Emissions failure

[dss123]

Hi Guys,

Pride and joy just failed MOT on emissions (lambda only) C02 and HC fine - very low readings.

I remember previous posts about high lambda readings being traced to faulty lambda sensor.

Garage guy said it could also be leaking exhaust?

Please pardon my ignorance, but where is this sensor? Is it easy to replace.

Also I have a cat replacement pipe normally and fitted a cat for the MOT. Should I have reset the ECU or something? - again vague memory from a previous post.

Help please!


All the best


Dunc

[NJS25]

Hi there,

It is worth clarifying the tolerance the garage was measuring to. At my recent MOT test the mechanic was checking to a default level, since the elise does not appear on the current government issued chart.

I seem to recall he was checking to the standard upper limit of 1.03, whereas the Rover 1.8 has an upper limit of 1.09 IIRC.

Worth checking the testing station are using the correct tolerances. As I understand it all new vehicles must conform to the 1.03 upper limit, whereas older vehicles vary dependant upon the year of introduction.

Anyone out there please feel free to correct me if I have misunderstood the regulations, or confirm as necessary.

Regards, Neil

[dss123]

Thanks for that Neil,

I've checked that and according to the print-out, the limit he was testing to was 0.95 at 2450 rpm and 1.09 at 3050 rpm so it seems as though he was not being overly harsh.

In any case mine came in at 1.13 first time round and 1.11 second time round, at normal idle it was 0.01.

C0 was .01 and HC was 2.0! (both very very low)

I've done some research and symptoms seem to be pointing towards the sensor. I've been getting poor miles to the gallon recently and noticed the orange "engine check" light coming on now and again.

The car is 4 years old and it's done 30k so I guess it's due one. Didn't realise how expensive they were though - ouch!

Hopefully sort it all out this week.

Dunc

[LOTOPETE]

HI as i have the daily task of fixing these cars the main point here is use genuine lamba sensor as we have tried various makes inc the so called original fit suppliers.had one case where fitted three sensors before fitting genuine one may be bit dearer but we will not fit anything else now.You can use rover equiv as they are the same but not much diff in price.

When fitting new one break of old one leaving threaded part in exhaust you can then use normal socket and bar to remove(you will find that the proper lamba sockets do not make job any easier they are very tight)you can refit and get it tight enough with normal open end spanner.

As regards your cat no mods req to ECU with or without cat.

Good Luck PETE