My Q is running just fine, but I am interested in knowing what the symptoms are of O2 sensor failure so that I can add that knowledge to my failing brain cells. I recently had 2 KSs changed along with 1 failing injector and my Q flies.
I have no idea roughly how long O2 sensors last and how their failure might manifest itself, so I am interesed in knowing.
ThanksKen K
Symptoms of O2 sensor failure in a G50 (92 Q with 120K miles)
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goody90q45
- Posts: 3679
- Joined: Wed Aug 17, 2005 2:07 pm
- Car: 1992 Infiniti Q45 (sold)
- Location: Orangevale, CA
Re: Symptoms of O2 sensor failure in a G50 (kdkrone)
Ken- Without plugging in a consult cable, which I understand you will have soon, the only real way to tell is reduced gas mileage. With all the work you've done on your Q, if you're not getting 15mpg around town and 23mpg on the highway it's time for new ones. I just replaced mine, based on the consult reading, and my mileage went from 13.5 to 15.3. I drive about 95% surface streets with a lead foot. With that kind of mileage increase they will pay for themselves in just a few months.
With the (Blazt) consult cable and NissanDataScan on your laptop, good O2 sensors will be oscillating wildly on their readout between 0% and 100%. You'll barely be able to follow the needle on the dial. Bad sensors (mine before they were replaced) will oscillate much slower and stay more in the 20% to 80% range. You'll be able to see the needle move back and forth because the sensors aren't reacting quick enough thus burning more fuel. Wait until you get your Blazt cable up and running before you have new sensors put in so you can compare the before and after readouts.
Another way to determine you have bad O2 sensors (in CA) is to take your DMV renewal notice to a smog station and fail the inspection after which your Q is labeled a "gross polluter" and you can only go to the Test Only stations. I've done this in the past with a couple of other vehicles. Good luck.
With the (Blazt) consult cable and NissanDataScan on your laptop, good O2 sensors will be oscillating wildly on their readout between 0% and 100%. You'll barely be able to follow the needle on the dial. Bad sensors (mine before they were replaced) will oscillate much slower and stay more in the 20% to 80% range. You'll be able to see the needle move back and forth because the sensors aren't reacting quick enough thus burning more fuel. Wait until you get your Blazt cable up and running before you have new sensors put in so you can compare the before and after readouts.
Another way to determine you have bad O2 sensors (in CA) is to take your DMV renewal notice to a smog station and fail the inspection after which your Q is labeled a "gross polluter" and you can only go to the Test Only stations. I've done this in the past with a couple of other vehicles. Good luck.
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: Symptoms of O2 sensor failure in a G50 (goody94q45)
The maximum the O2 can trim the nominal [preprogrammed] injection time is +- 20%.................most are never totally dead [no switch voltage other than the bias of 0.45-0.55 volts] so we usually expect a 10% improvement in steady state highway mpg to 22-23.
Simple to see how close engine is to brand new by observing the adaptive [block] learn which should be close to 98-102 at cruise.
Simple to see how close engine is to brand new by observing the adaptive [block] learn which should be close to 98-102 at cruise.
Re: Symptoms of O2 sensor failure in a G50 (Q45tech)
What do I need to observe the "adaptive [block] learn"? How do I do that?Q45tech wrote:The maximum the O2 can trim the nominal [preprogrammed] injection time is +- 20%.................most are never totally dead [no switch voltage other than the bias of 0.45-0.55 volts] so we usually expect a 10% improvement in steady state highway mpg to 22-23.
Simple to see how close engine is to brand new by observing the adaptive [block] learn which should be close to 98-102 at cruise.
Re: Symptoms of O2 sensor failure in a G50 (goody94q45)
OK, Mike.
I have things working and took a trip around the neighborhood up to about 4-50 mph unsustained. O2 Sensor varied from 0-88, but after I stopped monitoring and was pulling into the driveway, it varied up to 94. There is also an )2 sensor RH which varied the similarly.
Looks like they are pretty good, based on your stats, although they never hit 100.
Ken
I have things working and took a trip around the neighborhood up to about 4-50 mph unsustained. O2 Sensor varied from 0-88, but after I stopped monitoring and was pulling into the driveway, it varied up to 94. There is also an )2 sensor RH which varied the similarly.
Looks like they are pretty good, based on your stats, although they never hit 100.
Ken
Re: Symptoms of O2 sensor failure in a G50 (kdkrone)
I was getting a code (53 maybe) and when checking with consult most of the time the looked ok like the screen shot. But every once in a while one of the sensors would 'flat line' and then I would get a code. My mileage seems quite a bit better with my 2 new 02 sensors.