A Class emissions - MOT failure

[maldon]

Hello

Our 98 A160 has failed MOT on emissions - four readings were way off. The car failed at garage round the corner, so has been taken to our local indie to see what they can find - they recently sorted the fuel tank probs by replacing the fuel/charcoal filter (can't rememebr which). MOT people thought this may be part of reason - as they said car is running seriously rich.

Anyway, indie has had a look over the car and then took it to their MOT boys - failed agian, but MOT boys suggested to give the car a bit of a run to make sure was properly warmed up. Did that, passed on three but the C02 was way off. That being the case, the indie tried changing the Lambda - once new Lamda was fitted they checked on indies 'small' machine - all looked fine.

Back to MOT people and the readings are all over the place again.

The indie has now got it into local electrical specialist to see if they can find anything.

Indie said he had issues on an A Class recently and the ecu was removed and either fixed or reprogrammed. The Indie guys are trying find out from their customer where he sent the ECU.

So, do we think is really ECU or could there be any other issues that need to be sorted to get the readings back to being stable and within limits for the MOT?

Since the car is getting on I don't take it to the Stealers - I don't really ant to get them involved - but could it be worthwhile taking it along for a check on their equipment? I sort of get the feeling they'll just want to stick an ECU on it anyway.

Really boring - car has only done 65k miles like a new pin, has been absolutely brilliant - but am being told could be looking at £1000 for an ECU - which I guess is something like 40% of the value of the car

Any ideas please?

 

[Parrot of Doom]

ECUs can be repaired for a lot less than that. Very unlikely you'll need to buy a new one.

 

[C220GJS]

Here's one you could try;http://www.tunemycar.com/.

 

[maldon]

PoD - GJS

Thanks for your input - no news back from the Mainly Mercs lads on what took place at their auto electrical place.

 

[maldon]

OK, seems the ECU is the problem - it is not switching the lamda to control emsissions - part no is listed on the 'tunemycar' site from GJS.

Thanks again - will keep you posted.

 

[mattkh]

OK, seems the ECU is the problem - it is not switching the lamda to control emsissions -.

HI
I would start with the Lambda first, that will be cheaper than the ECU, and most likely to be worn out.

 

[maldon]

Matt

Thanks for the tip- we have been down that route - new Lamda was fitted but on re-testing the car failed on all four emissions (having prev passed three witrh only c02 being off spec). It has been taken off and not charged for -

The fault code was, when I checked, 0170, which the lads from the ECU shop had predicted.

The rebuild is three huindred quid delivered witha two year warranty.

Hopefully will have the part back for Friday.

 

[maldon]

Further complications: The people at tunemycar checked the MAF/ECU and found no fault at all with the unit.

Interestingly, the MAF is generally the problem here - they have had five units of the same part number into them in a single day this week - all same problem.

The part is being shipped back. Very good service - the charge is £35 quid for the check up, so no complaints there.

The tech guy at tunemy car said the co2 reading was something like 10x what it should be and that the car must be being fed a seriously rich mixture. The Mrs says she has not noticed any change in mpg/having to fill the car up more often.

As said, we have had the charcoal and fuel filters changed recently - whether this is part of the problem I don't know.

Will be speaking to MainlyMercs when they get in this morning to report findings on the MAF/ECU to see if they can come up with any ideas.

I did wonder whether by merely plugging the part into the testing equipment if this would perhaps trigger a kind of factory reset - but tunemycar thought not.

They feel we are still stuck with the engine being provided with way too much fuel.

Appreciate any ideas / feedback.

 

[mattkh]

Further complications: The people at tunemycar checked the MAF/ECU and found no fault at all with the unit.Appreciate any ideas / feedback.

Hi
Happy for you that the ECU proved OK which is what I suspected.
How brittle are the wires to the Lambda ?
I am thinking it is the cable from the ECU to the Lambda.

 

[maldon]

Don't know Matt. The car is still with the Mainly Mercs lads.

I'll check with them.

Thanks for the tip.