LTFT's Banks different

[heavyfoot]

Im getting ready to tune SDVE. Im noticing bank 1 is typically abour 4% leaner than bank 2. Both float between -5% and +5%. I can find no noticible leaks in either exhaust system. I can not see any track of black at the joints nor can I feel any leaks. I have SLP long tube headers. So O2 sensors are farther away than stock positions but are basically the same distance from teh heads for each bank. Whats and acceptable difference in LTFTs between banks?

[TAQuickness]

Acceptable would be within 2% of each other. If you have one bank reading -5 and the other reading +5 you have a problem somewhere that needs fixing

[heavyfoot]

Its not quite that far off. Bank 1 is avg around +4% leaner than bank2.

[TAQuickness]

I would start looking for leaks and or lazy o2's. Try swaping the BxS1's from side to side to see if the problem follows the O2's

[heavyfoot]

great idea. I also have the 2 sensors (which I believe are the same) that I removed when I stripped out the cats.

[vettenuts]

When are they far apart, I found that the EVAP would push them apart as the percentage climbed.

[heavyfoot]

I created a calc pid to look at the difference between the banks. Will log tomorrow.

[heavyfoot]

After having created calc pids for delta LTFT between bank 1 and 2. I'm seeing some cells bank 1 is about 4% leaner than bank 2. In other cells the are exact or only differ by 1 or 2%. Interesting part is the cells generally used for driving the banks differ by about 4%.

[heavyfoot]

Being that the total differece between banks never exceeds ~4% I'll assume all is well since I can't find any exhaust leaks and the sensors appear to be working correctly.

Knowing that I need to get my LTFT's slighly negative...how do I do that?

[TAQuickness]

need to let the PCM know how much air is coming in + a little bit.