Where is the Lambda valve 1997 C200 Auto

[rhino8572]

I have just had an emmission check after my recent problems and my car would fail the MOT.

I have just taken out the plugs and noticed sooty deposits on the electrodes, and also sooty deposits in the exaust.

I am guessing now from reading the forum its my Lambda valve, is this an DIY job, is it easy and more importantly where is the sensor. I'm not too bad at maintainance but if it is a big job then I'll get it booked in straight away.

Is the dealer the best place to get a sensor or are there aftermarket pattern sensors available.

Thanks for any help in advance.

1997-C200 - Classic - Auto - Petrol.

 

[eric242340]

I have just had an emmission check after my recent problems and my car would fail the MOT.

I have just taken out the plugs and noticed sooty deposits on the electrodes, and also sooty deposits in the exaust.

I am guessing now from reading the forum its my Lambda valve, is this an DIY job, is it easy and more importantly where is the sensor. I'm not too bad at maintainance but if it is a big job then I'll get it booked in straight away.

Is the dealer the best place to get a sensor or are there aftermarket pattern sensors available.

Thanks for any help in advance.

1997-C200 - Classic - Auto - Petrol.

Your car failed because it is over-fueling. The Lambda sensor is not at fault, it simply senses too rich a mixture. Have your fuel system serviced and A presto it will pass the CO test.

 

[television]

If the Lambda has failed or contaminated then yes the engine will over fuel as it is sending the wrong info back to the main ECU, The MAF can do the same.

Malcolm

 

[eric242340]

If the Lambda has failed or contaminated then yes the engine will over fuel as it is sending the wrong info back to the main ECU, The MAF can do the same.

Malcolm

Correct Malcolm, but the 02 or Lambda sensors dont often fail, its usually a sign of an engine management problem. Having said this they do sometimes fail but very rare.

 

[rhino8572]

Thanks guys, I have a new MAF this is not the problem, What needs to be done for a fuel system service?

Is the fuel system service a main dealer job, would a faulty lambda give any more symptoms (it is a thirsty little thing of late).

Thanks

 

[eric242340]

Thanks guys, I have a new MAF this is not the problem, What needs to be done for a fuel system service?

Is the fuel system service a main dealer job, would a faulty lambda give any more symptoms (it is a thirsty little thing of late).

Thanks

Of course its thirsty, its over fueling. And why did you replace the MAF? sounds like this has been an on going problem.:?:

 

[rhino8572]

Hi Eric
I took the car to a MB dealer who diagnosed the MAF was at fault as I had trouble starting the car and had a loss of power.

This resolved the problem and all was well the car was running great however this problem has arisen since.

What is involved in a fuel system service I've just had a full service (a month ago), does it need to go on the diagnostics, I obviously want to sort this ASAP, any further help you can provide would be appreciated.

 

[eric242340]

Hi Eric
I took the car to a MB dealer who diagnosed the MAF was at fault as I had trouble starting the car and had a loss of power.

This resolved the problem and all was well the car was running great however this problem has arisen since.

What is involved in a fuel system service I've just had a full service (a month ago), does it need to go on the diagnostics, I obviously want to sort this ASAP, any further help you can provide would be appreciated.

A fuel service is simply a clean/replacement of the fuel filter, and a fuel injector clean also an inspection of the air filter and all associated parts (this is an inspection of anything that can cause over fueling) and yes, the test equipment must be used. What you are playing with here is not a DIY job, sorry to say. It is possible that the Lambda sensor is at fault, but in my experience, unlikely. So dont waste money on this.

 

[rhino8572]

Once again thank you for your help, I'll get this arranged straight away.

I appreciate what you all do on this site, its good to know there are people out there who can help people like me.

 

[television]

Correct Malcolm, but the 02 or Lambda sensors dont often fail, its usually a sign of an engine management problem. Having said this they do sometimes fail but very rare.

Eric Sorry but they do Fail,hence the cars stopping during the fuel contamination crisis.

Apart from this the only other thing that can alter the mixture has been changed.
This is why it is always recomended that a new one be fitted if you have a new CAT. and CATs fail often because the engine is allowed to over fuel.

Malcolm

 

[Ultymate]

Malcolm I have to disagree here it is very rare for Lambda probes to fail, I know this recent incident of fuel contamination has led to many failures but fuel contamination with silicones is previously unknown. My experience is that Lambda probes are probably one of the most reliable sensors found on the modern engine management systems, particularly if you take into account the extremely hostle conditions the Lambda works under. I have seen many cases where petrol engines have been run on diesel and their Lambda sesors have been ok. Far more unreliable are temperature sensors and MAF sensors.:???:

 

[television]

Malcolm I have to disagree here it is very rare for Lambda probes to fail, I know this recent incident of fuel contamination has led to many failures but fuel contamination with silicones is previously unknown. My experience is that Lambda probes are probably one of the most reliable sensors found on the modern engine management systems, particularly if you take into account the extremely hostle conditions the Lambda works under. I have seen many cases where petrol engines have been run on diesel and their Lambda sesors have been ok. Far more unreliable are temperature sensors and MAF sensors.:???:

Thats OK I do not mind if you disagree. The point is that something has gone wrong on this engine, any sensor can fail, the Lmbda does not come into below 300c and should not be measured under that temperture.

The lmbda can swing the mixture more than any other component, the water temp and air temp are easy to measure.

I does not help if you have an car in front of you with the big ends knocking, and then say well the big ends never knock on this engine, something is wrong, and the Lmbda ia no more reliable or unreliable than any other component or sensor.

Malcolm

 

[stats007]

Malcolm I have to disagree here it is very rare for Lambda probes to fail, I know this recent incident of fuel contamination has led to many failures but fuel contamination with silicones is previously unknown. My experience is that Lambda probes are probably one of the most reliable sensors found on the modern engine management systems, particularly if you take into account the extremely hostle conditions the Lambda works under. I have seen many cases where petrol engines have been run on diesel and their Lambda sesors have been ok. Far more unreliable are temperature sensors and MAF sensors.:???:

I'll have to disagree with you . I have seen a lot of lambda sensors on Mercedes fail.

 

[kth286]

Two critical items for correct fuelling (time open for electronic fuel injectors)

will be lambda probe (oxygen sensor) and engine coolant sensor being correct for given engine temperature.

It is recognised that the lambda probes lose their effectiveness at higher mileages and are really a service item (replacement) on that generation car.

It is very common for the coolant temperature sensors to go out of spec also.

£80 for lambda, from dealer I guess and perhaps £14 for coolant sensor.

Lambda in exhaust pipe and coolant sensor in head.

Do codes show anything ?

Always do an emissions test with hot hot engine. Drive the long way round to the test station to ensure engine fully up to temp.

 

[television]

Just adding to Kths post both Air and Temp sensors are so easy to check,when hot they drop to around 50Ω to know if its good or bad these things are around 5kΩ in the cold state, if they do not drop below IkΩ when hot they are faulty. the easy way is to short the sensor to ground where they will be at the hottest setting, also the weakest.

This giude is good enough for rough testing.

malcolm

 

[rhino8572]

Malcolm

Looks like you were right, I've had it checked out today and I'm told there is a problem with the "heating element part" of the O2 sensor, there were certainly plenty of error codes on the diagnostic computer.

It looks as though it will need a new O2 sensor, but I'm quoted £195 + VAT from the MB dealer, I'm not sure this is a slip with the keyboard but it sounds a lot to me, is there any way of identifying the part number without taking the sensor our, I want to make sure:

1) I ask for the right part for the car, I am led to believe the sensor that is used is the one for the W202 and can be also used for 94-00 year range C200Classic Auto.

2) I am not getting ripped off.

Thanks Malcolm and Eric for the help.

Dean

 

[television]

item 80 -83

http://www.detali.ru/cat/oem_mb2.as....418&VIN=*&CT=M&cat=19K&SID=14&SGR=060&SGN=03

Check it out to see if it is the same

Malcolm

 

[C220GJS]

Eurocarparts stock the part you need;http://www.eurocarparts.com/ecommerce/Search_Results.asp ;
Very accessable on your engine as it sits on the top of the exhaust manifold.

 

[bibamus]

I got mine from here.... http://www.lambdasensor.com/
Genuine Bosch, £65 delivered and took me about 10 minutes to fit ( W202 C180, they even grease the thread for you!) I assume yours will be in the same place as mine, on the exhaust manifold, access was from under the car with a spanner.
As has been said before, they are a service item and have a useful life of about 30,000 miles after which they can start to deteriorate.

Allan

 

[kth286]

Dean

I think you misheard the dealer as the correct listed price is £109.44 + Vat.

Always get the dealer one, as there are often different versions depending on the car spec. Do not get a generic one as it will not be optimised to your car spec.

Always quote the VIN to the dealer to ensure you get the correct one.

You should get a discount of perhaps 5% or 10% if you ask, and that will also reduce your VAT.