Wide Band and Tail Pipe Sniffer

[Superlite]

I own an AEM X series Wide Band AFR system and plan to use as a portable capability for tuning. I acknowledge permanently mounted at least 18 inches from the head is optimum. The length of my entire exhaust system to include straight thru muffler is 46 inches (117cm) (mid-engine car).

Question1 : When using a tail pipe sniffer with the WB sensor, how much error is actually induced?

Question 2. Will it improve idle low REPM readings to attach an extension on the tail pipe mounting probe and go deeper into exhaust to minimize/prevent any O2 reversal contamination?

Question 3. During tuning if we shut down LTFT and STFT during MAF calibration, do the OEM narrow band sensors work? If not operating, could one be removed, and wide body inserted for MAF/VE tuning only?

[hjtrbo]

Question1 : When using a tail pipe sniffer with the WB sensor, how much error is actually induced?

Joe Simpson on you tube ran this exact test. On average 0.5 point leaner with the tail pipe sniffer

Question 2. Will it improve idle low REPM readings to attach an extension on the tail pipe mounting probe and go deeper into exhaust to minimize/prevent any O2 reversal contamination?

Logic is sound.

Question 3. During tuning if we shut down LTFT and STFT during MAF calibration, do the OEM narrow band sensors work? If not operating, could one be removed, and wide body inserted for MAF/VE tuning only?

The narrow bands are still needed. If the rears are removed there has been many reports here of issues with pegging rich. Best thing to do is weld in a new bung on the bank that the fuel trims report running the leanest. You can buy allen key plugs that are screwed into the bung when the wide band is removed.

[Jarrod.v]

The narrow bands are still needed. If the rears are removed there has been many reports here of issues with pegging rich. Best thing to do is weld in a new bung on the bank that the fuel trims report running the leanest. You can buy allen key plugs that are screwed into the bung when the wide band is removed.

If you force PCM into Open Loop, are the narrow bands still being used to make calculations? I am asking because I did remove the B1S1 narrowband to temporarily install the wideband to make adjustments. Waiting on new headers to arrive to have the bung welded into place for a more permanent solution.

[Superlite]

If you force PCM into Open Loop, are the narrow bands still being used to make calculations? I am asking because I did remove the B1S1 narrowband to temporarily install the wideband to make adjustments. Waiting on new headers to arrive to have the bung welded into place for a more permanent solution.

I'm actually working on a technique from a well established tuning school which shuts both LTFT and STFT off to calibrate the MAF sensor. The method also suggests temporarily setting any AFR multipliers to 1.0 to limit any interference with AFR adjustments. The primary scanner field to collect is EQ Err MAF to make MAF calibration adjustments. The data collection is solely reliant on the WB sensor, hence my question about tailpipe location for data collection.

[hjtrbo]

I'm actually working on a technique from a well established tuning school which shuts both LTFT and STFT off to calibrate the MAF sensor. The method also suggests temporarily setting any AFR multipliers to 1.0 to limit any interference with AFR adjustments. The primary scanner field to collect is EQ Err MAF to make MAF calibration adjustments. The data collection is solely reliant on the WB sensor, hence my question about tailpipe location for data collection.

Tail pipe will be fine. As a test, install the sniffer and set cruise control to 100 - 120km/h on a flat piece of road and drive for a couple of km. Your fuel trims should be nice and consistent and the wideband should be cycling around 1 lambda. If yes, then you're good to go.

If you force PCM into Open Loop, are the narrow bands still being used to make calculations? I am asking because I did remove the B1S1 narrowband to temporarily install the wideband to make adjustments. Waiting on new headers to arrive to have the bung welded into place for a more permanent solution.

Not used to make fuel calcs, but the ECM likes to see them there. I suppose if you shut off the all the codes you might get away with it... Rather just install a new bung for wideband and leave permanently hooked up.