cygnusx1 Posted September 21, 2004 Share Posted September 21, 2004 Can anyone tell me what voltage they get from the O2 lead to ground with a full warmed engine idling? Using factory Turbo ECCS and O2 sensor. Also does the voltage read steady or does it swing around every two seconds or so? I can get steady 0.8v at idle and 2500rpms with no ECU LED flashing and no voltage swing. However, if I tune the AFM to try to get 0.5v it starts to drift voltage from 0.3v - 0.6v in about two second intervals almost simultaneous with the green LED flashing on the ECU. Is it Normal for the voltage to swing like that and the LED to flash at IDLE and at CRUISE? The TPS is working and set correctly. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted September 21, 2004 Share Posted September 21, 2004 IIRC, and that's a big if in this case because I'm no FI expert, the voltage dancing around is the system going in and out of closed loop. Totally normal. Normally I wouldn't post on something I know so little about, but I remember when my buddy was tuning his turbo Toyota truck it was doing the same thing and we talked about it. Sounds like you've got it tuned pretty good to me. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted September 21, 2004 Author Share Posted September 21, 2004 OK Cool! I think my Z is finally happily idling and cruising in closed loop. I now believe that the green LED on the ECU indicates that the O2 sensor and ECU are "cross counting". Read below. QUOTED FROM : http://www.therangerstation.com/tech_library/O2Sensors.htm ......"In order to read the O2 sensor, most computers send out a certain voltage to the output terminal of the sensor. This is typically around 450 millivolts. Since we know that the sensor sends low voltage (under 300mv) when a lean condition is present and a high voltage (over 600mv) when a rich condition is present, the computer can count the number of times the sensor crosses the 450mv mark. Cross-counts are the number of times an O2 sensor crosses 450mv. A scanner can "look" at this for you. Even though you can't see the number of cross-counts without a scanner, you can use a digital voltmeter to watch the open/closed loop system operate. Just connect your meter as Illustrated above, while the O2 sensor is still connected, and start-up the car." EVEN MORE: http://hostingprod.com/@aa1car.com/library/o2sensor.htm Quote Link to comment Share on other sites More sharing options...
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