***MAT Sensor and ECM ????? ***

[Granny 2]

Do the readings from the MAT sensor (near the air filter) have the ECM make any adjustments? Is that information used for anything?

 

[mgmshar]

The readings from the MAT sensor are used by the ECM to correct the MAF readings (for a stock MAF). At very high or low temperatures (say 120 degrees or 0 degrees), these corrections are significant. I don't remember exactly how much, but I seem to recall they were over 10%.

There is also a table that adjusts spark timing vs. MAT in the stock chip code. However, it is zero'd out in the stock calibration, if I remember correctly. I believe that most aftermarket chip makers leave it zero'd.

 

[1badTTA]

On the stock chip it was used to calculate the density of the air going through the MAF sensor. I heard that alot of the chips out now have that table zeroed out and it isn't used, but I don't know too much about it. Guess it would just depend on what chip you have. I also heard it was possible to hook up a 3bar MAP sensor to it for reading boost in Direct Scan, but I can neither comfirm nor deny those allegations.

 

[bruce]

Originally posted by 1badTTA
On the stock chip it was used to calculate the density of the air going through the MAF sensor. I heard that alot of the chips out now have that table zeroed out and it isn't used, but I don't know too much about it. Guess it would just depend on what chip you have. I also heard it was possible to hook up a 3bar MAP sensor to it for reading boost in Direct Scan, but I can neither comfirm nor deny those allegations.

If your using a Translator, then the later MAF does it's own IAT.MAT correction so you can 0 out the fuel correction.

Yes you can log a 3 Bar using one of Ken's Boost sensing harnesses.

You can even get clever and make boost referenced changes for timing and fuel. But, it's alot of work.

You also have to work out the temp to boost corrections for it to make sense, in what you record.