I have an Acura legend (1995) that I did a header swap on and replaced the o2 sensors. They aren’t connected as of now and the car is running rich because of it. If I wanted to trick the car into burning less fuel with the o2 sensors disconnected, how much voltage would I need to put into the wire leading back to the ecu from the sensor wire in the harness(assuming I differentiated it from the heater wires already).

P.S just disregard the fact that I unplugged it and whatever it was just to setup a situation, just how much voltage should I put back into that wire?

  • Car is presumably running rich because its get close to 0 from upstream sensor, so it thinks a too much air too fuel, so add fuel. Assume your trims are up. In theory what you want is to reset the trim, and then return exactly .45V. The ECU should treat that as perfect balance and keep the trim settings the same.
    – Chris
    Oct 23, 2017 at 23:08
  • 1
    I take it the reason the O2 sensor isn't connected is because the harness won't reach it at it's new location? If so, why not just extend the harness and make it right? It only takes a little bit of time, wire, solder, and heatshrink to make it happen. Would save you a bunch of time and energy (yah, petrol energy, if you get my drift). Oct 23, 2017 at 23:20
  • how about an o2 simulator? those used to be a thing iirc.
    – Ben
    Oct 23, 2017 at 23:27
  • The thing is my dad did a header swap, and he just put some random things in the o2 sensor holes to plug it up I guess, so there’s no harness coming out of them at all to even extend!! That’s why I wanted to just feed the car a low voltage reading on that o2 wire so when it does run rich it doesn’t eat up all my gas, it just runs... less rich if that makes sense lol. I just need to know how much voltage range to feed that sensor wire to trick the ecu into thinking theres a sensor there at least Oct 24, 2017 at 1:38


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