I put a Denso from RockAuto on the Montana.
What's the deal on O2 sensors?
- Thread starter pbm
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Like I have said in other threads... BOSCH is latin for BOTCHED!
God I hate there stuff. (oil filters excluded)
God I hate there stuff. (oil filters excluded)
I am even questioning their oil filters now. Remember, in the past, they were made by Champ. Now, they are part owner of Purolator and making them themselves. Forget past history, both Bosch and Purolator. The new L10193's have a lot less media in them than the old ones. Do I trust Botch to be using a higher quality media now to make up for less?
Originally Posted By: StevieC
I would add is that if the computer stores a Catalytic converter problem code, you might want to check the downstream 02 sensor before replacing the costly catalytic. It's rare that the downstream sensor is the problem but I have seen it enough not to warrant it being a fluke.
Can you explain how downstream sensor can go bad but flag converter efficiency (P0420) code? The P0420 comes on when the downstream starts switching too fast. I can not think of any sensor failure which makes it switch faster.
- Vikas
I would add is that if the computer stores a Catalytic converter problem code, you might want to check the downstream 02 sensor before replacing the costly catalytic. It's rare that the downstream sensor is the problem but I have seen it enough not to warrant it being a fluke.
Can you explain how downstream sensor can go bad but flag converter efficiency (P0420) code? The P0420 comes on when the downstream starts switching too fast. I can not think of any sensor failure which makes it switch faster.
- Vikas
My car is 12 years old and has +90K mi. I verified that the O2 sensors were ok with a scanner but I pretty much knew that already because I monitor gas mileage and it never changed with time.
Originally Posted By: Vikas
Originally Posted By: StevieC
I would add is that if the computer stores a Catalytic converter problem code, you might want to check the downstream 02 sensor before replacing the costly catalytic. It's rare that the downstream sensor is the problem but I have seen it enough not to warrant it being a fluke.
Can you explain how downstream sensor can go bad but flag converter efficiency (P0420) code? The P0420 comes on when the downstream starts switching too fast. I can not think of any sensor failure which makes it switch faster.
- Vikas
I have seen some vehicles store a code (can't remember the #) where it means the Catalytic Converter isn't functioning properly and it turns out to be the 02 sensor after the Cat that is the problem and giving the ECU the wrong information. It happens, and is why I said check to make sure it is functioning before replacing a Cat.
Originally Posted By: StevieC
I would add is that if the computer stores a Catalytic converter problem code, you might want to check the downstream 02 sensor before replacing the costly catalytic. It's rare that the downstream sensor is the problem but I have seen it enough not to warrant it being a fluke.
Can you explain how downstream sensor can go bad but flag converter efficiency (P0420) code? The P0420 comes on when the downstream starts switching too fast. I can not think of any sensor failure which makes it switch faster.
- Vikas
I have seen some vehicles store a code (can't remember the #) where it means the Catalytic Converter isn't functioning properly and it turns out to be the 02 sensor after the Cat that is the problem and giving the ECU the wrong information. It happens, and is why I said check to make sure it is functioning before replacing a Cat.
Let me put it this way. If your car is nearing 10 year mark and still NOT throwing P0420/P0430 on original catalytic converter, you are an exception. The most common code if you google would be P0420. I have printed lot of research material from EPA, Ohio State, Colorado State, Illinois State etc and once again the most common emission failure codes are the above.
The reason is pretty simple. Most ECU start flagging the converter efficiency once it drops below 90% (or something like that). The actual increase in the emission when ECU flags the catalytic converter efficiency code is quite small and nowhere near the FTP limit. In the past, many state had ability to do actual sniffer testing if the car had MIL on. If the MIL was for catalytic converter, most cars would pass the sniffer testing with flying colors. These days, if the MIL is on and/or your I/M readiness is incomplete, you automatically fail the test until you fix the car and retest it. Ironically, the passing requirement on a re-test is lot stringent. For example, for initial I/M on a 2000 and earlier vehicle, most states allow *any* 2 incomplete monitor, however, for a retest, the CAT monitor needs to be completed.
Don't ask me how I know all this :-(
- Vikas
The reason is pretty simple. Most ECU start flagging the converter efficiency once it drops below 90% (or something like that). The actual increase in the emission when ECU flags the catalytic converter efficiency code is quite small and nowhere near the FTP limit. In the past, many state had ability to do actual sniffer testing if the car had MIL on. If the MIL was for catalytic converter, most cars would pass the sniffer testing with flying colors. These days, if the MIL is on and/or your I/M readiness is incomplete, you automatically fail the test until you fix the car and retest it. Ironically, the passing requirement on a re-test is lot stringent. For example, for initial I/M on a 2000 and earlier vehicle, most states allow *any* 2 incomplete monitor, however, for a retest, the CAT monitor needs to be completed.
Don't ask me how I know all this :-(
- Vikas
Vikas,
In Ontario they could care less that your CEL is on, so long as it passes the emissions test. We have seen many vehicles pass blowing almost 0's across HC/CO/NOX with CEL's on and with supposedly bad downstream 02's, upstream 02's, bad EGR's and/or worn catalytic converters. My ford tempo was 11 years old with over 300K KM (187K miles) on it with the original catalytic converter on it and it blew 0's on the reports. Too bad that I hit a deer or would most definitely still be my daily driver.
That really sucks that they won't let you test a vehicle simply because the light is on throwing an emission related code if it still passes.
If the readings are still within limits I could care less if there was a Christmas tree of lights on on the dash. It passes.
To me it matters what comes out the tailpipe and not what lights are on.
Sure it will operate more efficiently with all systems working properly, but unless you are using 1980's fuel economy the factory values and other controls/sensors in place can compensate extremely well in most cases.
Now not to start a war, but most American cars I have seen rely heavily on the 02 sensor for proper fuel management and really can't compensate with factory values and other sensors when they have problems and can be a real PITA.
In Ontario they could care less that your CEL is on, so long as it passes the emissions test. We have seen many vehicles pass blowing almost 0's across HC/CO/NOX with CEL's on and with supposedly bad downstream 02's, upstream 02's, bad EGR's and/or worn catalytic converters. My ford tempo was 11 years old with over 300K KM (187K miles) on it with the original catalytic converter on it and it blew 0's on the reports. Too bad that I hit a deer or would most definitely still be my daily driver.
That really sucks that they won't let you test a vehicle simply because the light is on throwing an emission related code if it still passes.
If the readings are still within limits I could care less if there was a Christmas tree of lights on on the dash. It passes.
To me it matters what comes out the tailpipe and not what lights are on.
Sure it will operate more efficiently with all systems working properly, but unless you are using 1980's fuel economy the factory values and other controls/sensors in place can compensate extremely well in most cases.
Now not to start a war, but most American cars I have seen rely heavily on the 02 sensor for proper fuel management and really can't compensate with factory values and other sensors when they have problems and can be a real PITA.
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I've never seen any car where the O2 sensor affected the idle..other than a Honda.
Also you NEED a functioning O2 sensor to make the three-way catalyst work properly. If it weren't for that, there would be no need for an O2 sensor..and in fact some versions of the Ford EEC-IV don't even use O2 sensors because they went in cars designed for leaded fuel, without cats.
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