Thread: Mass airflow sensor troubles!

Easy MAF troubleshooting... unplug it. It forces the PCM to rely on other sensors. If the car still acts up, it's something else. If not, you found your issue.

With the MAF unplugged, some cars will die at first when idling. Just start it back up as it learns then go for a drive.

I'm going to say it's probably not a faulty MAF sensor. When my MAF sensor went bad, the car wouldn't even run.

Originally Posted by Deezul_AwT

I'm going to say it's probably not a faulty MAF sensor. When my MAF sensor went bad, the car wouldn't even run.

I'll agree with that as that is sometimes the case, but for some reason, whatever that may be, some cars can run without it plugged in. It may not be real pretty, but it will run and idle.

Originally Posted by SyntheticShield

I'll agree with that as that is sometimes the case, but for some reason, whatever that may be, some cars can run without it plugged in. It may not be real pretty, but it will run and idle.

Mine ran without it plugged in, but it either ran without it plugged in, or did not run with it plugged in. It didn't "run bad" with it in - it didn't run period. So if it's plugged in and running, I'm thinking it's not the MAF sensor.

I troubleshot a Grand Prix GTP in Kansas not long after joining the community. Drove up there to help the guy out and took my scanner. We made a few runs and everything ran perfectly. However, performance was notably off, not really sluggish or anything but it didnt accelerate like it should have.

I monitored the MAF readings to see what his air flow was like and the values never changed, it registered only minimum air flow like it would around idle and once he was into the upper RPM range there would be several degrees of KR.

No matter where the gas pedal was it registered the same air flow rate. I swapped it out with mine and everything ran perfectly and as it should and the KR dropped to around 1 - 2* of KR.

He got a new MAF and all was well again. There were no real indications the MAF was dead, it never even set the SEL light, the only indication was the performance was definitely not what it should be. So they can run with the MAF being faulty and plugged in, and my experience in dealing with this sort of issue is that each car seems to respond a bit differently. There are the 'normal and typical' symptoms that seem to apply to 'most' cars but there is also those that buck that all together and it takes a bit of diagnosis to isolate.

Nope, despite your long and thorough explanation, I'm right and you're wrong.

You crack me up. I guess I'll just have to admit it and be done with it.

Originally Posted by SyntheticShield

I'll agree with that as that is sometimes the case, but for some reason, whatever that may be, some cars can run without it plugged in. It may not be real pretty, but it will run and idle.

It's not magic. The car uses the VE table, MAP sensor, and TPS to determine how much fuel should be used. Once in closed loop mode it can further fine tune this fueling with the O2 sensor.

Every car should run without the MAF sensor, as that's why the VE table even exists (in case of MAF failure and to give the PCM a baseline on the efficiency of the engine).

Originally Posted by Sabrewings

Every car should run without the MAF sensor, as that's why the VE table even exists (in case of MAF failure and to give the PCM a baseline on the efficiency of the engine).

Yes, I know it will run without the MAF sensor; that's how I figured out what was bad on my GP. But you do notice it running a bit rougher when it's not connected. It just doesn't seem "right."

Originally Posted by turbobeetle

Hey ppls...

I'm new to the forum, I don't usually join them. I was compelled to join this one for two reasons, I've resorted to using it a couple times and have always been able to find what I've been looking for and, two, DeeZul rocks!

So yes... I have to agree with him.

Thanks!

Originally Posted by turbobeetle

I went out and unplugged my MAF sensor. The car ran completely fine. Not an issue. So I will go to the dealer tomorrow and replace the one I have... I may in the meantime pull the code for the SES light and see what it has to say. The light came on tonight and the car has been acting up since August...

Thanks for helping out guys.

DJ.

After market MAF is $120 at Autozone or Advanced. Dealer will probably charge $180, plus 30 minutes of labor. Go buy it yourself and repair it yourself. Heck for the money you'd save you could pick up a Haynes manual that will show you how to do it. 5 minutes tops. Don't pay a dealer to change it out, unless you've got a warranty that will cover it.

i believe my MAF sensor is out, and my car has no SES light or anything.
runs fine through town, but getting onto the highway when you get on it there is a light smoke behind the car (white). noticable power loss and bogging.

Um, white smoke = coolant. Not a good sign.

If you MAF sensor was not working and it's connected, you'd probably be stalling at idle. At least that was my experience.