what KILLS O2 sensors?



what KILLS O2 sensors?

Postby grumpyvette » April 10th, 2010, 2:40 pm

leaking injectors or any source of a constantly overly rich, fuel/air mix can and will eventually screw up your O2 sensors, try hard to tune your engine to stay in the 12:1-15:1 fuel air ratio range, the closer to 14.7:1 , and the less contaminates like coolant or moisture, the better the sensor likes it, and the longer its likely to last
RUST,AGE,MOISTURE, ACIDS, COOLANT IN THE EXHAUST,ALSO TEND TO LIMIT THE SENSOR LIFE EXPECTANCY
excessive use of injector cleaner, leaded fuels leave clogging residues, or water absorbing fuel additives, added to the fuel or coolant seeping into the exhaust or an excessively rich a/f ratio will eventually kill an O2 sensor

"Water absorbing fuel additives such as alcohols....or use of fuel drying additives, that contain alcohol as most do, tend to damage sensors"

I'm NOT sure if its the alcohol or something ELSE in the cans of products similar to (DRY GAS) and similar additives LIKE injector cleaners but its been depressingly common to see the O2 sensors quit after awhile if that type of products been used frequently, Ive got brother-in-laws and friends that regularly dump that stuff in their tanks and we replaced O2 sensors almost yearly until I got them to just change the oil and all the filters regularly and stop dumping the latest wonder additive in the tank every other fill up
Its not a good idea to add injector cleaner formulas to the fuel on almost every fill up.
but ID also point out that alcohols HYDROSCOPIC (SPELLING??) IT tends to absorb moisture and the combo of excess moisture, heat and exhaust tends to eat sensors, keep in mind a mild sulfuric acid is formed from exhaust gases and moisture.
keep in mind O2 sensors need to run fairly hot and only provide data to the CPU over a limited fuel/air ratio range thats NEAR 14.7:1
most decent headers have 32"-39" long primairy header pipes so the collector is at least that distance from the exhaust port
18" from the exhaust port makes sense with something like shorty headers

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but you would only read the exhaust from a single cylinder on true performance headers at 18" from the exhaust port
thus collectors for performance headers have sensor bungs welded in the collector where they are located in the flow of exhaust from all the cylinders on that bank, but this presents a potential problem, because all oxygen sensors work best at higher temps (the reason 18" from the exhaust port was advised) so its best to select the HEATED OXYGEN SENSORS in that application

single wire sensors should be located close to the exhaust port
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the later multi wire heated sensors are much more tolerant as to actual location and work fine in header collectors
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viewtopic.php?f=80&t=728&p=9217&hilit=oxygen+sensors#p9217

viewtopic.php?f=56&t=961

viewtopic.php?f=44&t=1599&p=3767&hilit=oxygen+sensors#p3767

viewtopic.php?f=55&t=1241&p=2648&hilit=oxygen+sensors#p2648

viewtopic.php?f=32&t=596&p=1200&hilit=oxygen+sensors#p1200

viewtopic.php?f=56&t=495&p=613&hilit=oxygen+sensors#p613

http://www.superchevy.com/how-to/additi ... ult-codes/

viewtopic.php?f=56&t=3049&p=8053&hilit=oxygen+sensors#p8053


read the links as they contain a good deal of info


early L98 typically run 1 oxygen sensor in front the common catalytic converter.

LT1 and LT4 run Four (4) oxygen sensors.

One in front of each catalytic converter.

One behind each catalytic converter.
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http://auto.howstuffworks.com/question257.htm

viewtopic.php?f=50&t=1853&p=4848&hilit=+air+fuel+meter#p4848

viewtopic.php?f=55&t=109

http://www.picoauto.com/applications/lambda-sensor.html

http://mr2.com/TEXT/O2_Sensor.html

http://www.scirocco.org/tech/misc/afgauge/af.html

http://en.wikipedia.org/wiki/Oxygen_sensor

http://www.casperselectronics.com/store ... cts_id=698

http://www.asashop.org/autoinc/june/Tech2tech.htm

http://www.aa1car.com/library/o2sensor.htm

http://www.asashop.org/autoinc/dec2002/mech.htm

http://www.wellsmfgcorp.com/pdf/Counterpoint2_3.pdf

http://www.pelicanparts.com/bmw/techart ... sensor.htm

http://www.engine-light-help.com/oxygen ... codes.html

http://www.youtube.com/watch?v=DQN9MBKvexs

http://www.walkerproducts.com/faqs_o2.html

http://www.aa1car.com/library/wraf.htm

http://auto.howstuffworks.com/framed.ht ... ensor.html

_________http://en.wikipedia.org/wiki/Stoichometric_________

viewtopic.php?f=44&t=773

viewtopic.php?f=50&t=1853&p=4848&hilit=ratio+meter#p4848

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Bosch LSU4.2 WBO2 Sensor
http://www.boschautoparts.com/OxygenSen ... nsors.aspx

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if yours is defective or missing why not just weld on a bung on the header or exhaust pipe and install the correct 02 sensor?

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=3049&hilit=oxygen+sensor

http://www.ecklerscorvette.com/corvette-exhaust-oxygen-sensor-1982-1986.html

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NTK WBO2 Sensor
http://www.ngksparkplugs.com/products/o ... p?mode=nml
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it helps if you understand that oxygen sensors do not measure your true fuel air ratio,entering the engine, but instead measure the remaining oxygen content of the burnt exhaust gases,and there are both narrow and wide band sensors
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You cannot turn OFF the rear 02s, only turn off their error codes from tripping.

Bad idea not using the rears as they also are used by the PCM to compute the fuel trims
racingvette posted this additional info
"As per GM :

The rear oxygen sensor, located after the catalyst, is used for fuel trim corrections on OBD-II vehicles. By virtue of its location, the rear sensor is generally protected from high temperatures and much of the contamination that affects the front oxygen sensors.
In addition, the rear sensor sees exhaust gases that are equilibrated – they have already been converted by the catalyst so that there is very little residual oxygen.
This allows the rear sensor to respond to much smaller changes in exhaust gas oxygen content. In turn, it then possible for the rear sensor voltage to remain near the 0.45 volt switchpoint.

This characteristic allows the rear sensor to be used for fuel control. Under steady rpm and load conditions, the short term fuel trim bias can be adjusted so that the rear sensor voltage is maintained near the 0.45 volt switchpoint.
This ensures that the catalyst is getting a stoichiometric exhaust gas mixture, despite any shift in the front sensor switchpoint.
The rear fuel trim corrections are learned in KAM (Keep Alive Memory).
Internally, this system is known as Fore Aft Oxygen Sensor Control (FAOSC). Note that FAOSC learns and reacts very slowly because the catalyst, with its large/slow oxygen storage and release characteristic, is part of the control loop. Also, this system cannot be used with a "y-pipe" exhaust where a single rear sensor would try to adjust dual front sensors.

Rear O2s if you will are a fine tune of the commanded fuel flow but are very much part of the model used in the PCM's math to correct AFR for closed loop

This means running no rear O2s or Simms will effect how the PCM computes what the fuel trims are.

There is 2 02 wiring connectors per side on frame rail
Each side has 2 different shaped wiring connectors and the front and rear 02s have a matching connector shape so they cannot be connected in wrong UNLESS someone has hacked the 02 wires and used the wrong connector or incorrect wiring order.

Look at the stock 02 sensors and it will be clear which shape they have and match to the main wiring harness.

If you are wrongly using the rear 02 connectors for the fronts then they are on the wrong side of engine as the right rear connector is for the left rear 02 and same for left side is for right rear 02.

Using a OBD-II scanner would quickly tell you the state of the 02 sensors and wacked fuel trims would point to 02s in the wrong placement"
one factor I seldom seen mentioned is the fact that fuel must be atomized and mixed with air in a vapor form to burn effectively, and that oxygen sensors measure the remaining un-used oxygen in the exhaust gases, NOT the REMAINING FUEL CONTENT and the difference is important as your tail pipe could be dripping raw fuel while the oxygen sensor reads a LEAN REMAINING HIGH OXYGEN CONTENT in the exhaust gases, being measured by the oxygen sensor data, if the fuel was poorly atomized and far less that 100% of the fuel flow passing thru the cylinders is being burnt efficiently.
a highly effective exhaust header scavenging the cylinder matched to a cam with significant over lap can quite easily promote that result if the fuel is not being efficiently atomized, especially in a fairly cool combustion chamber.

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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: what KILLS O2 sensors?

Postby SS402 » September 9th, 2010, 12:26 pm

I think a lot of people are unknown to the fact that spraying Carb Cleaner in the throttle body will also destroy the O2 sensor/s, that's why we don't want to use anything but gasoline in the tank if we can help it.
The narrow-band 1,2 and 3-wire O2 sensors are guilty of offering a limited range but the newer 4 and 5-wire units are capable of measuring the Oxygen level over a much wider range. The standard non'heated 1 and 2-wire units are the least desirable, then the 3-wire heated unit is much better as it is more accurate at low engine speeds when the exhaust is cooler but the newer 4 and 5-wire units offer the best of both worlds with a heated element and wide-band capability.
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Re: what KILLS O2 sensors?

Postby grumpyvette » August 13th, 2014, 10:12 am

heres a tip posted elseware if you don,t want to weld in bungs for testing probes or sensors in your header collectors ,in your exhaust pipes or while measuring the fuel/air ratio while tuning
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http://www.innovatemotorsports.com/xcar ... ctid=16141
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http://www.innovatemotorsports.com/xcar ... 274&page=1
http://www.innovatemotorsports.com/xcar ... 274&page=1
bytor wrote:Another option is to use tail pipe clamp adapter (3728) on the end of your exhaust. It uses a venturi effect to sample exhaust gas while keeping air away from the sensor. You probably would not wont this setup for a permanent install but it would keep you from having to drill holes. With your short exhaust, I would not see any significant lag or delay in the readings. I have been to a few dyno shops and the all use something like this to capture AFR during dyno runs.

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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: what KILLS O2 sensors?

Postby bytor » August 13th, 2014, 3:23 pm

Here's some additional tips out of the LM-2 manual on O2 sensor life problems.

* Do NOT install the Bung below the 3 o'clock or 9 o'clock position. Condensation
can form in the exhaust pipe and permanently damage the sensor. 6 o’clock is the
absolute worst position to mount the sensor.

* Wide band oxygen sensors, like the one shipped with the LM-2, are designed to
work with unleaded gasoline. Use with leaded gasoline will significantly reduce the
lifespan of the sensor. The reduction is directly proportional to the metal content of the
fuel and the tune of the engine. In most cases, a wide band sensor will provide
accurate measurements somewhere between 50 hours and 500 hours with leaded fuel.

* WHEN INSTALLED IN THE EXHAUST, THE OXYGEN SENSOR MUST BE
CONNECTED AND OPERATING WITH THE LM-2 WHENEVER THE CAR IS
RUNNING. AN UN-POWERED OXYGEN SENSOR WILL BE DAMAGED WHEN
EXPOSED TO EXHAUST GAS IF NOT PROPERLY POWERED.

* The maximum temperature of the sensor at the bung (the sensor hexagon)
should not exceed 500C or 900F. If these temperatures are exceeded in your
application you should either install a double length bung (one inch) or the Innovate
Motorsports Heat-Sink Bung extender (HBX-1). The double length bung is also recommended for situations where airflow is restricted.

* It is NOT a good idea to do a sensor warm-up prior to starting the vehicle.
Depending on the climate and the sensor position in the exhaust, condensation can
form in the exhaust pipes. This condensation could then be blown by the exhaust
stream against the hot sensor when the car is started. The resulting heat shock can
permanently damage the sensor.
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Re: what KILLS O2 sensors?

Postby philly » February 16th, 2015, 11:37 am

you also need to be aware of what kind of chemicals you use on the threads of bung plugs, the o2 sensor itself, and what you use to clean throttle bodies and mass airflow sensors... if its going to be ingested, and the car has a functioning 02 sensor that im relying on for engine control, i use maf cleaner everywhere...

0905gmhtp_04_z+crc+mass_air_flow_sensor_cleaner.jpg


i dont care if im cleaning throttle bodies, pcv valves, MAFs, other sensors on the manifold that may have gunk in them, i use the MAF cleaner because it does the job and does it safely with respect to both the MAF and the o2 sensor, i never spray carb cleaner, starter fluid, brake cleaner, etc into the motor because what goes in must come out and that stuff could potentially damage sensors in both the intake manifold and o2 sensors on the exhaust side.
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