So I swapped O2 sensor on left bank and I immediately began to get O2 transitions whereas with the "old" sensor it would not get above .5v at idle.
It would show .8v and above in O/L and warmup. As it warmed up it would drop voltage. At cruise, it would get above .5v but still seemed lazier than the other bank. At idle it would generate a Left Lean O2 code. Now no code.
Along with installing a new O2, we re-routed the O2 harness as it was tie-wrapped to a SS hydraulic clutch line.
My suspicion is the way it was installed attenuated the signal. Or was it simply a defective sensor?

Thoughts?

 

Was it heated? I would tend to believe it was a bad sensor but o2's do strange things it seems. My ls1 would drop out of o2 switching sometimes and a tpi car i once tuned wouldnt register correct mv's vs wideband data. Heated o2's are necessary sometimes.

I dont know how susceptible the signal is to interfence from other sources/signals in engine bay. I never tried insulating the wires. And my 383 an turbo builds, i just skipped closed loop all together. Ran fine. Now goin ls1 ecm and trying dual o2's closed loop operation. We shall see

 

I'm not a EE, but IIRC I have read that due to the low O2 ECM signal voltage, having the sensor wires close to or resting on something like steel braiding would tend to "ground" or reduce the signal reaching the ECM despite the wire insulation. I'm asking the question to coonfirm my impression. I could have re-routed the wiring and tried that but frankly I only wanted to get under the car once and so went ahead w the sensor swap. Willing to accept that the sensor, which was new, was also defective. However, one of the diagnostic branches suggests a "grounding" issue w the O2 sensor.

 

I have found electrical noise in SS braided lines with an O scope! It was near a spark plug wire.

If you ever get a chance to run the suspected O2 sensor I'd like to know if this happened again?

FYI SS Braided lines do just as good a job of cutting through stuff as a file if there's any movement.

 

EM,

Chafing by the SS lines was another concern I had although the leads had a heavier sleeve around a section of them. The stock routing of the harness is to allow it to "float" away from either the block or exhaust. I have longtubes, so that changes the routing and in some cases requires putting a harness extension so as to reach the collector bung. On the left, the extension wasn't necessary.

 

Dom

I also have a z, a '91. What are you using to tune it, as I am preparing to buy a setup to do so. Thanks

 

Hi,

You on the Registry? I use TPRT w Moates Ostrich on G1 daughterboard, then I will do a final burn once its right onto a stock chip. Also using Zeitronix ZT-2 WB for WOT. Have fun.