MAF calibration/recalibration (LT1)
Thread Starter
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
MAF calibration/recalibration (LT1)
Can the Mass Air Flow sensor loose its calibration or is it hard coded in the MAF's circuitry? Or is the MAF calibration stored/set in the ECM? Can MAF be recalibrated?
[Modified by Lone Ranger, 5:42 PM 1/8/2004]
[Modified by Lone Ranger, 5:42 PM 1/8/2004]
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: MAF calibration/recalibration (Lone Ranger)
The ECM/PCM has a set of tables that are calibrated to the stock un-molested MAF sensor output. If the sensor goes bad and sends eroneous signals to the PCM the PCM will just think thats correct and base its fueling needs on the incoming MAF signal. You can edit the MAF tables within the ECM Prom image or in the case of the later model flash memory PCMs you can reprogram the tables as well. Normally there is no need to do this. Unless you are running a large cam with lots of reversion in the intake track then you may want to "tweak" the tables to get idle stability.
Thats why most aftermarket MAF sensors are junk, you don't know what calibration are in them things and adding one to your car may actually hinder performance because the fuel trims are so skewed because the new sensor is either rich or lean. Stock GM sensor output cannot be changed in any way. I guess GMS (Granatelli Motorsports) is now offering a programmable sensor. But even at that it would take a lot to get that thing dialed in to your cars PCM and get it working even close to what a factory one is.
[Modified by tjwong, 3:48 PM 1/8/2004]
Thats why most aftermarket MAF sensors are junk, you don't know what calibration are in them things and adding one to your car may actually hinder performance because the fuel trims are so skewed because the new sensor is either rich or lean. Stock GM sensor output cannot be changed in any way. I guess GMS (Granatelli Motorsports) is now offering a programmable sensor. But even at that it would take a lot to get that thing dialed in to your cars PCM and get it working even close to what a factory one is.
[Modified by tjwong, 3:48 PM 1/8/2004]
Le Mans Master
Joined: Jul 1999
Posts: 8,683
Likes: 6
From: Phoenix AZ
Re: MAF calibration/recalibration (tjwong)
The ECM/PCM has a set of tables that are calibrated to the stock un-molested MAF sensor output. If the sensor goes bad and sends eroneous signals to the PCM the PCM will just think thats correct and base its fueling needs on the incoming MAF signal. You can edit the MAF tables within the ECM Prom image or in the case of the later model flash memory PCMs you can reprogram the tables as well. Normally there is no need to do this. Unless you are running a large cam with lots of reversion in the intake track then you may want to "tweak" the tables to get idle stability.
Thats why most aftermarket MAF sensors are junk, you don't know what calibration are in them things and adding one to your car may actually hinder performance because the fuel trims are so skewed because the new sensor is either rich or lean. Stock GM sensor output cannot be changed in any way. I guess GMS (Granatelli Motorsports) is now offering a programmable sensor. But even at that it would take a lot to get that thing dialed in to your cars PCM and get it working even close to what a factory one is.
[Modified by tjwong, 3:48 PM 1/8/2004]
Thats why most aftermarket MAF sensors are junk, you don't know what calibration are in them things and adding one to your car may actually hinder performance because the fuel trims are so skewed because the new sensor is either rich or lean. Stock GM sensor output cannot be changed in any way. I guess GMS (Granatelli Motorsports) is now offering a programmable sensor. But even at that it would take a lot to get that thing dialed in to your cars PCM and get it working even close to what a factory one is.
[Modified by tjwong, 3:48 PM 1/8/2004]
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: MAF calibration/recalibration (Zix)
Yes that is correct, modifying the MAF will throw the calibration off. Normally for 99% of all street applications there is no need to modify the stock MAF. Most street engines will never be able to out flow a sensor. Another way to fix your problem is to go into the PCM and recalibrate the MAF tables. Or put it back to stock.
Depending on what year your car is PCM or PROM editing tools are out there to do just that. I had a guy that installed a ZO6 MAF into his 95 F body, let me tell you that was a nightmare tuning that car! But I have done it and it works well. And as for performance gains, well I don't think there was any but the problem was that he no longer owned the stock MAF so I had to make it work, plus he just had to have it.
Depending on what year your car is PCM or PROM editing tools are out there to do just that. I had a guy that installed a ZO6 MAF into his 95 F body, let me tell you that was a nightmare tuning that car! But I have done it and it works well. And as for performance gains, well I don't think there was any but the problem was that he no longer owned the stock MAF so I had to make it work, plus he just had to have it.
Thread Starter
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: MAF calibration/recalibration (tjwong)
Yes that is correct, modifying the MAF will throw the calibration off. Normally for 99% of all street applications there is no need to modify the stock MAF. Most street engines will never be able to out flow a sensor. Another way to fix your problem is to go into the PCM and recalibrate the MAF tables. Or put it back to stock.
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: MAF calibration/recalibration (Lone Ranger)
Yes, anything that disturbs the original calibration of the sensor would throw it off its curve. That includes removing screens and vanes.
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