'7060 to '7427 conversion - remaining fuel trim issues

[dave w]

Interesting Pictures Below.

Same data logs BLM vs. AFR

Approximately 170,000 data points!

dave w

BLM - Near Idle.jpg

BLM - Off Idle.jpg

Near Idle.jpg

Off Idle.jpg

PE Active.jpg

[Daveo91]

Interesting Pictures Below.

Same data logs BLM vs. AFR

Approximately 170,000 data points!

dave w

BLM - Near Idle.jpg

BLM - Off Idle.jpg

Near Idle.jpg

Off Idle.jpg

PE Active.jpg

Thanks for the comparisons, Dave. I think what I'm supposed to be seeing is the wider range of info the WB data logs are providing? I guess what I'm still not understanding is if we adjust the VE tables based on that info, will the NB closed loop system just wash them out and do what it thinks is correct? Another thing I'm not understanding is: how do we make adjustments to the areas that we DON'T want AFR to be 14.7, like decel, highway cruise, and PE? Aren't the adjustments we're making skewing everything towards 14.7?

[dave w]

Thanks for the comparisons, Dave. I think what I'm supposed to be seeing is the wider range of info the WB data logs are providing? I guess what I'm still not understanding is if we adjust the VE tables based on that info, will the NB closed loop system just wash them out and do what it thinks is correct? Another thing I'm not understanding is: how do we make adjustments to the areas that we DON'T want AFR to be 14.7, like decel, highway cruise, and PE? Aren't the adjustments we're making skewing everything towards 14.7?

I look at AFR's and BLM's as measurements. I consider AFR's more accurate then BLM's. Adjusting closed loop with AFR's is " same / same" as adjusting closed loop with BLM's. AFR's and BLM's are measurements. When closed loop AFR's are lean, add fuel to the VE Table When closed loop BLM's are lean, add fuel to the VE Table.

Course Tune / Fine Tune. Course tune is basically correcting the VE Tables. The computer bases the areas that we DON'T want AFR to be 14.7, like decel, highway cruise, and PE on an accurate Course Tuned VE Table. Fine Tune adjusts the areas that we DON'T want AFR to be 14.7, like decel, highway cruise, and PE.

dave w

[Daveo91]

I look at AFR's and BLM's as measurements. I consider AFR's more accurate then BLM's. Adjusting closed loop with AFR's is " same / same" as adjusting closed loop with BLM's. AFR's and BLM's are measurements. When closed loop AFR's are lean, add fuel to the VE Table When closed loop BLM's are lean, add fuel to the VE Table.

Course Tune / Fine Tune. Course tune is basically correcting the VE Tables. The computer bases the areas that we DON'T want AFR to be 14.7, like decel, highway cruise, and PE on an accurate Course Tuned VE Table. Fine Tune adjusts the areas that we DON'T want AFR to be 14.7, like decel, highway cruise, and PE.

dave w

Thanks Dave. Starting to make sense. But what happens when the NBO2/BLM doesn't agree with what the WBO2 is saying? I'll explain with an example. I took my last data log and copied the BLM (off idle) and WBO2 output tables from TP into a spreadsheet. I then normalized both: BLM I divided by 128, WBO2 I divided by 14.7. Then I combined those ratio values into a single table so I could easily see where they differ. In the attached, the first number is the BLM ratio, second number is WB. It actually looks better than I thought it was going to, but there are still a number of cells where one is slightly lean and the other slightly rich. If I tune based on one of the values, won't it make the other one worse? BLM vs WBO2.jpg

[dave w]

Thanks Dave. Starting to make sense. But what happens when the NBO2/BLM doesn't agree with what the WBO2 is saying? I'll explain with an example. I took my last data log and copied the BLM (off idle) and WBO2 output tables from TP into a spreadsheet. I then normalized both: BLM I divided by 128, WBO2 I divided by 14.7. Then I combined those ratio values into a single table so I could easily see where they differ. In the attached, the first number is the BLM ratio, second number is WB. It actually looks better than I thought it was going to, but there are still a number of cells where one is slightly lean and the other slightly rich. If I tune based on one of the values, won't it make the other one worse? BLM vs WBO2.jpg

I have also noticed the differences between BLM vs. WBO2. I consider WBO2 to more accurate. I tune with either BLM or WBO2.

I recently helped with a California Emission tune. BLM failed, WBO2 passed.

Data Below is California Emissions Pass. BLM's are very lean with AFR's looking good.

BLM - Near Idle.jpg

BLM - Off Idle.jpg

Near Idle.jpg

Off Idle.jpg

PE Active.jpg

[brian617]

Not sure what brand o2 you're using, but I like Denso or NTK heated o2s.

[dave w]

For WBO2 I like the AEM 30-4110 https://www.aemelectronics.com/produ...uego-afr-gauge

The AEM 30-4110 is plug-n-play with 16197427 WBO2 Hack.

dave w