Wiring An A/f Gauge
02-06-2004, 08:40 PM
#1
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My autometer a/f gauge gives really inconsistant readings. It seems like it is affected by the electrical load on the engine. It might say the engine is running a little rich at wot, but if i turn on the heater, headlights, and radio, it will drop 10 or 12 lights to extremely lean. If I turn them off, it goes back up. I originally attached the positive and negative wires behind the radio, but when it wasn't working i moved the ground wire to an engine ground on the frame. That helpped a little but the gauge still drops under load. Has anyone had this problem or know how to fix it?
02-07-2004, 04:36 PM
#3
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no, my engine would have blown up already if it was running as lean as it says it is. I have tried turning things off and on under full throttle and there is no difference in performance.
I know that the o2 sensor generates its own voltage but the a/f gauge is just a voltmeter. it compares two voltages, the o2 voltage to the ground voltage, which should be 0v. Since the o2 voltage should not be affected by electrical load i assumed that the ground was not truly 0 volts, somehow it is being polluted by other electronics. i don't know enough about electricity to explain how this could happen but I don't know of any other way the readings would be getting screwed up. anone have any ideas?
I know that the o2 sensor generates its own voltage but the a/f gauge is just a voltmeter. it compares two voltages, the o2 voltage to the ground voltage, which should be 0v. Since the o2 voltage should not be affected by electrical load i assumed that the ground was not truly 0 volts, somehow it is being polluted by other electronics. i don't know enough about electricity to explain how this could happen but I don't know of any other way the readings would be getting screwed up. anone have any ideas?
02-07-2004, 09:03 PM
#5
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it was originally grounded to the negative battery terminal but since it wasn't working i moved it to the ground on the frame right below the vin. that seemed to help a little bit. what do you mean by a clean ground? I hooked up the output for the o2 sensor to the wire coming out of the top. I ran it through the firewall and attached it inside the engine compartment as opposed to hooking it up to the ecu input inside the car.
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