I have a sc with a 1j-vvti and have the the usual intercooler full exhaust stock turbo running stock boost , car has been running fine and still is but my aem wideband all of a sudden is acting up , it has been reading rich under full load or full throttle 10:1 to 11:5 in fifth gear , but all of a sudden I will be in fifth gear drop down to fourth smash the gas and the gauge will read 10:1 and climb to 11:1 and then the gauge will read" ------" so I don't know what it could be , the gauge and sensor are about 6 month old , I am thinking maybe the sensor but why would it go bad , plus it's way down in the down pipe , not your usual location were people mount it right behind the turbo , any input will be appreciated .

 

Looking at a cross section of the pipe, is it mounted between 10:00 and 2:00 in the pipe? (so condensation drips off the tip)

Also IIRC, they are fairly fragile to rough handling...did it ever get dropped or banged around?

 

It is mounted more like 5 to 6 o"clock it's not at an angle so , I don't know . Just checked my recipt and the gauge and sensor are 3 month old not 6 as I stated before . These sensors can't go bad that quick

 

I called AEM and support said that whether the sensor is mount right after the turbo(which is not good) or way down on the pipe(like its supposed to be) it will read the same.

 

So are you saying that it's basically mounted upside down? IDK if that's enough to cause a failure in only a few months, but it's definitely not recommended. Call AEM and talk to a tech rep there, they are quite helpful.

 

it doesnt matter much the angle its in the downpipe for readings from what i understand, and distance from the turbo has more to do with delay. mounting it the wrong way is mostly going to hurt the exhaust flow if anything.
100% double check for exhaust leaks around the downpipe area, but Its probably fine.

normally when you see the "---" that means your going leaner than 17afr, which is outside of the widebands ability to read accurately. most noticeable when you are at high rpms and you go to neutral (clutch in), you will hit decel fuel cut (on) and the wideband will show "---" cause there is no air or fuel going into the engine at that point, its decelerating rapidly, and then the wideband will return to normal just above where your idle is (thats the decel fuel kicking in, when decel fuel cut is turned off).

I have never gone richer than 10 afr on my car with the wideband in, so I couldn't tell you for sure that it reads "---" when you are richer than 10 afr (the richest it can read accurately), but if I had to guess its alot more likely for a stock TT to go pig rich in boost than leaner than 17afr. your engine would be bye bye if it was really that lean.
hope that info helps.

 

You are correct that the mounting angle doesn't affect the reading; BUT, along with the distance from the turbo, it definitely affects the longevity of the sensor. Per AEM, if you don't clock the sensor so that it drips any moisture downward (off the tip) and far enough away from the turbo to avoid peak heat, you are shortening its usable life...just like any O2 sensor, it is finite.

 

good to know, I have mine mounted very close to the turbo, but its basically pointing towards the ground mounted on top of the dp. i guess that sounds fine for the drip thing.

 

IIRC, AEM instructions were to set it downstream a minimum of 3 feet from the turbo. Their rep said it's not like it will fail outright if you don't (as you well know), but more along the lines that, being a precision, lab grade sensor, it just wouldn't last as long under the harsher conditions.