A/F Correction

[welaish]

Recently the car is experiencing huge positive fuel correction. Google, Forums, friends and Tuner. said its a Vacuum Leak.


But nobody answered my question below and I couldn't find any answer, although I saw a similar thread in Romraider iwsti and NASIOC Forums without solution


Why the Positive correction is only on ~3.0K RPM? and on all gears.


below is 3 logs:
1. 2.5K RPM Correction is Negative or Normal
2. 4.0K RPM Correction is Negative or Normal
3. 3.0K RPM Correction is Positive.


The AFR on the Wideband is perfect 14.7 and the car is running perfectly no difference.

https://drive.google.com/file/d/0B6zn_kRV08vAMk1hYlAzWjBHWWM/view?usp=sharing
https://drive.google.com/file/d/0B6zn_kRV08vAQ1BkSDZ1Q0tEeXc/view?usp=sharing
https://drive.google.com/file/d/0B6zn_kRV08vAcjdVQ1dZVE42WFE/view?usp=sharing

 

[Alin]

[MENTION=4577]TK-421[/MENTION] @HolyCrapItsFast

 

[welaish]

Thanks [MENTION=1172]Alin[/MENTION] I would like to add that:

1. I cleaned the MAF sensor
2. Tried another MAF sensor
3. Checked for Exhaust leak
4. Did Leak test using carb Cleaner
5. Did another leak test by pressurizing the intake and adding soap
6. cleaned Injector

Grounding can cause a similar issue? if yes how to confirm?

check the below pics as well I appreciate your help


https://drive.google.com/file/d/0B6zn_kRV08vARnl5d3EyMWpmXzA/view?usp=sharing
https://drive.google.com/file/d/0B6zn_kRV08vAOXBkdUcwY3pZYkk/view?usp=sharing
https://drive.google.com/file/d/0B6zn_kRV08vAanZ1bHMxbmRWU2M/view?usp=sharing

 

[Spamby]

Sounds like the 3k RPM stumble that's prevalent on the 08+ cars.
I believe it to be caused by tune and factory fuel system setup, the fuel pressure regulator and dampers. The system runs lean for a bit in that range, the ECU compensates by dumping fuel.
Some guys fix it with tuning or adding a fuel line extension of around two feet or a combination of both. Others remove the factory fuel regulator and damper and go with an aftermarket regulator and fuel lines. Still yet, others retrofit a GD regulator setup.

 

[welaish]

Sounds like the 3k RPM stumble that's prevalent on the 08+ cars.
I believe it to be caused by tune and factory fuel system setup, the fuel pressure regulator and dampers. The system runs lean for a bit in that range, the ECU compensates by dumping fuel.
Some guys fix it with tuning or adding a fuel line extension of around two feet or a combination of both. Others remove the factory fuel regulator and damper and go with an aftermarket regulator and fuel lines. Still yet, others retrofit a GD regulator setup.

Thanks [MENTION=1507]Spamby[/MENTION] I still suspecting that, but the car was running fine do you think it can appear without any new mods?

 

[m8ttixsti]

Cobb also sell a kit that eliminates the problem. Check it out. I will be getting soon once I get my injectors headers and up pipe. My 2013 was doing it when it was stock. The tuner got it a little better but told me to up grade to the kit that Cobb has.

 

[Spamby]

Thanks [MENTION=1507]Spamby[/MENTION] I still suspecting that, but the car was running fine do you think it can appear without any new mods?

It's always there, from what I gather. Sometimes mods or atmospheric conditions can make it more prevalent, from my understanding.
It was described to me as a "water hammer" effect by [MENTION=171]Td_d[/MENTION]. Romraider had some good info on it.
This is just an idea though, You may want to recheck everything. Also, the other dudes mentioned will definitely have their .02 so let's see what they say.

 

[Boogieman98]

I added the two feet of line and AWDTUNING couldn't tune it out but I think Holycrapitsfast has success with tuning it out.

 

[HolyCrapItsFast]

The logs indicate a possible massive leak. The learned column is extremely positive throughout the entire run on all three logs. I understand that total fuel trims are reasonable when you consider both A/F Correction and A/F Learned but the learned column indicates a trend over time and this may just be indicating an intermittent leak.

May I recommend you reset the ECU, Idle for 5 minutes, drive it for 10 minutes and then take another log. Please take just one log of normal driving and for at least 30 minutes of driving.

Please log only the following data to allow more data to be recorded.

A/F Correction #1 (%)
A/F Learning #1 (%)
A/F Sensor #1 (AFR)
CL/OL Fueling
Engine Load (4-Byte)
Manifold Relative Pressure (Corrected)
Target Boost (4-byte)
Mass Airflow Sensor Voltage (V)
Throttle Opening Angle (%)
RPM

 

[welaish]

[MENTION=9]HolyCrapItsFast[/MENTION] will do that. Thanks for your help.

 

[TK-421]

You can also email your logs to me to look at as well CBTuned@outlook.com

 

[TK-421]

This will also explain some things in better context for you

http://youtu.be/4qsVA8gCBJ4?list=UUOxb44Fs0BFuVlu2ik7nSBw

 

[welaish]

thanks [MENTION=4577]TK-421[/MENTION] for the video. will send you log in mins.

 

[TK-421]

thanks @TK-421 for the video. will send you log in mins.

Your welcome

 

[TK-421]

[MENTION=4684]welaish[/MENTION] I just received your logs, I will review them, do you happen to have the ROM file handy?

 

[welaish]

Yes I do have that would you like to recieve it?

 

[TK-421]

Yes I do have that would you like to recieve it?

Yes please send it

 

[welaish]

Sent.

 

[HolyCrapItsFast]

It would be nice to post the log so we all can see.

 

[welaish]

[MENTION=9]HolyCrapItsFast[/MENTION] i agree. Will post it now.