologically savvy, even specific part failures can be detected and diagnosed within minutes with accuracy. An auto diagnostics scanner that's found in most car shops or mechanics near you can do this. Since computer communicates through codes and numbers, any code, number, or message pertaining to a bad air mass meter in your car must be translated properly using the code interpreter found in the owner's manual. The only downside to this one is it comes with a fee. However, if you have invested a diagnostic scanner yourself, then taking a look at what's wrong in your air mass meter is easy. If the scanner codes refer to a malfunctioning air mass meter, you will need to have it inspected right away.
Because the air mass meter is an integral instrument behind the correct balance of air and fuel inside the engine, its failure can cause a range of engine performance problems. These may include low fuel efficiency and dropped gas mileage, stalling, misfiring, knocking or pinging. These are common indicators of failure in automobile parts and are not exclusive specifically to air mass meter failure. Although, these symptoms can appear before the air mass meter fails and the check-engine light will register a problem.
Ensuring Smooth Air Flow with Your Saab 900 Air Mass Meter
An air mass meter monitors the air coming in through the air intake system so that the combustion inside the engine will always result to the most favorable air/fuel ratio. The ratio will always vary under different circumstances. Therefore, adjustments to the fuel mixture are necessary to keep a vehicle running smoothly. Too much or too little of either air or fuel will cause the engine to run lean or rich, depending on the difference. This will make the car stall, be less fuel efficient, and produce dirty emissions. When the air mass meter fails to achieve this perfect ratio, your vehicle will have a hard time running smoothly. Hence, a good measure of preparation and preemptive action is key to maintaining a good air mass meter. Here are some things you can do.
Testing the air mass meter
Doing an occasional test is a good way to be on tabs with how far along your air mass meter is going. Since it is operated electronically, a multimeter is to be used for this kind of test. Just turn the ignition on without starting the engine so electricity flows through the components. Then connect the multimeter's (set to read resistance in ohms) positive probe on the air mass meter marked as "SIG" while doing the same with the negative probe on the "GND" terminal. If the reading indicates an infinite resistance or an open circuit, the air mass meter is damaged and needs to be replaced.
Testing the power supply
The same thing is to be done with the earlier test at the beginning. The location of the air mass meter and its electrical connector must be determined in order to test the power supply. This time a voltmeter must be used to join the probes with the disconnected electrical connectors. The negative probe goes to the sensor's GND terminal and the positive probe to the terminal indicated as "B+". A zero reading indicates the absence of the electrical output or enough electrical input from the ECU. This won't make the air mass meter function well because there should always be uninterrupted voltage sent to the air mass meter.
Cleaning the air mass meter
Cleaning the meter ensures that no other foreign material may impede its function. You can unscrew the meter and spray away any debris from the meter using an electronic part cleaner. Also, if you see any corrosion in the screws, replace them with new ones. For a thorough clean, put the air mass meter inside a bag filled with isopropyl rubbing alcohol. Shake the bag and allow the meter to sit for 20 minutes before drying it with a towel. Leave it to dry for 45 minutes.