I just had my faulty o2 sensor changed...
06-17-2003, 12:51 PM
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CLK 320 Avantgarde
I just had my faulty o2 sensor changed...
Problem is that I can't tell the difference in the smoothness as it still shakes very little. What exactly does it do?
N
N
06-20-2003, 02:53 AM
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CLK 320 Avantgarde
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Well from the diagnostics report, it mentioned I had 3 cylinders on the right misfiring, hence I had it changed. I had a previous problem where the car nearly stalled two times, and I am not sure if it is because of the misfiring?
06-20-2003, 12:00 PM
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1999 CLK 320
O2 sensor measures exhaust gasses and adjust air fuel mix based on the results. That is the basic function. If you engine is misfiring the O2 sensor will do little to fix that.
Fletch
Fletch
06-20-2003, 08:38 PM
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Barflux,
What kind of car do you have? Fletch is right the o2 sensor reads information i.e. air fuel mixture and exhaust (emissions). It is possible that your mass airflow sensor is not functioning properly. That is a common problem especially when I hear that a car is stalling. The miss fire could also be related to that, but don't quote me this is just speculation.
What kind of car do you have? Fletch is right the o2 sensor reads information i.e. air fuel mixture and exhaust (emissions). It is possible that your mass airflow sensor is not functioning properly. That is a common problem especially when I hear that a car is stalling. The miss fire could also be related to that, but don't quote me this is just speculation.
06-22-2003, 05:56 AM
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CLK 320 Avantgarde
I have CLK320 (MY2001)
It was the right 02 uptake sensor the report from STAR reads:
ECU - ME2-SF1 - Motor Electronics 2
P0130 - G3/4 (right o2 sensor before TWC [KAT])
P0300 - Misfiring Damages TWC
P0301 - Misfiring of cylinder 1 Damages TWC
P0303 - Misfiring of cylinder 3 Damages TWC
P0302 - Misfiring of cylinder 2 Damages TWC
P0135 - o2 sensor heater of componet G3/4 (Right o2 sensor before TWC [KAT])
I was told the o2 sensor was faulty? I am not sure now with this many error messages? Also what is TWC? Just found out it is Three Way Catalytic Converter
Appreciate anyones help
N
ECU - ME2-SF1 - Motor Electronics 2
P0130 - G3/4 (right o2 sensor before TWC [KAT])
P0300 - Misfiring Damages TWC
P0301 - Misfiring of cylinder 1 Damages TWC
P0303 - Misfiring of cylinder 3 Damages TWC
P0302 - Misfiring of cylinder 2 Damages TWC
P0135 - o2 sensor heater of componet G3/4 (Right o2 sensor before TWC [KAT])
I was told the o2 sensor was faulty? I am not sure now with this many error messages? Also what is TWC? Just found out it is Three Way Catalytic Converter
Appreciate anyones help
N
Last edited by barflux; 06-22-2003 at 09:48 AM.
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06-22-2003, 06:34 PM
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I can see why they replaced the o2 sensor but that is only a result of the car missfiring. The problem is to find out why the car is missfiring. Although it is possible that if the o2 sensor is not working properly that it could send error messages to the computer which is what causes the missfire. If the o2 sensor is changed and it solves the missfire problem then of course you'll have your answer. If it does not then you need to find out why the missfire is happening. The missfire is likely a timing issue which would make sense that the computer is seeing an error.Is your car still under warranty? If so then the dealer should solve this problem for you. Hope this info helps good luck.
06-22-2003, 08:47 PM
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1999 CLK 320
So is the car still misfiring?
To my knowledge a faulty O2 sensor can product a lot of problems, but a misfire is not one of them. Cat damage is unlikely because most Bocsh or Siemens ICU's have approx. +/- 15% range built in. They can compensate for up to that amount of variation in the readings from the O2 sensor.
Once that range is exceeded the computer will go into ?fail safe? mode or ?default? mode. This will trigger the engine light and the computer will default to a pre-determined mixture for one atmosphere (usually). Unless you drove the hell out of your car I can not see any reason the cat would be damaged. On most modern cars it will take between 5-35 good cycles from the O2 sensor for the light to turn off again.
I would be looking at the coils, spark plugs, spark plug wires and even the injectors for a misfire. Wiring harness, computer, head gasket and intake or exhaust gaskets next. Check of air leaks after the air is metered (after the MAF). These can all damage your o2 sensor but the o2 sensor can not do the reverse. A bad MAF unit is also suspect, but that usually will affect all cylinders not just a few.
Point is if your misfiring and the O2 sensor was replaced the problem most likely did not originate there, you have a problem up stream that merely damaged the o2 sensor and the diagnostics recorded that but not the original problem.
Hope that helps.
Fletch
To my knowledge a faulty O2 sensor can product a lot of problems, but a misfire is not one of them. Cat damage is unlikely because most Bocsh or Siemens ICU's have approx. +/- 15% range built in. They can compensate for up to that amount of variation in the readings from the O2 sensor.
Once that range is exceeded the computer will go into ?fail safe? mode or ?default? mode. This will trigger the engine light and the computer will default to a pre-determined mixture for one atmosphere (usually). Unless you drove the hell out of your car I can not see any reason the cat would be damaged. On most modern cars it will take between 5-35 good cycles from the O2 sensor for the light to turn off again.
I would be looking at the coils, spark plugs, spark plug wires and even the injectors for a misfire. Wiring harness, computer, head gasket and intake or exhaust gaskets next. Check of air leaks after the air is metered (after the MAF). These can all damage your o2 sensor but the o2 sensor can not do the reverse. A bad MAF unit is also suspect, but that usually will affect all cylinders not just a few.
Point is if your misfiring and the O2 sensor was replaced the problem most likely did not originate there, you have a problem up stream that merely damaged the o2 sensor and the diagnostics recorded that but not the original problem.
Hope that helps.
Fletch
06-23-2003, 03:29 AM
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CLK 320 Avantgarde
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I will be contacting dealer again this week to investigate further. My car has not stalled ever, but felt like it was going too, as the revs dropping past 500 and the car began to shake alot, where Iwould the step on the accelerator pedal in N. This has not happened for a few months now and has only happened twice.
Though occassionaly the car very slightly twitches at traffic lights, but runs smooth while driving and no unusual noises or anything. I was just told it was a faulty sensor last year, and they simply reset it. This time I got the misfiring errors, which don't look good, and the dealer told me to have the sensor changed and that was it. The check engine light has never come on. If it does what is connected to MAF, etc?
To be honest, what does a misfire sound like or do? Would you be able to distinguish a misfire, from the occassional twitch at standstill, or does it happen will driving?
Thanks
N
Though occassionaly the car very slightly twitches at traffic lights, but runs smooth while driving and no unusual noises or anything. I was just told it was a faulty sensor last year, and they simply reset it. This time I got the misfiring errors, which don't look good, and the dealer told me to have the sensor changed and that was it. The check engine light has never come on. If it does what is connected to MAF, etc?
To be honest, what does a misfire sound like or do? Would you be able to distinguish a misfire, from the occassional twitch at standstill, or does it happen will driving?
Thanks
N
06-23-2003, 02:32 PM
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1999 CLK 320
If your only feeling a twitch at idle, that is extremely common. My Mercedes, BMW and truck all have an occasional twitch at idle. I notice it more on the Mercedes because the idle is so low.
I am not sure if Mercedes still uses idle control valves for the later 320 and 430 engines. If they do that is what would control the stability of rpm at idle.
I am not sure if Mercedes still uses idle control valves for the later 320 and 430 engines. If they do that is what would control the stability of rpm at idle.
