Help, MAF Issue?
Help, MAF Issue? This is my sons stock 2000 SS Camaro.
I normaly tune my 2002 GT-88 Turbo 408, and several friends forced induction cars.
Needless to say all of my tunning is with 2 Bar or 3 Bar Enhanced and with no MAF.
My son picked up this car and it needed some TLC. It ran a little ruff and used more fuel then it should. I threw my scanner on it to see what I could find.
I noticed the LTFT's and the STFT's go way way positive! I then replaced all plugs, wires, and fixed exhaust leak issues. Now the car is running better.
It still was sending the LTF's and the STFT's way positive as you can see on the log. I also noticed when first stated the engine manifold pressure runs around 45kpa, and once it goes into Closed Loop and the fueling is finally corrected the manifold pressure drops to 35kpa or better.
It is obviouse to me the car is running very lean until the CL operation richens it back up.
I disconected the MAF sensor and made the MAF fault at 0. I reset the fuel trims and fired the car up. With the MAF deleted the engine manifold pressure at startup is very close to 35kpa. Once it goes into closed loop the LTF's stay close to 0, (4 max). The O2's start switching almost as soon as it goes into closed loop. Everything looks great.
I then purchased a new stock sensor and put it on the car, flashed the stock tune back in and then made this log.
As you can see even with the new MAF sensor it is still starting very lean, and the LTFT's and the STFT's have to go very positive to richen the car back up.
What the heck is the issue here? Why is the MAF making the fueling so lean? The entire car is stock. I can not imagine I would need to work on the MAF mapping.
Is this normal for a MAF sensor and if so why? What am I missing here?
Any input would be great. Thanks
I used the stock Default Imperial cfg to make this log.
I normaly tune my 2002 GT-88 Turbo 408, and several friends forced induction cars.
Needless to say all of my tunning is with 2 Bar or 3 Bar Enhanced and with no MAF.
My son picked up this car and it needed some TLC. It ran a little ruff and used more fuel then it should. I threw my scanner on it to see what I could find.
I noticed the LTFT's and the STFT's go way way positive! I then replaced all plugs, wires, and fixed exhaust leak issues. Now the car is running better.
It still was sending the LTF's and the STFT's way positive as you can see on the log. I also noticed when first stated the engine manifold pressure runs around 45kpa, and once it goes into Closed Loop and the fueling is finally corrected the manifold pressure drops to 35kpa or better.
It is obviouse to me the car is running very lean until the CL operation richens it back up.
I disconected the MAF sensor and made the MAF fault at 0. I reset the fuel trims and fired the car up. With the MAF deleted the engine manifold pressure at startup is very close to 35kpa. Once it goes into closed loop the LTF's stay close to 0, (4 max). The O2's start switching almost as soon as it goes into closed loop. Everything looks great.
I then purchased a new stock sensor and put it on the car, flashed the stock tune back in and then made this log.
As you can see even with the new MAF sensor it is still starting very lean, and the LTFT's and the STFT's have to go very positive to richen the car back up.
What the heck is the issue here? Why is the MAF making the fueling so lean? The entire car is stock. I can not imagine I would need to work on the MAF mapping.
Is this normal for a MAF sensor and if so why? What am I missing here?
Any input would be great. Thanks
I used the stock Default Imperial cfg to make this log.
Anytime I run across one like this and have convinced myself it's not air leaks or bad injectors or what ever I remap the MAF with a wideband. This is after doing the VE table first. Usually it only takes changing in the idle area.
does the car have an aftermarket air lid on it? Is anything blocking the flow, like a restricted hose in between your throttle body and the lid?
Did you remove the screen from the new mass air meter?
If it is wrong, you can make the computer show you how to setup for the maf sensor.
Log your strims after you shut off long term fuel trims and use the strims to show you what they are at every frequency hz on the meter, then just adjust it by the percentage of error. Then go on another test drive. Make sure though that the values on the maf table keep rising as you go from hz to hz. If there is a lower value in a cell in between to higher ones, it will cause issues, so just manually move them so they climb.
Did you remove the screen from the new mass air meter?
If it is wrong, you can make the computer show you how to setup for the maf sensor.
Log your strims after you shut off long term fuel trims and use the strims to show you what they are at every frequency hz on the meter, then just adjust it by the percentage of error. Then go on another test drive. Make sure though that the values on the maf table keep rising as you go from hz to hz. If there is a lower value in a cell in between to higher ones, it will cause issues, so just manually move them so they climb.