1986 560SL, 60k miles. Stumbles and sputters once it warms up. No check engine light. Runs great when cold but as soon as it hits about 60 degrees C becomes undriveable. I thought it was a fuel delivery problem, Changed all fuel filters (3) and old fuel lines. No luck. Checked fuel pressures. Perfect. (0.4 difference) Noticed that even when hot the car would drive NORMAL when I floored it and engaged the kickdown. (Haven't figured this out yet??) stumped. Changed the Oxygen sensor. PROBLEM SOLVED! I had no idea the O2 sensor could disable the car like this. I guess it was reading rich and severely leaning out the engine to the point of being undriveable. Thanks Pierre for your AMAZING insight and support keeping our classics alive. Jed (inDetroit)
The on/off ratio and impulse counter where the first diagnostic tools used . The on/off ratio tester was used to double check the fuel system on every cars that came in , even for an oil change .
This looks like one of those scenarios where for diagnostic purposes, putting the computer in fail-safe or emergency mode by disconnecting the o2 to see how the car responds would make sense. Thanks for posting and all the best for 2019!
I agree with your comments most of the time. My first Mercedes was a 200D. It was slow to reach 100 km/h and would not always start on one of those cold winter morning that we have in Canada. But i loved that car and could not sell it even when I had a Citroen SW and a few Volvo before coming back to a 300e. Mercedes, old ones are still my favourites but only by a small margin to Volvo. I would say that they are the two best car ever manufactured.
I’d like to know what equivalents there are to Mercedes tools. From reading my service shop manuals they are mentioned a lot! Would be neat to find a list of substitutes. The Holy Grail of Mercedes is to find a garage sale with tons of Mercedes tools! Also how to use the diagnostic ports. I’m familiar with using the break out box for Ford products and scan tools on the EEC 4 systems. Circa 1995. I learned on the Lincoln Mach VIII. So I’d relate it to that. I really haven’t had to pull any trouble codes on my cars since ‘99. I know the classic Benzes I have don’t have trouble codes of sorts. But it would be really satisfying to diagnose or observe proper operation that way. Observing proper operation really floats my boat. Very fulfilling. I’ve seen guys on Benzworld using oscilloscopes on a 450SL ignition system. My husband’s dad was an audio-visual tech and had one on his desk for years- he passed away a long time ago.
The best way to find mercedes tools is to find a foreign car repair shop, usually run by a retiring owner, and buying their tools. The equivalents of some of these tools don't exist, but I find that they can be replicated if you understand what the purpose of the tool is. There was a tool guide that mercedes published, with a picture and description of each tool.
question: is the O2 only sensor play role on formation of DC percentage ? what about TPS sensor, airflow potentiometer, altitude pressure sensor and also coolant temp sensor Thank you !!
Hello, I have C123 280ce MB, 1978. It seems it had an o2 sensor which was hanging loose when I lifted the car, and it was broken. Maybe you know what is the replacement no. for this part. And if it is original for such year? Thank you!
I have a 300ce 1989. It has intermittent stalling issues and now the check engine light is on. I was wondering would replacing the oxygen sensor fix it? The fuel mixture was just enriched not long ago, so the stalling became less of a problem but still does it. Now the car won’t pass smog here in California. I’m guessing if I replace the O2 sensor will it all go back to normal? And is that a good way to figure if the car needs a new CAT?
I own a 1991 300ce I'm have problems with high petrol usage,19 litres per 100, I am also experiencing when starting the car that the engine doesn't run smoothly for a few seconds then whilst driving it seems normal,on tick over it runs with a wave, could it be the oxygen sensor as it's never been changed,also you can smell petrol from the exhaust.
Pierre thanks for the video. I've been researching about a w124 230E which I'm not quite sure of the manufacturing date by virtue of the VIN (weirdly). So I've worked on the EHA valve and related components but I see the O2 sensor wire is destroyed and what remains are 3 stumps near the sensor itself at the exhaust manifold. The vehicle runs great but consumes a bit of gas. Any ideas about the 230E?
I have a 1991 500 sl with a bad vacuum leak at intake manifold gaskets ,I got a 02 sensor code, changed the o2 sensor, still have code 17 o2 sensor, which comes on in a couple miles. The vacuum leak has been there for years and passed smog several times times. Do you think that I have a bad sensor wire or just more vacuum leaks which just too bad now. And where does the o2 wire go? Where is the computer?
for generation 1 cars, such as my euro 500sec/sel with the CIS system is there any need for the O2 sensor. ..We have been trying to get my cars back to how they were leaving factory, removing all the federalization crap....such as Lamda and frequency valve etc. Im wondering how did the cars for german market for gen 1 manage to make fuel mixture adjustments or adjust idle
I have an 1989 190e 2.6 and I have having extreme loss of power around 3k rpm when its warm, when its cold it'll start stumbling to 3k rpm. I have no idea what's going on and was hoping it was maybe just the oxygen sensor but I can't seem to pinpoint the issue. I would be very grateful if you could look into my problem and help me out, Thank you.
Hey man i need some info or guide with my 93 190e 2.6. When the engine warms up or closed loop it starts misfiring horribly. I tried adjusting the lambda on duty cycle. (Red plug on pin 3) i know the black should go to pin 2 but as soon as i plug the black lead to 3 the readings goes away. But anyways i adjusted it that way. Any pointers why its happening tho?
Hello, Alexis Montealegre and thank YOU so much for your question(s), we want to answer you as quickly as possible. By signing in our Patreon www.patreon.com/thomaspolk page and making a donation of $10 your are assured of a 24 hour email response from Pierre. If you are already a $10 member please mention along with your question.
It has to do with exactly HOW the o2 sensor failed. They can fail in quite a number of different ways, and the rarer failure modes can cause a dramatic running problem. Most of them won't.
Good day Pierre a am from south Africa my name is olso Pierre I have a 1974 350se in my collection it was service an after the service it started over fueling and want to contact you daretly to find out wat koet be rowng Plese
Afternoon, I've been watching your videos recently and they're extremely helpful. Can't thank you enough as the car that once didn't, now runs! I have a couple questions regading the o2 sensor. I have a 1989 190e 2.0 and it doesn't have an o2 sensor or Pin 3 in diagnostics, is that common? Without that not sure how to tine the AF mix. Also the car starts and runs fine but when the temperature gets up to 80 degrees engine stalls, when it cools down it'll start again. Have you experienced anything like that before? Any help is massively appreciated.
Hi F S, A bit late now I'm sure, I had this exact issue (1991 300E24v), a small enough crack in the distributor cap, replaced it and was the whole fix for me!, just to note, I saw the crack months prior but tiny crack it was I left it alone except for cleaning the contacts, 6 months later, after two weeks sitting up in humid weather the stalling at temperature occurred, I took my 420SE's distributor crack more seriously now (swapped it immediately) and fuel ratio test when engine temp reached shows static 50% indicating that the o2 sensor had given up, one ordered as suffering problems as Pierre suggested and seemingly went into full rich mode which I tuned back for now as the smell and plumes of petrol vapour out the exhaust is not a nice look at €2 a litre currently, ashamedly I did smile whenever a tesla pulled up behind me :)
Hi, I have a question about my Mercedes Benz w201, 190E, 1.8, 1990, and engine is running like it works with 3 cylinders and shaking and nit pulling enough, so what can be an problem about this except spark plugs, is it possible to be fuel injectors that causing this problem, thanks in advance.
Hello, Besim Rexhepi and thank YOU so much for your question(s), we want to answer you as quickly as possible. By signing in our Patreon www.patreon.com/thomaspolk page and making a donation of $10 your are assured of a 24 hour email response from Pierre. If you are already a $10 member please mention along with your question.
Hello Pierre:Should the Oxygen sensor on a W126 be changed as a matter of routine based on age of the car or mileage? I own three W126 vehicles and drive them regularly. ThanksNabeel
My 1990 300SE will start and idle when cold but will run rough and eventually die at operating temp. It seems to run too rich once warmed. Im told it could be an ignition problem.
@@mercedesclassicswithpierre1753 Yes near the firewall. A visual inspection indicates it looks fairly new. Ive only had the car for a month and know very little about its history which makes it all the more difficult to diagnose which parts are old and which parts are not.
@@mercedesclassicswithpierre1753 Another symptom I forgot to mention, when it reaches operating temperature and starts to run rough, it also starts to spray some black soot type of substance from the tail pipe......
@@mercedesclassicswithpierre1753 I already have the regulator exposed. Im just still analyzing the regulator to see where it is bent. nothing looks bent and it is hitting both stops so i just need to keep investigating.
@@pinzgauernorcal did you connect everything at raise and lower the window? there is a "crane arm" that raises and lowers the window...this is usually where the trouble strikes...
@@mercedesclassicswithpierre1753 yeah the crane arm has a small pivot arm and i compared mine to photos online and for some reason the small pivot arm on mine it extended upward instead of downward, also somone used really thick grease and it is gumming the whole thing up.
if you remove the motor from the regulator and run the window up and down, can you see where the issue is the the regulator? any little bend will affect it.
1986 560SL, 60k miles. Stumbles and sputters once it warms up. No check engine light. Runs great when cold but as soon as it hits about 60 degrees C becomes undriveable. I thought it was a fuel delivery problem, Changed all fuel filters (3) and old fuel lines. No luck. Checked fuel pressures. Perfect. (0.4 difference) Noticed that even when hot the car would drive NORMAL when I floored it and engaged the kickdown. (Haven't figured this out yet??) stumped. Changed the Oxygen sensor.
PROBLEM SOLVED!
I had no idea the O2 sensor could disable the car like this. I guess it was reading rich and severely leaning out the engine to the point of being undriveable. Thanks Pierre for your AMAZING insight and support keeping our classics alive. Jed (inDetroit)
The on/off ratio and impulse counter where the first diagnostic tools used . The on/off ratio tester was used to double check the fuel system on every cars that came in , even for an oil change .
This looks like one of those scenarios where for diagnostic purposes, putting the computer in fail-safe or emergency mode by disconnecting the o2 to see how the car responds would make sense. Thanks for posting and all the best for 2019!
when you unplug it, it goes full rich.
@@mercedesclassicswithpierre1753 yes both you can adust mixture by manually with Ke Jetronic .you don't need o2 sensor any more? Lol
I agree with your comments most of the time. My first Mercedes was a 200D. It was slow to reach 100 km/h and would not always start on one of those cold winter morning that we have in Canada. But i loved that car and could not sell it even when I had a Citroen SW and a few Volvo before coming back to a 300e. Mercedes, old ones are still my favourites but only by a small margin to Volvo. I would say that they are the two best car ever manufactured.
it might amuse you to hear thsat I learned to drive stick on a volvo 240DL!
I’d like to know what equivalents there are to Mercedes tools. From reading my service shop manuals they are mentioned a lot! Would be neat to find a list of substitutes. The Holy Grail of Mercedes is to find a garage sale with tons of Mercedes tools!
Also how to use the diagnostic ports. I’m familiar with using the break out box for Ford products and scan tools on the EEC 4 systems. Circa 1995. I learned on the Lincoln Mach VIII. So I’d relate it to that. I really haven’t had to pull any trouble codes on my cars since ‘99. I know the classic Benzes I have don’t have trouble codes of sorts. But it would be really satisfying to diagnose or observe proper operation that way. Observing proper operation really floats my boat. Very fulfilling.
I’ve seen guys on Benzworld using oscilloscopes on a 450SL ignition system. My husband’s dad was an audio-visual tech and had one on his desk for years- he passed away a long time ago.
The best way to find mercedes tools is to find a foreign car repair shop, usually run by a retiring owner, and buying their tools. The equivalents of some of these tools don't exist, but I find that they can be replicated if you understand what the purpose of the tool is. There was a tool guide that mercedes published, with a picture and description of each tool.
Mercedes Classic with Pierre Hedary thanks! I’ve been studying the website samstag sales .com. Interesting tools there.
Mercedes Classic with Pierre Hedary thanks! I’ve been studying the website samstag sales .com. Interesting tools there.
Do all the 300SE have O2 sensors? I have a 1986 Euro models with no catalyst so I thought there would be no O2 sensor?
question: is the O2 only sensor play role on formation of DC percentage ?
what about TPS sensor, airflow potentiometer, altitude pressure sensor and also coolant temp sensor
Thank you !!
🎉Happy New Year Pierre 🍾 I appreciate all of the great advice and knowledge that you share!
thank you!!!! happy new year!
Hello,
I have C123 280ce MB, 1978. It seems it had an o2 sensor which was hanging loose when I lifted the car, and it was broken. Maybe you know what is the replacement no. for this part. And if it is original for such year? Thank you!
I'd love to see something on the on/off ratio and how to take the readings. I've never had any luck getting a meaningful result.
I will take this into consideration. In fact, i have been trying to figure out a way to do this more effectively
I had an oxygen sensor code check engine light, on my 1990 300TE that went away after EHA valve replacement.
you need to find what the "code" says
I had the code from the beginning, that is what started the search. It is all related to the fuel system.@@Uc9uE3pKsS6uQ
I have a 300ce 1989. It has intermittent stalling issues and now the check engine light is on. I was wondering would replacing the oxygen sensor fix it? The fuel mixture was just enriched not long ago, so the stalling became less of a problem but still does it. Now the car won’t pass smog here in California. I’m guessing if I replace the O2 sensor will it all go back to normal? And is that a good way to figure if the car needs a new CAT?
Any luck ? I have a California mercedes 190e with check engine option
I own a 1991 300ce I'm have problems with high petrol usage,19 litres per 100, I am also experiencing when starting the car that the engine doesn't run smoothly for a few seconds then whilst driving it seems normal,on tick over it runs with a wave, could it be the oxygen sensor as it's never been changed,also you can smell petrol from the exhaust.
Does it need to be a Bosch direct fitment Oxygen sensor or any universal oxygen sensor will work ?
Pierre thanks for the video. I've been researching about a w124 230E which I'm not quite sure of the manufacturing date by virtue of the VIN (weirdly). So I've worked on the EHA valve and related components but I see the O2 sensor wire is destroyed and what remains are 3 stumps near the sensor itself at the exhaust manifold. The vehicle runs great but consumes a bit of gas. Any ideas about the 230E?
I have a 1991 500 sl with a bad vacuum leak at intake manifold gaskets ,I got a 02 sensor code, changed the o2 sensor, still have code 17 o2 sensor, which comes on in a couple miles. The vacuum leak has been there for years and passed smog several times times. Do you think that I have a bad sensor wire or just more vacuum leaks which just too bad now. And where does the o2 wire go? Where is the computer?
yes they do
this isn't the SD but the SE, SD's don't have an ox sensor.
it was a typo...sorry
for generation 1 cars, such as my euro 500sec/sel with the CIS system is there any need for the O2 sensor. ..We have been trying to get my cars back to how they were leaving factory, removing all the federalization crap....such as Lamda and frequency valve etc. Im wondering how did the cars for german market for gen 1 manage to make fuel mixture adjustments or adjust idle
o2 sensor was never installed on the euro cars, nor was a frequency valve, or a catalyst, unless otherwise specified with a sticker on the car.
@@mercedesclassicswithpierre1753 right so how does one make adjustments and assess measurements to air fuel, rich or lean, and idle
I have an 1989 190e 2.6 and I have having extreme loss of power around 3k rpm when its warm, when its cold it'll start stumbling to 3k rpm. I have no idea what's going on and was hoping it was maybe just the oxygen sensor but I can't seem to pinpoint the issue. I would be very grateful if you could look into my problem and help me out, Thank you.
Hey man i need some info or guide with my 93 190e 2.6. When the engine warms up or closed loop it starts misfiring horribly. I tried adjusting the lambda on duty cycle. (Red plug on pin 3) i know the black should go to pin 2 but as soon as i plug the black lead to 3 the readings goes away. But anyways i adjusted it that way. Any pointers why its happening tho?
Hello, Alexis Montealegre and thank YOU so much for your question(s), we want to answer you as quickly as possible.
By signing in our Patreon www.patreon.com/thomaspolk page and making a donation of $10 your are assured of a 24 hour email response from Pierre.
If you are already a $10 member please mention along with your question.
It has to do with exactly HOW the o2 sensor failed. They can fail in quite a number of different ways, and the rarer failure modes can cause a dramatic running problem. Most of them won't.
Good day Pierre a am from south Africa my name is olso Pierre I have a 1974 350se in my collection it was service an after the service it started over fueling and want to contact you daretly to find out wat koet be rowng
Plese
Afternoon, I've been watching your videos recently and they're extremely helpful. Can't thank you enough as the car that once didn't, now runs!
I have a couple questions regading the o2 sensor. I have a 1989 190e 2.0 and it doesn't have an o2 sensor or Pin 3 in diagnostics, is that common? Without that not sure how to tine the AF mix.
Also the car starts and runs fine but when the temperature gets up to 80 degrees engine stalls, when it cools down it'll start again. Have you experienced anything like that before? Any help is massively appreciated.
Hi F S, A bit late now I'm sure, I had this exact issue (1991 300E24v), a small enough crack in the distributor cap, replaced it and was the whole fix for me!, just to note, I saw the crack months prior but tiny crack it was I left it alone except for cleaning the contacts, 6 months later, after two weeks sitting up in humid weather the stalling at temperature occurred,
I took my 420SE's distributor crack more seriously now (swapped it immediately) and fuel ratio test when engine temp reached shows static 50% indicating that the o2 sensor had given up, one ordered as suffering problems as Pierre suggested and seemingly went into full rich mode which I tuned back for now as the smell and plumes of petrol vapour out the exhaust is not a nice look at €2 a litre currently, ashamedly I did smile whenever a tesla pulled up behind me :)
Hi, I have a question about my Mercedes Benz w201, 190E, 1.8, 1990, and engine is running like it works with 3 cylinders and shaking and nit pulling enough, so what can be an problem about this except spark plugs, is it possible to be fuel injectors that causing this problem, thanks in advance.
Hello, Besim Rexhepi and thank YOU so much for your question(s), we want to answer you as quickly as possible.
By signing in our Patreon www.patreon.com/thomaspolk page and making a donation of $10 your are assured of a 24 hour email response from Pierre.
If you are already a $10 member please mention along with your question.
My 230e high revs in park and in neutral at 2000rpms . But when in drive it changes to 1000rpms
Hello Pierre:Should the Oxygen sensor on a W126 be changed as a matter of routine based on age of the car or mileage? I own three W126 vehicles and drive them regularly. ThanksNabeel
I think its a good idea.
My 1990 300SE will start and idle when cold but will run rough and eventually die at operating temp. It seems to run too rich once warmed. Im told it could be an ignition problem.
how old is your over voltage protection relay? this sounds like the issue
@@mercedesclassicswithpierre1753 Thank you I will look into that.
@@timebandit71 its got a red top, located next to the fuel pump relay and fuse box
@@mercedesclassicswithpierre1753 Yes near the firewall. A visual inspection indicates it looks fairly new. Ive only had the car for a month and know very little about its history which makes it all the more difficult to diagnose which parts are old and which parts are not.
@@mercedesclassicswithpierre1753 Another symptom I forgot to mention, when it reaches operating temperature and starts to run rough, it also starts to spray some black soot type of substance from the tail pipe......
Do the om617’s have o2 sensors?
no he made a mistake he is talking about a gas car not diesel.
no...it was a typo..sorry
Im trying to get the rear windows of my 300CD to roll down all the way it seems that the regulator arm is down instead of up
the regulator arm is bent...time to take out the back seat, the rear interior panel....and repair the regulator
@@mercedesclassicswithpierre1753 I already have the regulator exposed. Im just still analyzing the regulator to see where it is bent. nothing looks bent and it is hitting both stops so i just need to keep investigating.
@@pinzgauernorcal did you connect everything at raise and lower the window? there is a "crane arm" that raises and lowers the window...this is usually where the trouble strikes...
@@mercedesclassicswithpierre1753 yeah the crane arm has a small pivot arm and i compared mine to photos online and for some reason the small pivot arm on mine it extended upward instead of downward, also somone used really thick grease and it is gumming the whole thing up.
if you remove the motor from the regulator and run the window up and down, can you see where the issue is the the regulator? any little bend will affect it.
I hope Pierre isn't paying for these videos to be made. Title is wrong and the photo is a W124 300CE and he is talking about a W126 300SE.
i changed the title...Thomas usually enters the titles...
3:45
3:08 - 3:10
1989 420SEL CONNECTION FOR OXYGENSENSOR INDERR PASSEMGER CARPET CCANT FIND HELP