Contour Enthusiasts Group Archives Forums General Troubleshooting CO emission Failure

My '94 1.8 Mondeo (132K miles) has just failed the UK MOT Emissions Test due to too high a level of Carbon Monoxide at both "natural" idle and fast idle. I had a new CAT, plugs, leads, coil fitted two months ago.

Took it back and the first suggestion was some o-ring - replaced for $50 - no difference. The next thing they say they want to replace is the exhaust manifold gasket. Any suggestions how to avoid a long and expensive series of guesses.

Check the computer codes first. If you don;t know how to do this, it is easy, and descirbed in the Haynes manual. You just need a meter, no special equipment for your year.

Maybe the O2 sensor needs to be replaced? Is it original? If so, it's definently toast.

Brian

Well,

Check these pages

http://www.apcd.org/vet/failedveh.htm

http://www.txdps.state.tx.us/vi/publications/brochures/Failure_copy.htm

It gives a pretty good indication. Check the simple stuff like your air filter and your O2 (lambda sensor).

Originally, I was thinking a high CO was a lean mixture, but this
says it's probably too rich.

TB