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?

are you sure it isnt your AF's that are changing under load?



the o2 sensor generates electricity on it's own, it doenst depend on the cars electrical system other than for heating it if it's a 3 wire.

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?

have you tried moving to a better clean ground? also how and where did you splice into the output?

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.