I just brought my B2200 out of storage, it has a 13b non turbo engine ran by an e420d Select ECU. I drove it once with no issues, then, I had it idling and I noticed my Afr gauge showing 14.7 at idle, where I am usually at 13. It didn't change at all by reving up, etc... My gauge was an AEM UEGO, connected to serial input on ECM, the ECM was also seeing 14.7. I figured my sensor died since it was 4 years old, so I replaced it. I got the same result, it reads correctly, then after 1-2 minutes, drifts up to 14.7 and stays there. Revving up the engine temporarily made it work once or twice, then it stayed at 14.7. I checked all the wiring, removed it from the vehicle, wiggled it, didn't make a difference. I replaced the entire wideband setup with an Innovative LC-2 with a gauge, connected to the analog 0-5V input and set it up. Everything was working and reading good, then after a couple minutes, it went to full lean 22.4, the ECm saw 5V input, meaning full lean. Anybody else have this happen?

Is it possible the old fuel is contaminating the sensor? The fuel is from last August. I have a Pacesetter FC header on the truck, the O2 is in the collector, not the stock location. I don't see any exhaust leaks.
leaks.
TLDR - AEM wideband didn't register, replaced with Innovative Wideband, also doesn't register.

 

I figured it out. My replacement wideband was defective, in the same way my first one died. Replaced my new wideband with the one that came with my new gauge kit, and it's been working fine. Could have kept my old gauge, but what are the chances.