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#16
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On your dash, use a flashlight (or not if the symbols are clearly legible) to light up the warning lights. On some cars, particulary earlier ones, I believe that there might have been a "Lambda Sensor" warning light. As to the reliability of these, I don't know. There shouldn't be anything to reset-just plug in (or rewire) the new sensor. The engine reads the correct inputs and adjusts the fueling system accordingly.
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________________________ 2002 Mercedes-Benz E320 4Matic 1995 Mercedes-Benz E320 Wagon 2005 Land Rover LR3 V8 SE 1999 Audi A8 4.2L quattro |
#17
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Correct! The O2 sensor light illuminated on the dash of my erstwhile '84 190E at 30K miles. I asked the dealer how they reset the light. The answer was remove the bulb, which I did without replacing the sensor.
I sold it at 49K, and it passed its title transfer emission test - no problem. Duke |
#18
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[QUOTE=manny]A good O2 sensor can be observed by watching the " cross-counts ", i.e. how many times it switches from rich to lean, in a given time.
Duke 2.6 correctly pointed this out earlier. As an O2 sensor ages, it will get " lazy ", i.e. instead of, say 10 cross-counts/second, it slows donw to, let's say 5 crosscounts. This may not result in the illumination of the Check engine light, but can have an affect on emissions & fuel economy. Bottom line..........it's up to you to decide. [/QUOTE I believe ten "cross counts" is too fast. The typical "period", which would be two cross counts should be about one second. If it's slower than two seconds the sensor may be getting lazy. The actual response time of the sensor is about a tenth of a second, but the system richens very slowly so it doens't get ahead of sensor response time. This is my understanding based on reading about O2 sensors, but I'd welcome anyone's comments who has good info as I have found it difficult to find information on O2 sensor failure modes. Slow response time is one and I also suspect that they may drift off calibration, but have not been able to confirm. Duke |
#19
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on my 190e2.6, the engine began sputtering for no apparent reason and at unpredictable times, when the weather was cold. This was so difficult to diagnose that I left the car at the MB service center. They were able to reproduce the problem, which they traced to a faulty/malfunctioning O2 sensor. This, without the "Check Engine" light coming on, and well below the 60k interval since the time it was last replaced.
Replacing the O2 sensor fixed the problem. The issue here is that the sputtering engine problem can be a safety issue, because it happens with no warning. It almost left me stranded in the middle of an intersection in the lane of oncoming traffic, as I was making a left turn. I had to nurse the car to a safer location until it recovered. This sputtering engine problem happened again years and many kilometers later, again, without the "Check Engine" lamp coming on. I immediately asked my MB service advisor to have the O2 sensor replaced. They placed a note on the service sheet that it was done at the request of the customer. |
#20
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Duke 2.6
In my " simplified " explanation earlier, I just tried to convey a message to " the people ", as to what can be expected from an O2 sensor. Of course the cross-count timing is exaggerated, but the principle of " healthy " vs. " lazy " sensor activity should be understood. Btw, the average DVOM is only averaging the voltage output readings from the sensor, so while it may show activity, it is not necessarily " real time " information.
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2007 C 230 Sport. |
#21
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Quote:
Duke |
#22
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Mike,
I'm assuming that when you say you are reading .2 O2, you are talking about voltage at sensor and not gas reading at tailpipe, because that is a perfect tailpipe reading. If you read a constant .2 volts in open loop, you need to replace the sensor. Don't worry you won't trigger any lights. Peter
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Auto Zentral Ltd. |
#23
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I just put that as an example of a voltage
The question I had was really how do you Know the calibriation of the sensor If in 1988 the .5 volt at a certain co Today may be in 2004 .2 volt with that same sensor????? So thats were I felt just starting with a new sensor would eleminate any guess work of getting wrong reading to the injection system I am just asking If this makes sense The sensor is so old I can't get it loose anyway I am going to hit It with the torch next
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[B]Mike Y. 00 sl500 sport 88 560 sl (sold) |
#24
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Quote:
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Norm in NJ Next oil change at 230,000miles |
#25
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I appreciate all the help from everyone
I feal better now understanding how it works I like your idea on the beer can't go wrong with that move. This sight has a great bunch of people cheers!!! Mike
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[B]Mike Y. 00 sl500 sport 88 560 sl (sold) |
#26
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Mike,
It doesn't matter how old the sensor is. It should always be around .5 volts in either open or closed loop. The only difference being that in closed loop it should sweep back and forth. It would take awhile to explain how the system works, which is why I suggest you do an archive search. There is enough info there to keep you up all night. Or is that nite? Peter
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Auto Zentral Ltd. |
#27
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I finaly got some time to check the voltage at the o2 sensor
disconneced it and took some readings Voltage was at .2 vdc and some times lower under .1vdc if I raced the engine nit went up once in a while to .8vdc But not all the time especially after running for a while Seems like when it got hot it stayed at low voltage Injection check I also checked voltage at termanal x11 terminal 2 & 3 getting .6 v at idle But racing engine I was getting 12.5 vdc What gives???
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[B]Mike Y. 00 sl500 sport 88 560 sl (sold) |
#28
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Sounds like IF you have a 3-wire sensor, the heating element is gone ( the 12 volt side ).
On the old, single wire sensors, you had to rev the bejeepers out of the engine to heat it up. O2 sensors start putting out a valid signal at @ 600 degrees. Many engines will idle at about 450 - 500 deg.
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2007 C 230 Sport. |
#29
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Thanks for the help
I will try to get it out . One other question I have about cam timming I check stretch today Drivers side looks good but Pass side showing 7 degree at the crankshaft to get the marks to line up Is that normal to have the driver side right on and the other cam out that much Should not the driver side be out say 2 degrees fom stretch Or is the cam just out and do they have an offset key for the cam??? or do I need a chain I Know the guides are due at 78,000 Any help is appreciated
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[B]Mike Y. 00 sl500 sport 88 560 sl (sold) Last edited by myanoch; 12-11-2004 at 04:44 PM. |
#30
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This may sound dumb, but what is the O2 sensor and what is it's purpose. If it fails what happens? What if the O2 sensor cable is pinched into, will the car start? Does anyone have a picture of the sensor and cable? Where is it located?
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