Mot Fail High Emissions

[floppydog]

Hi my problem

My Clio mk2 1.2 8v failed mot on emissions :

co2 9.52 %
hc 639ppm
lambda 0.74

I have checked fuel pump pressure running at 3 bar

also ran on computer and lambda ok

Any ideas ? pump, manifold ? injector ? map sensor ?

car starts runs sweet and is giving around 40mpg mixed driving its a 2000 on a w plate

thanks

 

[darrenclio172]

Hi Mate,

Your lambda reading is at 0.74 !! That is way too rich.

Lambda should be 1 (14.7 parts air :1 fuel). 0.74 is around 10:1.

I would be looking for something causing excess fuel. But you are saying you are getting good fuel economy and the lambda is ok ??..... confused

Maybe you are using the right amount of fuel but not enough air giving the rich reading.....have you checked the air filter ?

 

[TheEvilGiraffe]

Maybe you are using the right amount of fuel but not enough air giving the rich reading.....have you checked the air filter ?

That wouldn't be the right amount of fuel then would it...

 

[Mackerfly]

Was the engine fully warmed up before they tested the emissions?

 

[floppydog]

Hi Thanks for replys .

The air filter pipe to it is shot , but would that not work the othe way round in that lean ? Something is broke and telling the car that enginr need more fuel , could be a air leak .
the lamdba was running around 8v it has stored codes for a fault but the garage said it was working as when lowering the revs from high all was ok ... no other faults stored. the car was checked on 2 machine at diffrent garages and had ran for about a hour before test , all be it 15 to 20 at tick over .

 

[darrenclio172]

That wouldn't be the right amount of fuel then would it...

Dont you start.......

If the fuel injectors inject the right amount of fuel depending on load, temp, rpm etc and there is a restriction of air flow is that not going to give a rich mixture...... correct me if i am wrong.

You need to get the garage to check the live data

If you have a split pipe to the throttle body then ignore what i said unless it has an air mass meter (im not sure about the 1.2 engine)

 

[floppydog]

Hi and thanks I have had a quick look no mad and if I put my hand around that area I can feel a draft . Can tell at this point if its blowing or sucking (lol) should it do that ?

 

[floppydog]

Should be MAF ••••

 

[darrenclio172]

Hi and thanks I have had a quick look no mad and if I put my hand around that area I can feel a draft . Can tell at this point if its blowing or sucking (lol) should it do that ?

There should be a vacuum (sucking) at idle. The engine should only be able to suck the air directly from the air box, anywhere else is a leak.

 

[floppydog]

Hi and thanks , looks like a good place to start .

 

[ben lee]

if the engines running fine i.e no missfires. i would try replacing the coolent temp sensor and you will prob fine that running it rich has killed the cat.

 

[floppydog]

Thanks would this sensor make the co2 that high , as I understand without a cat they run at about 1%

 

[ben lee]

had some cars max out my machine before when running to rich.

 

[floppydog]

Thanks , every days a school day....