Hi, Looking for some advice please regarding emmissions on my Mk5...took her for an M.O.T yesterday & only failures were a collapsed drivers side engine mount, 1 x split driveshaft boot & 3 x the allowed emmissions level...apparently if she'd been registered a day earlier it wouldn't have even been a requirement of the test (31/7/92)!! Just wondered if anyone else has encountered the same problem or can suggest any possible causes other than the cat...cash is a bit short at the moment so can't really afford trying one 1st!! - Thanks in advance.

 

What are the exact figures for the emissions test?
How much CO, HC, etc.

 

Yes, need to know the exact figures given, could be anything really, oil burning, over fueling, lambda sensor problem, failed cat, exhaust leak, inlet leak etc etc.

 

Sorry guy's have the test results to hand now...both failures are CO figures...Fast idle test is currently 0.88% & Second fast idle reading is 0.90%. Both results should be no more than 0.30% so there quite some way out at present, any suggestions would be much appreciated.

 

Without any other figures: defective catalyst.

 

CO isn't a cat issue. Nox and HC would be a cat issue. Service it, new plugs and filters inc fuel, oil etc put a tank of branded super in it, maybe some injector cleaning snake oil too. Thrash it about a bit to clear it all out and take it back for a retest red hot. It's basically it's running a tad rich (too much fuel), but only slightly, so not enough to send your HC over the limit, do you have any mods? The above is to try an increase combustion effiency to get that wee bit of spare fuel burnt and bring the co down.