Is This A Try-On?

[MSG2004]

To me it does seem suspicious and I would tend to agree as stated above that to offer anything could open a can of worms, even if you feel morally obliged to give the benefit of doubt. What was your impression of the buyer?

There was thread a few weeks ago where I posted that during the previous 25 years I've only sold my car to a garage or WBAC - I'm as honest as the the next person here but I do worry about people coming back and complaining even though the last could of cars I sold privately about/over 25 years ago I made sure I was 100% honest and got the buyer to sign a piece of paper stating "bought as seen and tested."


Year ago, when I part-x my second C class with a MB main dealer, a phone sale, ie they bought the new car to me and took away mine - when I rang them about one of the many problems I was to encounter with my new/sued MB, the sales rep that sold me the new car said something about,
"the EML came on as our driver was driving the car back to..." That was the end of that

Selling to WBAC/etc, no comebacks if you are honest and often a better deal with your new purchase at the garage in my experiences esically if the car is more than a few years old

 

[SpikyMikey]

The question I most want answered, because I can't answer it myself, is how an O2 sensor failure, or even two such, affects the running of a car. Could it cause it to splutter to a halt? Anybody know?

The second message states that "The car is lumpy and noisy where the ECU cannot maintain the correct fuel air mixture" Is that plausible? Anybody know?

A sweeping generalisation maybe, but:
Bad O2 Sensor Symptoms: How to Identify and Address Them
Note the subtle differences between up and downstream sensor failure.

 

[StMarks]

I’m in the it is highly suspicious camp .
I would press for details to lock the purchaser down on his story early on , just in case.
What is the address and name of the garage ?
Get a receipt for the money he paid for the scan and the written down diagnosis .
How far is this garage address from the new owners home ? (Have they a previous relationship)
Is this garage a back street below the radar type place ?

^ This +1 ^
It's almost certainly a chancer, but for your own peace of mind the buyer's inability to supply the above proof should alleviate that concern for you.?

 

[Larkone]

Even simpler - sold as seen therefore no further contact/responses required

 

[Scott_F]

You could ask him to bring the car back to you in order to demonstrate the full nature of the problem and gauge his reaction to your suggestion.

 

[NJSS]

I had a similar experience some years ago. I sold a Land Rover Discovery, with full service history. The purchasers went on a 10 mile test drive & haggled the price down a little.

Two hours after they left I had a 'phone call saying that there was a problem, I can't now remember what, and they had an estimate of £1,200 for essential repairs.

I responded "sold as seen" and I'm not interested.

Some days later I discovered that the purchasers were motor traders & had my former car offered to sale at a decent profit.

I don't believe that there was a problem & am glad that I stood my ground.

 

[Steveml63]

Early cars had a single o2 sensor before the cat.
You could therefore remove the cat and the car ECU would not even know.
Later cars had an o2 sensor before and after the cat.
The one after the cat then measured the effectiveness of the cat and altered the fuel/air mixture accordingly.
If you removed the cat on these vehicles or the downstream 02 sensor failed - then the ECU would get in a mess and the car would not run well

 

[Bellow]

Later cars had an o2 sensor before and after the cat.
The one after the cat then measured the effectiveness of the cat and altered the fuel/air mixture accordingly.

Only an upstream O2 sensor alters fuelling. Downstream is for - as you said - monitoring the effectiveness of the cat.

Back to the OP's question. Without input from the upstream O2 sensors the ECU will resort to a pre-programmed map - as it does when the O2 sensors are too cold to output a signal. Open loop as it is, it will be less effective at controlling mixture but it should run tolerably well.
Simultaneous failure of two O2 sensors? Only if they poisoned them - an unlikely scenario but on them if it happened. Walk and don't look back.

 

[Petrol Pete]

Ask them to send you a screenshot of the Diagnostic machine showing the fault code , them ask them where the garage is that charges just £20 to scan a car that drives in without an appointment (Then post the address on here and that garage will be full of old MB's in no time ! )...

Then tell them to Pi$$ off .

 

[Will]

I must admit I’m not convinced that this is/would be an o2 sensor issue anyway, it might just have flagged that as a symptom but it doesn’t guarantee what the cause is.

Aren’t M272 engines known for timing issues?

But again, unfortunately for the buyer this is academic anyway, unless someone has masked a pre-existing issue and/or lied about it, which I am sure is not the case.

 

[TC350]

Thank you for that. The CLK is a petrol V6, though. Do petrol and diesel engines react the same way to that failure?

When the O2 sensor failed on my petrol C350 (M276 engine) I drove several hundred miles before it was replaced and there was absolutely no change in performance.

 

[Steveml63]

In summary - a simple “‘sorry can’t help you” - then block and ignore would be the most prudent way forward.
If you engage in any conversation - it will make them think you stand a chance of sending them some money!

 

[Petrol Pete]

Or txt them 'Caveat Emptor' ...and goodbye.

 

[poormansporsche]

There's a new fangled phrase that I'm very keen on

Zero £ucks given

Then block em

 

[Petrol Pete]

Or ... " I do believe you have mistaken me for someone who gives a F**K "

 

[SmartAmg]

Or txt them 'Caveat Emptor' ...and goodbye.

They sound like. They wouldn't know what the hell that means.

 

[SmartAmg]

Or ... " I do believe you have mistaken me for someone who gives a F**K "

Sounds good, but the trouble with that is.
I presume they bought it from his house, so they obviously know, where he lives.
They could be totally nutters, for all he knows. So be careful.

 

[Spider10]

They bought it there problem especially at that price point ,afew years ago I bought a corsa vxr and the gearbox exploded on the way home I just laughed about it and thought you get a lemon sooner or later I wouldn't dream of asking for a refund I bought it my problem

 

[st13phil]

Back to the OP's question. Without input from the upstream O2 sensors the ECU will resort to a pre-programmed map - as it does when the O2 sensors are too cold to output a signal. Open loop as it is, it will be less effective at controlling mixture but it should run tolerably well.
Simultaneous failure of two O2 sensors? Only if they poisoned them - an unlikely scenario but on them if it happened. Walk and don't look back.

^This. The simultaneous failure of two sensors is highly unlikely absent external factors so on that basis alone I’d say it’s a try-on.

No need to get aggressive with the purchaser though, just a simple “Sorry to hear that, but it was fine when I owned it and when you drove it away, it was described accurately and I have no further responsibility”.

 

[Gollom]

^This. The simultaneous failure of two sensors is highly unlikely absent external factors so on that basis alone I’d say it’s a try-on.

No need to get aggressive with the purchaser though, just a simple “Sorry to hear that, but it was fine when I owned it and when you drove it away, it was described accurately and I have no further responsibility”.

What he said! ^^ No need (perhaps initially) to get aggressive - seems to be a thing nowadays. Always thought sugar is better than vinegar