Is O2 sensor needed with Alpha N

Martin I currently use V2.20 on my AN (which is an even older version that your AN). It also has just the 3 pin X3 plug.  Strange that the software crashes, perhaps you send a more specific bug report?

Ask your tuner to provide the binary file. Then you can take a look at it, and also see what is different over stock.

you cant run any sort of wide band lambda control -- only narrow band control.  You can hook up the stock sensor to the engine harness (IOW you run both WB and NB sensors at the same time)  or you can use the NBsimulated signal from your WBO setup and feed that to your engine harness (using a special connector).  In either case, you have 2 options:

-- blue + black closed == motronic O2 is switched off. you can switch on AN O2 control  (via the AN control software)

-- black or blue open (but not both) == motronic O2 switched on. in this case DO NOT turn on the AN O2 control.

if you run motronic O2 control it is active for loads up to 80% and rpms up to ca. 4800 rpm.

if you run AN O2 control, the cutoff rpm is ca. 5000 rpm and the load cutoff is programmable "controller poti limit" on the "oxygen control page" in the AN control software.  To edit use the tab key to navigate to the text box and the cursor keys to move the value up or down.  The value is a number between 0-255, the value in percent is your entered number divided by 255. e.g. to cutoff O2 control at 70% load enter a value of 178 in the text box.

With a WBO derived NBsim -- the response is very quick. You can suddenly increase throttle from 20% to 70% and hold that throttle opening,  the O2 controller will quickly bring the lambda value back to 1.0 (14.7 AFR).

conditions where the controller might not bring the O2 value back are when the "integration limits"  (default == +/- 40) are exceeded. If e.g. at the load site of 70% throttle the map value is far from the necessary value to produce lambda=1, the O2 controller will try to currect this up to +/-40 units. Once this limit is reached, the O2 controller will switch itself off and your mapped value is considered "out of bounds".

The closer your open loop map (== all O2 controls switched off) is correctly tuned, the less the O2 controller has to correct, the less likely that any controller limits are reached.  My open loop map is very good (== the correct lambda value under particular load and rpm conditions) because I drove that way for about 1.5 years fine tuned it.  Now I run the AN O2 controller fed via the NBsim signal.

John