I have been struggling with tuning my 350 tbi and i have ran wires straight from the ecu to the o2 sensor and and the o2 sensor ground, I hooked the ground wire up to a header bolt. I did this because I was constantly getting a reading of between .465 volts. I have a brand new o2 sensor and it is reading at 1.065 volts on my WINALDL. What could cause this?

 

If the O2 is reporting correctly it may be that the engine is running rich.

As a test, disconnect the wire from the O2 sensor and ground it to the O2 ground point. This should make WinALDL read close to 0 volts.

The O2 sensor ground to the ECM is important as it is the only reference for the O2 sensor amplifier in the ECM.

RBob.

 

I phrased that wrong, the o2 reading pegs to over 1 volt the second the key is turned on regardless of if the engine is running or not. I ran a new o2 ground from the ecu to a driver side header bolt. The car won't idle.

I will try your test tomorrow when my class gets out.

thanks

 

Ok, my temporary o2 ground wire melted on a header so that problem is solved, now to get the car actually running again.