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Not necessarily. Sorry Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Mon, 19 Apr 2004 13:12:09
In Reply to: O2 fault confirmation, Evil Twin Skippy, Mon, 19 Apr 2004 12:40:09 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I wish it were that simple. Alas, it is not.
A very low voltage indicates a bad O2 sensor OR lean mixture. The O2 sensor runs over a very narrow range- it doesn't take much of a lean (or rich) mixture to 'peg' the sensor. If you've got a lean mixture, the O2 sensor can very well be telling the truth, replacing it will do no good. One way to get a lean mixture is to have a vacuum leak, and one symptom of a vacuum leak is a fluctuating idle.
I'd start checking for vacuum leaks. If you want to get a better feeling on the O2 sensor, pull the vacuum hose from the Fuel Pressure Regulator and plug it. See if the O2 sensor voltage changes - it may swing all the way up to 0.8 and stick. Why does that work? The FPR changes the fuel pressure as a function of intake vacuum - less fuel at high vacuum (typical at idle), more fuel pressure at less vacuum, or even pressure (turbo boost). If you open the FPR to atmospheric pressure, it'll richen the mixture up a lot - possibly enough to overcome whatever is causing the lean running.
posted by 192.249....
, Mon, 19 Apr 2004 13:12:09 <-- Viewing This Message
, Mon, 19 Apr 2004 12:50:19
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