MAF readings?

Les 51

A pint of Diesel please!
Hi Guys,
Need some help please. I plugged my A4 into VAGCOM today to check out some info I was told by the garage that serviced my car.
It came back with no faults (thank god!), but the MAF readings were changing wildly between 130mg/str to 320 mg/str.
Is this ok ? the Specified readings are supposed to be 170mg/str to 180mg/str.
I assuming the MAF sensor has gone wrong and needs to be replaced, but not being very knowledgable about cars I'm not sure .
Any help gratefully received



Registered User
What you need to to is log actual and specified MAF for a full throttle run in 3rd gear. Then plot a graph of mg/str vs. rpm. The rule of thumb is 0.8*mg=power. If actual and specified are wildly different, and/or max values are low then the MAF sensor is probably gone.

My actual and specified MAF values were 5% out and a change of sensor made a small but appreciable difference.

While you are doing this you might as well log and plot actual and specified MAP (mass inlet pressure).


Registered User
When your MAF is gonna say good bye, you can see that in the Block 032. Both values should be close to 0. Out of spec values, like + or - 15% may indicate faulty MAF.