Very weird issue with widebands on single Coyote

[fulanititoo8198]

SCT

My set up is a single turbo with two 02 sensor bungs in the downpipe. One is for the OEM (passenger side) wideband sensor and the other for my AEM wideband sensor. The oem driver wideband is unplugged/not used and turned off in the tune.

The issue is in livelink at wide open throttle ONLY the STFT stops working and seems to freeze at a value of 1.00. As soon as I let off the sensor immediately begins to oscillate again. The lambda reading works just fine.

I've tried new sensors, changing tunes several times, returning to stock, and checked the wiring several times. I did not use extensions, I simply pulled the wiring from the harness and extended one wire which was too short. I soldered it securely it in place.

The weird part is that the only way that it will work is if I reconnect the second (drivers) wideband sensor back into the downpipe even though it is turned off in the tune.

So right now my only solution is to have another bung welded into place which is a hassle and I really don't want 3 widebands. Looking for any ideas before I have to pull the downpipe to get welded, coated, and rewrapped.

 

[oxfordgt]

Not sure how the coyote pcm works but earlier ones once you go to open loop the STFT shows base fuel commanded lambda. My base fuel map is all 1 lambda and I use the WOT multiplier to adjust so when I go WOT the STFT shows 1.

 

[stang910]

I had this same issue except I was deleting the rear O2's. I know you have can make the changes to use only one wideband, but not sure if it works correctly since I haven't had to do it yet. I'm sure it was already done, but just to make sure did you change the adaptive mapping to read from one bank? Then the next question would be are you using the correct O2 wire that your tune is setup for?

Why not plug both front O2's in and use one of the rear O2 bungs for your aftermarket wideband?

 

[fiveohalex]

FAOSC switch on or off?

 

[ctgreddy]

On newer fords (anything with widebands as primaries) we no longer put one of the shops widebands in because it does some funky stuff. Anytime we take out one of the rear o2's for our shop sensor sometimes they do things similar to yours, sometimes they act fine. If you want it to function like normal again I'd put both primaries and both secondaries back in.

 

[fulanititoo8198]

Thanks for the notes guys, I'll forward it to my tuner to see if it's of any insight. I guess a good question is does anyone actually run a setup similar to mine that works? Single stock wideband sensor in the downpipe with no rear o2s?