View Full Version : o2 sensor and autometer air/fuel gauge

08-09-2002, 03:54 AM
Ok well i hooked up an autometer air/fuel gauge tonight. Before i did this i checked my o2 sensor to see if it was working. The main red wire was getting a 12.6V reading which is normal from what i know. Well the white wire was reading .06V at idle. Even when i rev'd it up at idle it would only jump a little maybe .02V at the most. The air/fuel gauge stays pegged at lean and doesnt move. At idle the light is so dim you cant even see it. I plan on getting the greddy setup within a few days but this doesnt seem right that its reading lean like that. every since i installed it my car almost dies when i come to a stop. Also i installed an autometer boost gauge. While driving it reads like 20 vac and then when the turbo spools it moves to where it should right around 7.5 pounds. But i dont know why it reads a vacuum when not boosting. anyone had this problem? The boost line is straight from the stock boost line right off the throttle body. Any help appreciated.

08-09-2002, 01:27 PM
when your not at boost you will get a Vacuum reading...boost gauges measure the manifold pressure, if you car is NA it will always read inches Hg...think about it, your head is sucking in all the air from the manifold, therefore making Vacuum, when you have forced induction the manifold pressure is the amount of pressure that your engine CANNOT use, or suck in, therefore reads a PSI reading from your manifold, as the pressure is "backed-up" ...so your boost gauge is fine...the a/f usually isnt very active at idle, but if you are running around and boosting all the time and it NEVER leaves the LEAN portion of the gauge, something may be wrong.