emissions sensor with new exhuast

OpenToSuggestions · 22 Apr 2007 at 22:08

when i first got my micra 18 months ago the emisions sensor on the manifold was buggered (no idea which one as there are two sensors), it kept having a light on the dash saying my cars giving out to much dirt.

so, my question is. If you increase the performance of a car, wether it being induction filter, new manifold, or even performance camshafts, how come the sensor deosnt come on?? as technically more dirt will be passing through the exhaust per second.

Also, would adding the above stuff (especially a performance cat) make the car fail its MOT, as your car would be giving out more co2 than the standard model should be?

just wondering here i know you guys know the answers

mglover

dalin80 · 22 Apr 2007 at 22:14

that would be the lambda sensor for sensing oxygen rich/lean balance.

the light will come on when its readings are out of accepted bounds, most tuning bits wont alter the fueling too greatly allowing the ECU to compensate keeping the balance in bounds.

a good performance cat shouldnt fail a mot, if it were it wouldnt be a cat it would just be a straight-through pipe.

i doubt a performance cat would make any performance difference to a micra, save your money.

Dogbreath · 22 Apr 2007 at 22:18

mglover070588 said:
Also, would adding the above stuff (especially a performance cat) make the car fail its MOT, as your car would be giving out more co2 than the standard model should be?

CO2 isn't even measured at the MOT!

OpenToSuggestions · 22 Apr 2007 at 22:25

lol dont worry im not chavvin the micra im just being curious

just made me think, if my sensor came on before just because it was wrongly seated (or something the garage did it not me) then surely if you do an uber mod like a turbo then its going to be set off

OpenToSuggestions · 22 Apr 2007 at 22:27

Dogbreath said:
CO2 isn't even measured at the MOT!

i thought emmisions where tested?? i might be wrong though

realscot · 22 Apr 2007 at 22:34

They check CO, HC, and Lambda. (dont ask me what CO and HC stand for and for that matter what the hell lambda is?!!)

Just looking at my printout from my MOT 2 weeks ago.
My CO was 0.01% (0.30 allowed on fast idle and 0.50 on natural idle)
My HC was 4ppm (upto 200ppm allowed)
My Lambda was 1.00 (anything from 0.97 to 1.03 allowed)

I've changed a few things on the engine for performance etc and this week will be sticking on a lovely new stainless 4-2-1 manifold and doing away with the cat (till next mot)
For the fun of it though we're gonna try emissions testing the car without a cat to see just how much it's doing for the enviroment.

OpenToSuggestions · 22 Apr 2007 at 22:38

actually makes me wonder why i even need a cat converter as even if the car was tuned to hell it wouldnt be as bad a a mum doing a school run in a 4x4 3litre v6 twin turbo

Clarkey · 23 Apr 2007 at 00:25

CO = Carbon monoxide. HC = Hydrocarbons.

dalin80 · 23 Apr 2007 at 13:29

and as we all should know hydro-carbons = fuel

co2 is measured at the mot by many testing machines but isnt subject to the same criteria, our machine also measures No which isnt required for the uk.

lambda is a actually oxygen, the oxygen in the exhaust allows the metal in the lambda sensor to 'create' electricity. zirconium dioxide if memory serves, the ecu uses this voltage to help control the fuelling.

the reason ecu's and injections systems are added to cars today is solely for environmental reasons, keep the engine running with the least emissions possible, the fact that a good set-up adds power is merely a side effect.