Emissions - sorted

[Curran]

my car has now failed the MOT twice on emissions.

i have replaced the cat and lambda with no luck


its mainly failing on the CO levels. they are way to high particularly on idle. (8.88, limit is 0.5)

the HC is only slightly over on the first fast idle (209, limit is 200) but passed the second test.

the lambda reading was low on both tests at 0.94. it should be between 0.97 and 1.03


having read THIS THREAD (http://www.saxperience.com/forum/showthread.php?t=212713) a high CO and low Lambda points towards a faulty cat but mine is brand new so i assume its not that.

the guy at the test station advised i clean the throttle body and stick some redex in the tank and thrash the car on the way to the next MOT.

my old MOT has now expired so i can only drive to rebooked MOT's now which makes it harder to sort. the MOT station is just up the road and i really need to give it a good run on the motorway to benefit from the redex at all.


is there anything else i can do to get it through the emissions test?

i really need the car back on the road. i'm in the middle of my exams and i've got a job interview to get to which is a 100 mile round trip.

any help will be much appreciated.

also any guides to clean the throttle body would be handy.

[Curran]

any ideas?

[Curran]

i have now removed and cleaned the throttle body.

it was quite dirty with a fair bit of oil.

the was quite a lot of oil in the air intake coming from the breather. how much is normal and what is excessive? will this effect the emissions? and what should i do about it?

the inside of the inlet mainfold is also covered in a film of oil. do i need to clean this off? and whats the best way to do it?

i assume these things cant be helping the emissions. i would expect dry deposits to have a worse effect than oil though so i'm not sure?

[fossie]

When my old VTs failed its MOT i found that a service worked wonders as well

[Curran]

i gave it a full service at 67k, its now on 72k so it should be ok i think.

i'll keep it in mind though.

[Curran]

think i may have sorted it.

i found the air flow meter wasnt plugged in. the spark plugs where all sooty so i assume it was running rich but was unable to correct the fuel mix as it didnt know how much air was going in.

could this have caused the problem?

i have cleaned the whole intake system the best i can so hopefully it will pass this time. i'll find out tomorrow.

[fossie]

That being unplugged wont help (Dont think its the air flow meter tho, possibly MAP sensor)

[gouldy87]

any ideas?


yes, use a donor car

[Curran]

That being unplugged wont help (Dont think its the air flow meter tho, possibly MAP sensor)

it was certainly the flow meter. dont forget its on a mk4 golf, not a saxo.

i'll find out tomorrow if todays work has reduced the emissions at all.

yes, use a donor car

unfortunately i dont know a garage that would do that for me :(

[Jimmy-Boy]

mine was the same, fitted a new 02 sensor and it passed.

[Curran]

lambda / o2 are the same thing.

already fitted a new one.

[Mieran]

Could it be a faulty MAF?

[Curran]

possibly but i hope not. it was unplugged when it was tested. i've now plugged it in and have an emissions test booked for 3.30 so i'll find out if its made any difference.

if it doesnt pass then i'll have to pay for diagnostics. just wish i had done to start with rather than waisting £130 on a new cat and lambda sensor which seems to have had no effect at all.

[Curran]

its passed and now has a very low reading of CO at 2000 rpm of 0.0.

basically it all came down to the mass flow meter being unplugged.

the car does run smoother now that i've cleaned the intake and throttle body so i'm happy.