BRB_85.5_NA

Probable diagnosis and fixes?

Thanks,
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" /> B

bavarian banshee

you dont mention if you failed at idle or under load.
as a general rule, co is a good indication of the combustion efficieny of an engine. to be simple, its the product of incomplete combustion. in a perfect world (read, math book) the products of cumbustion shoud be co2 and h20. what happens, when the engine is lean, there is not enough oxygen for the fuel to completly oxidise the way it should, and turn in to co2. thus, we have just co. since you didnt fail on hc (unburned fuel) im going to go out on a limb and say its nothing too major. the first place i would check are things that would restrict fuel, or allow too much air. it may be as simple as a plugged fuel filter, or a vacuum leak. anything that would throw off the mixture. i'll bet good money that your o2 sensor is ok, otherwise you would have failed hc as well. the engine defaults to a rich condition to protect itself if the o2 sensor fails.

anyways, dont be too concerned, and start with the simple things. they are most often the culprit. most of it you can do yourself if you have the time, like looking for a vacuum leak, and changing the fuel filter.

hope this helps
take care

brian

Mark Parker

As a rule of thumb, excess CO is a result of too rich a fuel mixture, you're getting more fuel than you need, or not as much air. Clogged air filter, high fuel pressure, leaking injector, lazy or defective O2 sensor, improper input by the coolant temp sensor, or even a bad thermostat not allowing the engine to come up to operating temperature. HC failures are caused by incomplete combustion, not burning all the fuel you get. A misfire for any reason will cause high HC. The combination of HC and CO in excess would likely be the result of a gross oversupply of fuel.

bpp944

I went through the very same thing not so long ago.
I changed my oil, used "CRC Garunteed to Pass" fuel additive, following the directions. I ran the car real hot and took it in to be inspected. The car failed. I ran another tank of the "CRC magic juice" and it passed with flying colors.

led

fix? move to PR! my car got tested and passed without moving an inch from my house... you figure it out <img border="0" title="" alt="[Wink]" src="wink.gif" />