help with suspected failure of haltech wb1

So story goes im building a engine dyno and i was just testing the absorber/water brake now that i have finnished maching it

I just had a k series mounted up to it and was doin the initial testing makings sure everything was running smoothly balenced ect

First pull with decent rpm just controlling the water valve manually at this point just creapin up on everything.

i get to 7500 ish rpm and my lambda reading on the haltech just goes to open circuit so abort the run power cycle the ecu a few times and then its reads lambda 22.02 so i leave it for a few hours had things to do when u come back i update firmware on everything and it goes back to reading open circuit when the engine is running .

So im thinking now probably the lsu4.9 is dead its ok i have a spair so i just plug it in without installing it fire up the engine it heats up ect and reads free air so im thinking cool throw it in the headers ready to go fire it up get open circuit as soon as it finishes heating so i scrach my head for a bit then i pull it back out fire up the engine with the sensor out of the exhaust reads free air as soon as i poke it in the hole it goes to open circuit so i go back to the original sensor same thing .

So finaly i fire the engine up with the sensor out of the exhaust and grab my lighter n pump gas in the end of the sensor and as soon as i do it goes from free air to open circuit grab the other sensor same thing so im leaning towards the wb1 can widband controller has taken a dump any other ideas its not new it was in a car for 18 months with no issue