Is it possible the MAF could be the issue, but not throwing codes?

 

Disconnect maf sensor to check idle quality(it will throw a code when disconnected, just clear after you observe)

 

When I pulled it, it died.

 

Before you start it.

 

Solved! So hours of diag time last night. Went through testing of the coil harness. Turns out chassis ground(black wire) of the coil harness had mass quantities of resistance. Thats actually a pcm ground. Found that 3 out of 4 main grounds on the truck were really really bad. Clean everything up and re-tested. Ran better than it ever has but still had misfire on cyl4. Again no codes. Triple checked all of it again. Bad plug! Ngk platinums. In all the years ive been doing this ive never had issues with these plugs, but i guess when you have a numerous main ground issues it could burn a plug up. Anyway. Getting new plugs today, should be good to go. Thanks for all your comments.

 

Yea I pulled it before I started it. It started, but quickly died. I have a 2008, maybe that's why? I'm going to clean my MAF and change the air filter. I also changed my tune to run 87, but I think i'm going back to 93 octane. I read the 6.2's need to run premium.

 

In my experience the later GM LS engines we have also seem to do the best with the factory spec ACDelco spark plugs.... Granted, there is a possibility that NGK makes them for GM but not necessarily.

 

So seems like I resolved my issue. Filled up with 93 octane, added an octane booster(since i had half a tank of regular), cleaned my MAF, and changed my tune back to 93.

 

What Happens If You Disconnect Mass Air Flow Sensor?

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?



What Happens If You Disconnect Mass Air Flow Sensor?
What does Mass Air Flow Sensor do?

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.

What Happens If You Disconnect Mass Air Flow Sensor?

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.

Why disconnect the mass airflow sensor?

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.

Like 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.

Another way to test your MAF is using best obd2 scanner, it will find the error in your Mass Air Flow Sensor.

When should you disconnect the mass airflow sensor?

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.

Conclusion

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.

 

Mr David Paige, the hummer h2 was not manufactured with AFM, you may have had bad lifters but it was not due to AFM

Neal