Hi,

I have a 99 classic turbo, which has just failed MOT on low speed emissions (7.5% CO, when it should be 0.5% max)

Car is also running really rough at idle, always trying to stall, and revs up & down.

All is fine when normal speeds (and abnormal speeds) are employed, seems just an idle problem, which makes me think Sensors, and closed loop fuelling etc!

Have replaced O2 sensor (Lamda) as this cured the similar problems I had before, but no luck this time.

PS all original cats in place, car is fully standard apart from Magnex back box and air filter.

Any ideas where to look next?

Cheers.

Foot2thefloor

 

hey mate,

i'm suffering similar problems but no where near as severe, thread below.

http://bbs.scoobynet.co.uk/showthread.php?t=469247

my '95 wrx failed CO emissions with readings at fast idle of 0.6% and 0.46%. 7.5% is right up there! It has been suggested that I replace my lambda sensor but no gaurantee that will fix the problem.

I understand that out of tune fuel injection systems can cause incorrect fuel mixtures and cause high emissions.

Does your Turbo have a cat? Perhaps it's cooked? A dose of unleaded can smoke your cat and lambda sensor fairly quickly.

What confuses me is that I've been told that my CO levels need to be below 0.3% but you've been told yours need to be above 0.5%. Perhaps it's because of the age difference of our cars? '99 vs '95?

paul

 

Hey Paul,

it a pain in the a-se, my problem is that at normal speed (fast idle) I an passing the emissions test, it is only at tick over there is a problem, I was told that the pass rate was 0.5% co or less at tick over, mine is pumping 7.5%.

I have both standard original cats still in place.

certainly a problem, from reading here I am thinking MAF sensor, but this is £77 which I would rather not spend unless I am sure!