Can anyone suggest a cause for these MOT fail lambda readings (greater than
1.030)?Fast idle test: 1.066 Second fast idle test 1.180
The car is making an annoying rattle (like pinking in the old days), which someone suggested may be that cat falling apart after a bump, but maybe it could also be actual pinking caused by whatever caused the above readings. My (albeit cheap) OBD reader isn't showing any codes, and the management light isn't on.
is it a 1300 or a 1.25? rattle is usually a broken up cat (which would be less effective than a good cat). 1300 suffered from dodgy connections on the ect sensor which made them run poorly. usual cure was a new sensor and a clean up of the plug. other than that, has it been properly serviced and taken for a good blast? high lambda with other stuff about right can be caused by a minor exhaust leak. So investigate the rattle would be a good start and check for leaks at the same time.
It's a 2003 1.4 Zetec. I bit the bullet, and took it to a dealer. All they've done is replace the crankcase ventilation valve, and the rubber tube; and done some kind of PCM update. They say it now passes their emissions test. I can sort of imagine there being a connection between oil mist and emissions readings, but I'll only really believe it's fixed when I take it back for the retest (there's no way I'd actually take it to the dealers for an MOT, but I'm happy to let them fix something I can't). I don't know if they'd have spotted a broken up cat, since it's a pig to get at.
MOT bloke said there was a tiny leak at the backbox (I take it to the local ATS - it only costs 30, and they always pass it, until this year with the emissions problem), but that it wasn't significant.
The rattle is still there, though.
I would stick some gun gum in the hole first.
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