Off Topic: MOT Emissions Failure; Am I being given the run around

[Sprocket]

Way Off topic, but if anyone can help with any info they can would apreciated.

The wifes car (seat Arosa 1.0S MPi 2002) failed the emissions test with high fast idle lambda, results as follows

CO 0.030% pass
HC 9ppm pass
Lambda 1.084 fail

Now the engine was running great, No warning lights, and I asked if there were any fault codes recorded (car was in for a service as well but as garages always do, they MOT'd it first), no fault codes registered.

After discussing it with the garage (wednesday afternoon) and leaving it with them to diagnose, after a heated dabate about it NOT being the fault of the cat converter. It took them till 15.30 today to 'diagnose' the fault. The fault was apparently the lambda sensor heater open circuit and it needed a new lambda sensor. They did not have one on the shelf and it would be tomorrow before they could get one in. The wife needs the car to get to work tomorrow. I phoned Andrew Page just round the corner, no more than five minuits walk from the garage. They had  one on the shelf, Bosch OEM replacement. I went round to the garage, got the keys and checked everything before changine the part. The Engine warning light was on, wasnt on when we took the car in(things looking odd in my mind). I replaced the sensor,  the sensor that was on the car was one I fitted last year before the last MOT and was one from the Vems Web shop, no problems. The engine warning light was still on, took it for a run to warm it up and it was then put back on the gas analyser where it failed again on exactly the same thing with what would be considered the exact same readings. I checked the heater resistance on the sensor I removed across pins 3 and 4, 2.7 ohms (I checked the others i have when i got home and they measured around 3.1 ohms) the heater is not open circuit.

Now even lonegr long story short, the garage are telling me that it is because this is not a Seat part, and they have found the cheaper universal type sensors to be no use. I then had a heated debate with them saying that  there will be no difference in parts other than a sticker on the box with a Seat part number on it. I checked the part number with the original factory fitted sensor that I kept and it was identical!!!

One thing I did ask was what the O2 reading was, the mechanic could not tell me, I asked if they had a four gas analyser, other than the MOT unit which didnt give an O2 reading, and he said no. I then asked if there was any calibration required with replacement lambda sensors, and the answer was no, I then asked if the adaptive parrameters would need tuning, and he replied that he couldnt comment much on that, mmm, an answer to the problem maybe???

I have left the car with them so they can fit a propper Seat supper dooper special lambda sensor, that will cost £110 and then £49 to fit it. I asked what would then happen if the problem still exists, whould I still have to pay for the parts faulted and replaced that were not faulty in the first place, yes was the reply.

I am not convinced. I suggested from the very start that the problem could well be a leaky exhaust as the car is now 6 years old and there was an advisory on last years MOT of corrosion on the exhaust, lol, that is mysteriously not on this years advisories. The garage refused to accept this would be the fault saying that the O2 reading was low (wait a minuit, i was told they had no equipment to measure this) and the HCs were low, if there was a leaky exhaust the HC would be high now is it me or is that tatement some what incorrect. Yes if the leak was before the lambda sensor, maybe, but what if its after, where would the extra HC come from?

Sorry for the rant but I am a little anoyed with the response of the garage, A mainstream Seat dealer.

Question , which way will the Lambda read if the heater circuit is non functional?

Lets assume that the sensor is functional and there is no calibration required on these, as they told me there wasnt, other than a leaky exhaust, what would cause a lean condition that the lambda correction wouldnt correct?

I am not a happy bunny, as i can see big holes in the diagnostic procedure and the way they are going about it is going to hurt my wallet. The wife is not happy as she has no car to get to work and had to take today off as well, in the thought that we would have the car back. This is not a difficult to sort problem, but the lax attitude of the garage is irritating. I have to give them some due, they did not charge me for the diagnostics so far as the sensor did not sort the issue, but the service and MOT has so far cost me £230 plus a part that was maybe not required another £94 ( i'll use that on the mini )

This car was bought new, and serviced ant MOT'd yearly at this dealer irespective of mileage.

Any information or advice welcome

Sprox

[Sprocket]

Super Dooper, special VW Lambda sensor fitted and it still failed!! As I knew it would!!

They wanted to replace the Cat, but at £450 +VAT and fitting, i removed the car from the garage, fitted a new back box at a total cost of £38, and got it MOT'd at another garage. It passed first time with a Lambda of 1.009.

The motor trade in this country is rotten to the bone! they are all out to rip you off in one way or another! I went to two high street name exhaust centers before I started to get the picture, one said that a leaky exhaust wouldnt matter to emissions, and anyway, they could only replace the whole rear section as the slip joints are on the wrong ends, the other would happily replace the back box, but wanted just as much as the whole rear section from the other place. I went to Andrew Pages again and bought a rear box and fitted it myself!! The back box was the same manufacturer as that the exhaust centers I went to would have fitted, I saw the catalogue they looked in. The slip joint was on the right end!!

If you want somethig doing right, do it yourself

Do not under any circumstance let any garage replace parts with out first showing you the diagnostic evedence that suports why it is faulty. A cat is not a cheap item and once fitted, if the problem is still there, you will still have to pay the bill!!

Rant over, car is fixed with another 12 month ticket.

Please feel free to remove this

[rob@vems.co.uk]

Scary isnt it?  My Dad had shocking service from his Saab dealer, after taking the car back for the 5th time (getting charged each time) he finally wrote a formal letter of complaint, and found that the car was booked in, repaired properly, free of charge.

It would be worth doing the same and writing to the garage owner, quite often they're not aware whats going on in their workshops.

[Jorgen]

Sprockets,

Not that it's of much interest for you when you have it fixed, but others may benefit from some additional information.

The guy at the shop must be new at this, I'm not in any way good at fixing emissions problems on stock engine management systems but the numbers you posted show little indication of a bad lambda sensor. It is the typical tell-tales of a leaky exhaust.

With such low CO and HC the cat is also unlikely to have helped the problem, if CO and HC was high a new cat could possibly have fixed them as well as the lambda, but as there was hardly any excess fuel to burn the cat will not use any oxygen and the lambda will stay more or less unchanged.

Jörgen

[500]

Good to hear you sorted it yourself, I've had similar problems with mainstream garages too which is why I do it all myself now 

And over the VAG parts, recently bought a Touareg for the Mrs to commute in, prop bearing went, sorry sir, you can't change the bearing on those, you need a new prop shaft, that'll be 589 + Labour + Vat please  ffs, it's only done 70k!