The MAF (Mass Air Flow) sensor is an important part of an engine’s fuel injection system without which many things will go wrong in the car such as; reduced gas mileage, sluggish acceleration, etc.
Although the MAF sensor is designed to last a long time, it can get bad due to various reasons. When this happens, the only option may be to have it replaced, after the MAF sensor has been replaced, how long does it take to work?
A new Mass air flow sensor will most likely work immediately provided it is installed correctly and also after the battery must have been disconnected for some minutes.
How Long Does It Take for a New MAF Sensor to Work?
All things being equal, a new MAF sensor should start work immediately it is installed.
Although a new MAF sensor can start work immediately it is installed, it is advisable that you allow the power in the engine to completely drain out.
By doing this, the engine is able to adjust itself to the new sensor by processing the new information it comes with.
To drain the engine of energy, you should remove the battery for at least 10mins before putting it back. Between this time, all energy should completely drain out of the engine.
When Should You Install a New MAF Sensor?
Usually, to install a new MAF sensor, certain miles between (20,000 – 25,000) must have been attained, however there are other ways to know it is time to install a new sensor.
When a sensor is bad, then you know it should be changed. Below are some symptoms of a bad MAF sensor that will require a sensor change:
1. Reduced Fuel Economy
When the mass air flow sensor is bad, there will be a reduction in gas mileage, this is because the sensor is unable to read correctly the amount of air that enters the engine, therefore, there will be an incorrect mixture of air and fuel.
If you notice there is a reduction in fuel economy, it may be time to change the MAF sensor, although this symptom could be related to other problems.
2. Check Engine Light On
When the check engine light comes on, it means there is a problem that needs checking out and fixing. To accurately detect the problem, you can use a scan tool.
In the case where the problem is with the MAF sensor, the error code will look something like this; P0100 to P0199. If you see either of this code, the MAF sensor needs fixing or replacement.
3. Engine Exhaust is Black
You will know it’s time to install a new MAF sensor when the engine exhaust is black. This is as a result of the sensor sending incorrect readings to the engine modules.
Incorrect readings to the module will result in more fuel in the combustion chamber which in turn causes more fuel to be burned. The result of excessive fuel burning is the black exhaust.
4. Difficulty when Accelerating
You should install a new MAF sensor when the car’s acceleration begins to lag and becomes sluggish, this can however be a result of other problems in the car.
A bad or faulty MAF sensor will send wrong air intake readings to the module resulting in an unbalanced mixture of air and fuel in the chamber, this in turn causes a lag in acceleration.
What to Do After Replacing Mass Air Flow Sensor?
After you must have replaced the MAF sensor, you can either allow the car to be idle to at least 30mins or disconnect the battery for at least 10 minutes.
The purpose of doing this is to allow the car’s computer to go back to its default settings and relearn the new parameters and information that comes with the new sensor.
Do I Need to Disconnect Battery When Changing MAF Sensor?
No, you do not need to disconnect the battery when changing MAF sensor. However, you can do so if you feel it will be safer for you.
With the engine off there is no power running through the battery therefore, it is safe to change the MAF sensor without disconnecting the battery.
However, it is recommended to always disconnect your battery before changing or removing your mass air flow sensor. For the couple of times I’ve personally changed my mass air flow sensor, I disconnected by battery before doing so.
Why Won’t My Car Start After Replacing Mass Air Flow Sensor?
Normally when a mass air flow sensor is replaced the car should start but there are instances where this is not the case, the car just won’t start.
If this happens, it probably means the car’s computer is unable to read the new parameters and information.
To remedy the situation, you will need to leave the car idle for some minutes or disconnect the battery. Doing any of this is a good way to allow the car relearn the new parameters and start.
If the car still won’t start after doing all that, then, it could be that the sensor you installed is bad. Install another different sensor and see if the car will start.
Rough Idle After Replacing Mass Air Flow Sensor
Rough idling means a car rpm keeps going up and down even after the mass air flow sensor is changed.
If a car keeps rough idling after mass air flow replacement, it could be that there is a leakage in the air intake system, a vacuum leak or the fuel pressure isn’t enough. It could also be that the ‘Barometric Pressure’ (BARO) sensor is faulty.
If you suspect any of the aforementioned proceed to check the intake plumbing and ensure they rightly positioned. You may also need to test the BARO sensor and ensure it is working fine.
How to Reset Check Engine Light After Replacing Mass Air Flow Sensor
Resetting the check engine light after the mass air flow sensor has been replaced is quite easy. Often times, when there is a mass air flow replacement, the check engine light will go off on its own after sometime but this does not happen all the time.
- To reset the check engine light after mass air flow sensor change, you will need to disconnect the battery starting with the negative terminal then the positive terminal.
- After the battery must have been disconnected, leave it out for at least 10mins. 10mins is enough time for the check engine light to go off provided nothing else is wrong somewhere in the car.
- Then you can proceed to reconnect the battery in the engine, in the same order it was disconnected.
Conclusion
If you have decided that replacing the mass air flow sensor is the best option, ensure that it is installed correctly, get an expert to do it. When a MAF sensor is not installed well, it is the same has not changing it because the car will not start.