WB O2 Sensor Life With WI
 

Early this year my PLX M-300TE WB started reading richer AFRs than expected which made me suspicious that the O2 sensor was going bad. It was a few years old but only used for tuning. The last set of tuning was done with WI.

As soon as the new sensor was installed, AFR readings fell into place.
Now I have been retuning since converting from WI to WA. Now with a less than 6 months old O2 sensor and testing with WA, all of a sudden the AFRs have gotten richer again.

My sensor is mounted temporarily in the tailpipe when testing.

Are Bosch LSU 4.2 sensors that affected by high water vapor levels in the exhaust?

Makes me think of getting a 4.9 unit or does it have the same problems?

A little late here, but you may be on to something. Sorry I am no help...
My Innovative has been doing the same thing as soon as my WI was installed. Can't really say for sure while it's injecting, but something strange is happening. When I key to on, it will warm up and max out at 22.4AFR (like normal). When I am driving and let off, it will read maybe 20.8 or 21.2 when off the gas under fuel cut. It never did that before the water injection was installed, always would say 22.4

I guess it's not such a bad thing as the car drives normally and performs as it should.

alcohol is a fuel, so its normal the afr becomes richer.. if it also comes richer when you are sure there is no injection or dripping of the nozzles taken place, then obviously the sensor must have a drift..

All sensors, wideband and narrowband, have drift.

Water injection should have zero effect on O2 sensors, given that vehicle exhaust in a cleanly running engine is a large percent water vapor. (HC + O2 = H2O and CO2)

I don't think the water should have an effect, My innovative unit is still running strong after 3? years i think. Maybe more. Does your sensor have a calibration mode? I know the innovative units such as the one I run has a calibration setting. I have mine installed at the end of the downpipe.

I figured it's strictly coincidental. Computer is programmed to cut fuel on decel above 2000rpm, so it's obviously doing that, but it reads like there is a tiny amount of fuel in there. Either way, it's no big deal. Car runs great, and the water injection works fine :)

Could be the innovative unit. I've read a lot about them and the consensus is they are the most problematic among wideband kits. But then again I have a 26 year old car that's notorious for electric issues ;)

The only problem I had with my Innovative LC1 was two sensors failed.

Once sensor failed after I removed it to install a backpressure test tube. I ziptied it up to the subframe, the ziptie failed and the sensor bounced along the ground, physically damaging it.

$65 later, new sensor in.

That one failed a year later when I had a massive oil-ingestion event (thick blue smoke and detonation at 8000rpm on 18 degrees of timing, naturally aspirated) which fouled the sensor.

I found another source of the Bosch sensor, this time spending $40.

Solved my listed problem back in July.
Previous of the problem, I upgraded my fuel system with an AEROMOTIVE stealth pump with large fuel filter and larger fuel lines. Then I reset my fuel pressure to my base of 40 psi on my electronic fuel pressure gauge that is in the car.

I finally decided to verify my fuel pressure with a very accurate mechanical gauge.
My over 10 year old electronic gauge was reading about 10 psi low!
Going from 40 to 50 psi adds over 11% more fuel flow.

Got a new gauge and reset my fuel pressure. All is fine now.