AEM 300 tuning drifting and bottles of Tylenol.

[Jquest]

i'm trying to tune my VVE table on my gen 4 ly5 2008 sierra. I've tried X by % half. Small increments in zone by zone only, smoothing , etc...etc..., but I'm starting to get a little frustrated. My issue. I believe, might be with my aem wideband . I recently bought the unit. I welded the bung at the 10 o'clock position right before the Cat. Every time I start the truck it's rich. About -5% on average, in gear. in the cell where it idles ( my reference point). But the idle area I feel it's tuned right where I want it. Let me explain. I start my truck and then I have to go for a warm up drive. I usually have to drive around 25-30 minutes and then I see my values start to change. On my idle in gear I scrap the numbers since I know it's not correct from where I first cranked it and restart the scanner software. By this time....my idle is about .98 lambda ,so I know I"m in the ballpark of where I wanna be. Sometimes I restart the scanner like three times depending how long I'm driving .Each time the values slowly start coming into where I want. The problem(s) I'm having is... no two drives are the same. Even though I do the same route under the same conditions. Acceleration, gear selection. and everything in between.
Do these aem 300 drift that much or should I say.... are they that flaky where you might have to drive for about 30 minutes before you think about logging? I can't start logging from the start because the numbers would be so off.....that I would take like a 3 hr drive for the averages to finally drift. Could there possibly be an issue with my aem sniffer or this is something common , being that its not the most expensive in the market? It's driving me crazy that I continue to massage the numbers , sometimes by the valve of +/-10 in certain areas( a zone ) just to bring it closer and I feel I should get the right readings and I go for a drive and it's like WTF! I also print the numbers before I do the " cal coefficient" to verify the surrounding areas and to see how much they might of changed and after like 40 minutes of driving...I'm off. Tonight I drove after a tweak...I printed out my table and compared it to my previous save file. The area has a lower value, but's it's richer. i'm thinking i didn't let the damn sniffer settle long enough. But then again.....could the sniffer just be FCUKED and it's giving me problems, eventough it's new?

[dr.mike]

Somewhere in my post history, there is the calibration verification procedure for the AEM X-series gauges.

https://forum.hptuners.com/showthrea...l=1#post621017

[Jquest]

I've been hesitant to do that being that the sensor was new and that I read up that the sensor should not be turned on without the truck running , due to the heat cycle it does and how high it goes.
But hey....i guess I'll try that just so I can rule that out. Thank you for the response and suggestion Doc.

[dr.mike]

What you need to avoid is starting the engine, with the sensor warmed up. That is, the sensor element is made of ceramic. And, it "warms up" to about `1400?F ( glowing orange ) !. So, hitting it with a blast of (relatively) cold/wet start-up exhaust is like throwing ice-water on a hot windshield, in the sun, in Arizona. The ceramic cracks. Just like a windshield, the cracks spread. 1st they cause air leaks, which affect the accuracy. Then, they hit the electrical traces, and, cause the sensor to get flaky. Then, they hit something vital, and, the sensor is done.

In this case, it is ok to let the sensor warm up and cool off, at its own rate. Do not blow on it ! And, do not leave it on for extended periods, out in fresh air. Eventually, this erodes the electrodes. But, that takes many hours.

The AEM X-series controllers are VERY stable, over time. If you are seeing significant drift, it is, likely, a damaged sensor; or, an air leak, in the exhaust ( I had one of those. It drove me nuts, for a while ). Or, a wiring issue with the analog outputs. Usually, that is due to poor grounding of the analog- wire.