Are all wide band sensors consumable?

mkiiichip

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Sep 10, 2007
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I was reading through the MoTeC catalog and found this,

MoTeC said:
How long will the Lambda Sensor Last?
A Lambda sensor is designed as a consumable item which means like a spark plug, it wears out with use. Typically you may notice the sensor begin to slow down in its response to changes in lambda when it becomes worn out. This normally occurs in about 500 hours on unleaded type fuels but is reduced to 50 hours for lead. Like Spark Plugs, the sensor can be fouled in a matter of minutes with improper air fuel ratios and the sensor can crack if it is over torqued or dropped. For this reason, there is no warranty on Lambda Sensors.

I know that improper AF ratios, burning oil, excess heat, among other things can cause a shorter life, but i have never heard that they should be considered a wear item.
 

DangoAZ

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Jun 13, 2007
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I never heard that... And if you figure you drive an average of 50 MPH? (mixed highway and city), you need a new one every 25,000 miles based on motec's information. That's not too bad, but it's not exactly confidence inspiring either. If you can't feel confident in the tune of your motor from the WB output... you might feel like you're pulling the pin on the grenade.
 

DangoAZ

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Jun 13, 2007
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GrimJack;1607375 said:
Definitely a wear item. I've never seen a wideband sensor with a long life expectancy. This is one of the big reasons why OEM depends on narrowband sensors.

Could you elaborate? I have no experience with a WB failure. My LC1 only has about 5K miles on it in 2 years. What is your experience with short (miles, time, relative to?) life expectancy?
 

Poodles

I play with fire
Jul 22, 2006
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Most of the widebands run the sensors off of modern cars which are 100K mile wear items. Also, keep in mind placement of the sensor and how good your tune is (much like spark plugs).
 

GrimJack

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I'm reasonably certain that 100k is an educated guess on their part, these should really be rated in hours of use, not distance traveled. My Zeitronix didn't last very long - just over a year, so around 20k km.
 

Jeff Lange

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GrimJack;1607375 said:
Definitely a wear item. I've never seen a wideband sensor with a long life expectancy. This is one of the big reasons why OEM depends on narrowband sensors.

Every Toyota on the road these days has at least 1 wideband and 1 narrowband sensor, most have 2 of each. They definitely do wear out over time, and especially when you are monitoring their output you may notice changes over time. They should last quite some time though.

Most aftermarket wideband setups do use relatively cheap sensors though, so it's not THAT bad to replace them.

Jeff
 

DangoAZ

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Jun 13, 2007
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Poodles;1607413 said:
Also, keep in mind placement of the sensor...

I have a down pipe with a WB bung just behind the narrow band bung. I have heard heat = bad, and I thought of putting one of these in there:

View attachment LC1 bung heat sin&#.bmp
http://www.innovatemotorsports.com/xcart/product.php?productid=16148&cat=250&page=1

But for $90, it's $10 more expensive than a replacement sensor! <-- to Jeff's point

What I'm starting to consider, though, is the failure mode of the sensor itself. If it's not a fast fail (Grim - How did you know your sensor went bad?), then you run the risk of trusting a data set that is faulty and grenading a motor. And how do you know when that'll happen short of comparing Vf from the narrow band to the wide band AFR on a frequent basis? (Jeff - Do you know if modern cars do this kins of sensor test as a self-check?)

I'm not one to run around thinking the sky is going to fall... just thinking.
 

GrimJack

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When mine failed, it went from reading 14.7 at cruise to reading 23+ all the damn time. It wasn't a slow thing, either - fine one day, and toast the next. As I was using it to run the MAFT Pro in open loop all the time, it was *really* obvious when it went. Furthermore, it failed in a way that ran the engine too rich instead of too lean, therefore protecting the engine.

I switched to an Innovate unit instead - it cost about the same as a replacement sensor, and I could get it right away instead of waiting for a replacement sensor from Zeitronics - and it's now lasted at least twice as long. I've heard the AEM units last a very long time as well.
 

Jeff Lange

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Modern cars are always comparing the inputs of the 2 sensors to detect catalyst irregularities and problems with the sensors. You can monitor the O2 sensor output using the plug-in diagnostic tester as well.

Modern ECU's monitor so much stuff and give very specific error codes to specific conditions related to specific parts, it is SOO much more advanced than anything in the Supra.

Jeff
 

grimreaper

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Jul 2, 2008
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AEM WB with 2+ years of DD on pump gas= 0 issues to date. If the ecu is still in control of cruise/idle/part throttle, it should be obvious when the sensor starts to age.
 

Cz.

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Mar 31, 2005
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The sensors are wear items, however just using pump gas, they should last for a while. It's when you start running leaded gas that the sensors end up dying quickly.
The two most common widebands are the Bosch sensor and the NTK sensor. My understanding is that the NTK sensor is much better with leaded gas, but it also costs more. In most cases your simply going to use the one that your WB controller is setup for.
 

Orion ZyGarian

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Apr 2, 2005
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I've read that outside of leaded fuel, excessive heat is one of the quickest ways to kill a sensor. Almost every modded car I see has the wideband right after the turbo, at or near the stock location. The AEM kit I bought says to have the sensor a couple feet down stream from the turbo for a longer life. Guys at the local shop have said they've had no problems with their sensor placement, but regardless, I'll be putting mine closer to the passenger seat.