The mass airflow sensor is a key sensor in your car. Your car has a lot of sensors, and this is just one that helps your car run properly.
That brings up the question of can your car run without the mass air flow sensor?
In this article, we will look at what happens when you disconnect the mass airflow sensor. Read on to find out all you need to know about when you unplug your mass airflow sensor and if your car will stay running or not?
Contents
Before going into detail on what will happen when you disconnect the mass airflow sensor it is important to understand what it actually does. If you want a technical definition of how a mass airflow sensor works, then you can take a look at the article we have here, but for this article, we will just cover the basic function of the mass airflow sensor.
The basic purpose of the mass airflow sensor is to measure the amount of air that is going into the engine so your car can release the proper amount of gas into the engine, so the car is able to run correctly.
So, since the mass airflow sensor is used to measure air intake into the engine to keep the car running correctly, then what will happen if you unplug the sensor? Will the car die or stop running?
Well, the answer to that is no. If you disconnect the mass airflow sensor, then the car should keep running and still be able to start normally.
This is because the computer in the car if it does not receive a reading from the mass airflow sensor, will estimate and supply a number that it thinks it is supposed to have. This means that if your mass airflow sensor dies completely, then your car will stay running and surprisingly the car might run better without the mass airflow sensor. That is because if the sensor is bad or giving a wrong reading, then the cars guess might be closer to the actual amount of air that the engine is getting giving you a more accurate fuel mixture.
So, why might you want to disconnect the mass airflow sensor and drive around like that?
Well, the main reason is to test the mass airflow sensor and see if it is working right.
As has been mentioned by driving without it you might get better gas mileage and if that is the case, then it is a sign that you should clean or replace your mass airflow sensor because it is giving false readings.
On top of testing the mass airflow sensor by disconnecting it, you can also test some of your vehicles other sensors by disconnecting the mass airflow sensor.
If the car dies when you disconnect the mass airflow sensor, then that means it was working right and that your computer has issues.
It isn’t able to use the tables programmed in it to guess the amount of fuel needed. Also, if the computer isn’t the issue, then it means one of the other sensors is probably off if the car isn’t able to keep running without the mass airflow sensor because the sensor was helping the car compensate for the other issues that it was having. So as you can see disconnecting the mass airflow sensor is actually a good way to test a variety of things.
So, now that you know the reasons for unplugging the mass airflow sensor, the next question is when you should do it?
Well, the answer to that is pretty easy. Whenever your car is running rough, backfiring, or seeming to have issues with the fuel mixture, it is a good idea to unplug the mass airflow sensor. You can drive your car a bit and see if it runs correctly with the sensor disconnected.
If it does, then you know it was that sensor. If it doesn’t, then you know you need to look at one of the other sensors.
If it was the mass airflow sensor that is working improperly, then the first thing you should do to it is to clean it.
We have a guide here on how to clean it, but cleaning your mass airflow sensor is really easy and can help it start working correctly.If cleaning the mass airflow sensor does not fix the issues that it was having, then it is time to replace it. Sometimes mass airflow sensors get shorted or stop working and need to be replaced.
Once you have driven your car enough to test the mass airflow sensor it is a good idea to plug it back in or replace it after you are done testing. This is because it will help you get the best gas mileage possible.
That is because even though your car can run without the mass airflow sensor, you shouldn’t do it for long periods. That is because the numbers the computer generates are for brand new engines, and conditions change with the engine as it ages. By letting the mass airflow sensor make the readings, it allows for the most accurate numbers if it is working properly.
So, now you know what happens when you disconnect the mass airflow sensor. You know that your car will start and keep running even with the mass airflow sensor unplugged. In some cases, the vehicle might run even better if the mass airflow sensor is bad.
On top of knowing what happens though when you disconnect it, you also know why you might want to disconnect it and also when to disconnect it. You know unplugging your mass airflow sensor is a good way to test it and other sensors, but you also know that driving a bunch with it unplugged isn’t good because it gives more accurate readings than just your computer guessing at the airflow.
Now you know all you need to know about what will happen when you remove your mass airflow sensor from your vehicle.
my 1995 ford f 150 ran like shit.. spitting sputtering ..loss of power poor gas mileage and a lot of jerking when trying to shift...did some research on computer and it led me to mass airflow sensor after replacing everything else... drove to autozone replaced sensor in parking lot... imidiatley fixed all problems and now truck runs like a new truck.. amazing what a diffrence it made....
Congrats
You are doing rely good
It is mentioned up above, regarding the MAF sensor, if the sensor is unplugged/disconnected and the vehicle dies that the sensor is operating properly so that means there is computer issues. That is not 100% true fact so don't automatically think your computer is screwed up. Move down the line a little bit and check the throttle body, there is always the possibility of foreign object lodge causing issues or it may just need a good cleaning.
thank you for the info, gives driver better understanding about the car,,also lets us know when mechnics are not truthful.. (Whats New?)..
My 1994 Ford Aerostar Van with 158,000 miles is running OK Without the MAFS. Then why do I have to replace the sensor. Cleaning the sensor did not do any good.
What damages to the Van may happen if I ran the Van without MAFS.
Is there a way to find out if the EGR valve is bad instead of the MAF sensor? I replaced the MAF sensor and it ran fine but then the engine light came on just like it did before I replaced it. If I unplug the MAF, is there anything to look for to let you know it is the EGR valve?
Any help is much appreciated...
Thank you for the article. I am driving my Vw vento 1995 model with disconnected MAF sensor but it is hesitant to accelerate when engaged in travelling gears that is from gear number 3 upwards, though it rarely responds well. Can it be merely the priblem of MAF sensor only or it now involves fuel pump?
Thank you for this valuable info. I have a VW that only starts when i give a lot of gas. After that it runs normal. So i disconnected the MAFS and then it starts normal. It does however not idle smooth.
Does this mean the MAFS is defect for sure? Or can it still be something else?
I have a 2008 Toyota rav4 that's running like shit. Thought it was the MAF but car will not run or start when I disconnect MAF. How can I check other sensors? Any help will be greatly appreciated!
~Steph
07 Lexus ES350. Car is running lean (LTFTs reach 22%) but no check engine lights for it. Been trying to figure it out. Also hard starts sometimes. Car has had new spark plugs, battery, new downstream O2s, repaired a torn fuel vapor line, new egr valve, new gasket for oil cap. I decided to unplug the maf like you wrote,and the engine dies if I try to start it. Repeatedly. Mechanic didn't want to smoke test because he said his fuel trims weren't high when he scanned it...but they returned to 21-22% when I took the car back!