I'm having problems with my tune.
I set my fuel map cruising to 14.25 so could hopefully still be in o2 sensor range. During cruising my target afr reads 14.4-14.5 and my o2s read .8v
I'd like to auto tune to clean things up but the minimum I can target is 14.4 and .8v seems way too rich for the o2 setting in the advanced setup. So basically I'm asking does anyone know why these numbers seem off? 18 fat bob 114 two brothers and heavy breather

 

 

Thanks.

 

I'm resurrecting this thread as I've run into a similar issue, and wanted to post what is, hopefully a fix.

On the new exhausts that use the 12mm o2 sensors, they cannot protrude far enough into an aftermarket exhaust when using the 18mm bung adapters. So because of this, you can't properly set up auto tune or even get an accurate AFR reading from the o2 sensor. When using a FP3 the sensor data had the AFR off and voltage high (.8 and higher at times). I could not run auto tune properly or get good sensor data readings.

What I ended up doing was cutting the 12mm o2 sensors and replacing them with 18mm bosch universal 4 wire heated sensors. Part 15733. Note if you do this do not solder the wire, use posi-taps or crimps.

The 18mm sensor can now protrude far enough into the exhaust stream to get a reading.

 

So you are using wide band sensors? Or are these 18mm’s you got narrow band just like the stock one?

Interesting you say this, as my S&S pipe uses 18 to 12mm adapters.

Also interesting. Is there a voltage to AFR table we can use to find out target voltage of sensors for a particular reading?

 

the Bosch 18mm i used are narrow band sensors. Here is a table. My bike (2018) has a bias voltage of .450 (which the fp3 see or displays as .50 volts)

14.7/1- 0.50
14.6/1- 0.60
14.5/1- 0.70
14.2/1- 0.80
13.5/1- 0.85
13.2/1- 0.90
13.0/1- 0.92
12.5/1- 0.94
12.0/1- 0.95

 

Very cool. I know what my cruising AFR is set for, per dyno results using a wide band sniffer shoved up the pipe, so I'm interested in seeing how the adapters affect my readings. Thanks!

 

what AFR did you set your cruising at? I know 14.4 is pretty much the go-to.. but been playing with 14.4, 14.2....

 

Whatever is set by my EPA and warranty compliant HD tuner... :-)