What causes the emissions light to illuminate?

[Steve vRS]

If I were to fit a sports cat that resulted in the emissions light coming on and left the light on, what other faults could be hidden?

Steve

 

[Serg]

dont think a sports cat will bring on the light. as there is still a cat there so the emissions will still be in the 'limit'

 

[LegoHead]

coil failures

 

[Steve vRS]

don't think a sports cat will bring on the light. as there is still a cat there so the emissions will still be in the 'limit'

Apparently a 100 cell cat will still trigger a light.

What I mean by the question is that if your emission light is on due to a known reason, what other potentially damaging faults could be hidden?

Steve

 

[16v_jon]

If the light comes on due to a faulty llambda sensor (common) the car will run leaner than normal this may cause problems in the long term

 

[Dink]

Apparently a 100 cell cat will still trigger a light.

What I mean by the question is that if your emission light is on due to a known reason, what other potentially damaging faults could be hidden?

Steve

yep a 100 cell does bring the light on

 

[Neil G]

My 100 cell sports cat has never brought the emsssions light on

 

[Englebert]

Is your sports cat still MOT friendly Neil? I guess it must or otherwise you may as well get a decat!

 

[chris'172]

Hiya, i have a de-cat on mine with both sensors disconnected, since getting a new trip computer fitted the emmision light has came on, it was never on before and the car seems to be going through more fuel than normal. If i was to connect both my sensors back on, what possible harm could it do? Or shall i leave them both disconnected. Basically, what is going to be more harmful, on or off? Cheers, Chris.

 

[16v_jon]

Hiya, i have a de-cat on mine with both sensors disconnected, since getting a new trip computer fitted the emmision light has came on, it was never on before and the car seems to be going through more fuel than normal. If i was to connect both my sensors back on, what possible harm could it do? Or shall i leave them both disconnected. Basically, what is going to be more harmful, on or off? Cheers, Chris.

your sensors must be connected if they are not then the car will run on a base map, due to the lambda not supplying the ecu with any emissions data

 

[chris'172]

Hiya, can you explain please what the base map is and how it affects the car? Cheers, Chris.

 

[Neil G]

Is your sports cat still MOT friendly Neil? I guess it must or otherwise you may as well get a decat!

I hope it is mate...mot in October and I paid 300 notes for it so I would have peace of mind at mot time/roadside checks and no hassle of changing pipes etc.

If it doesn't pass on emissions I am going to have something to say to the manufacturer

 

[-Make-]

If the light comes on due to a faulty llambda sensor (common) the car will run leaner than normal this may cause problems in the long term

I think the second lambda doesnt adjust anything, just showing the damn light. My second lambda is broken and light is on. Not going to buy new one, hell of a expensive part.