So at the track this last weekend I damaged an exhaust hanger and I had to drive it home 175 miles with the exhaust hanging out of the bottom of the car. Half way home, one of the bolts at a flange in the exhaust backed out so there was a big exhaust leak right next to the o2 sensor and the AEM UEGO just went to a solid 14.8:1. I assumed this was because the o2 sensor was reading atmospheric air since there was a big gap in the exhaust about 3" from the sensor.

I just got the exhaust fixed today, and the sensor is still reading a flat 14.8:1 - the problem I've got now is there's an autocross tomorrow morning.

First of all, what does this mean, is my o2 sensor dead and do I have to replace it?

Second, my tune is good, so can I run the car even if the o2 sensor bit the bullet or is the megasquirt in some kind of failsafe mode when it isn't getting a proper o2 reading?

Thanks guys
-Ryan

 

if your tune is good and o2 correction doing minimal correction under cruise you should be fine, provided you have a good tune.
I take it you weren't doing closed loop under boost so you probably have that tuned in well.
Also disable closed loop operation

 

Shut off all your closed-loop O2 corrections and go for it.

 

It's technically only a warning light at that point, so you will be loosing that safety part of it. In case anything breaks in your fueling, you won't know. I'd be more comfortable with it at an autox over a track day. Just get it fixed after this one.

 

I'd run it at the track, hard.

 

I did as you advised. Car didn't blow up. 1st in class and TTOD. Thanks guys!

-Ryan