Espace IV Failing emission test - Lambda

[hawi15]

Hi - any advise on the following:
My Espace IV 2.0T failed emisson test with the following result:

CO 0,0 HC 004
CO 2500 0,0 LAMBDA 1,11

Idle speed a bit higher that normal.

Have been searching the forum and it seems to be various reasons for this kind of problem

Anyway I wasn't that pleased with the test as the engine wasn't warm enough (my opinion). It was -27C when sitting waiting and thus engine temp really low....

Is it worth doing a second test when the outside temp is higher?

BR
Håkan W

[roby37]

With a cool engine it would be more likely to show rich running. CO and HC are low and Lambda is also showing weak mixture. Have you checked for any exhaust leaks between the cat to the tail pipe?

[hawi15]

Hi ,
Thanks for the input - I've practically checked everything but I must admit that I haven't done a full check for leakage yet need to go to a garage with a proper lift....
BR
HåkanW

[hawi15]

Hi again,

Still failing - confusing results though

CO 0,9 HC 055
C02500 4,5 LAMBDA 1,42

The figures comes from the test report, but the guy doing the test said most values where fluctuating in a mannner he never seen before

Only thing done is replaced spark plugs and fixed a potential leakage of air after the filter...

No leakage found on the exhaust....


I must say that the most amazing thing is tghat the car actully is working very well. No indications of problems when using/driving the car.

Any ideas? Could it be "bad" fuel or something?

BR
HåkanW

[roby37]

I should have expected the weak running shown on the original results to be fixed when the intake leak was found. What, and exactly where was the leak?
Confusingly the CO is now showing rich running especially on the fast idle and a very weak mixture on Lambda to the extent that there must be doubt about it's accuracy.
It may be that the rich mixture is due to a faulty Lambda sensor and that on the original readings it was compensated for, by the intake air leak.
Not very helpful I'm afraid!