AEM UEGO, AMS EMS powered car. Sensor in question was put very close to turbine outlet, maybe 12-15".
Worked “ok” when I bought the car - gauge would read normally, but sometimes freeze at random AFR’s. It would cycle, and then hit 15.8 (for example) and not move until I stopped the car, let it cool a bit, and turn it back on. I thought the sensor was dying so I tested it per AEM’s YouTube how-to (exposing it to no exhaust pegs it lean, placing it in a rag sprayed with brake cleaner pegs it rich) and it tested fine.
I took the downpipe out to try and find an oil leak, and had to unplug the sensor from the harness. I noticed he had a zip tie holding the two ends together, since the clip on the harness end was broken. The zip tie was “crushing” one of the wires. When I reassembled everything, I didn’t include a zip tie. Ever since then, the gauge just reads 14.7/14.8, and never moves. The sensor does not warm up.
I figured the sensor died, so I bought a new one, same part number. Plugged it in, still would not warm up and cycle (out of the car, not running. Should peg lean after a bit.) Tried the old sensor again, nothing. I checked the sensor/harness connected a million times, tried making sure it was pushed in the whole way, etc, nothing. Took the gauge cluster out (wideband gauge is mounted in gauge cluster) to check connection on back of gauge, it seems fine. I cut back a bit of the wire sheath where it was crushed, thinking the connection was severed, but it looks 100%.
So, in my frustration before I posted this, I forgot to check continuity of the wiring. After I posted, I went back out and took the wiring apart. I pulled the 6-pin plug off the back of the gauge, and noticed that pin 1 was “burnt” looking. Pulled the wire/connector out of the plug, and the wiring wasn’t severed. Cleaned it up, stuck the wire back in the plug. Checked the gauge itself for any burning, didn’t find any, so I reassembled everything, plugged the old sensor back in, and wham, worked great.
I think I read in the AEM manual to never turn the power on with the sensor not plugged in. I may have done this (before reading the manual) and that may be why the wire shorted. I’m not sure.
Haven’t driven the car yet to see if the old sensor still freezes or not now that I moved it way downstream, but I’ll find that out today.
well i’m not sure why the AEM isn’t considered a ‘real’ wideband? I have the aem uego gauge and it lined up perfect with the dyno wideband… we tuned my car using the AEM solely… so dunno what the downside or limitation is?
mine never froze… so i don’t have the same issue… but yeah, the sensor needs the heater, so you can’t run the car without heating the sensor and shouldn’t power the gauge / sensor without the sensor plugged in…