Question on O2 sensor placement

**lionelhutz** · 09-22-2016

Sorry, D6 is the negative for your ECU.

**BlueCorvette** · 09-22-2016

I misunderstood the wiring, it has two heater, a sensor, and a ground.

I'm testing it out now. Oddly, my car did not report going into closed loop, like it had before. My data logging seemed to be working. Is there a condition that forces it to open loop at idle, after the loop control start timers expire?

I am seeing voltage start at .450 and then go to .5 to .6, but my wide band is showing slightly lean. Not sure what that means. Getting crossover counts also. Can someone explain what those are? Is that just when the voltage is going from lean to rich and back?

**lionelhutz** · 09-22-2016

The 2 heater wires go to power and ground, they are both the same color and it doesn't matter which way. The sensor has a signal and ground, you tie the signal to the original O2 wire and the ground to the tan wire on the rear intake bolt.

Not sure if that's what you meant by 2 heater wires or if you meant you're powering both heater wires.

Crossover counts should be when it goes rich to lean.

**BlueCorvette** · 09-22-2016

Originally Posted by lionelhutz

The 2 heater wires go to power and ground, they are both the same color and it doesn't matter which way. The sensor has a signal and ground, you tie the signal to the original O2 wire and the ground to the tan wire on the rear intake bolt.

Not sure if that's what you meant by 2 heater wires or if you meant you're powering both heater wires.

Crossover counts should be when it goes rich to lean.

Thanks, yes you are right about the wiring. The bosch came with this stupid no text pictogram for the wiring. I had both white wires powered, so it wasn't powering the heater.

**BlueCorvette** · 09-23-2016

I think I have it working. That 12v transmission sw connector was a bad idea, not a good power source.

I'm a novice at this, and I have never had a good o2 sensor to datalog, so I was completely on the dark as to what that looked like.

I can now see the crossover counts cycling, and the o2 reading flips back and forth from less than .3 to greater than .7, along with the rich/lean indicator. So it seems to work great.

Odd thing is, I have a minimum open to closed loop delay timer for a hot engine of 100 secs. I'm pretty sure the ECU commanded closed loop after less than 30 secs. I had been using the hot/warm/cold delay timers set to 8.5 min to force open loop, so I could adjust the MAF tables there.

Thanks everyone.