ZR-1 Net Registry Forums - View Single Post - For tuners, a Holy Grail of Injector voltage Offset

XfireZ51 · 11-16-2013

While going thru this, I noticed on my datalogs that the O2 signal on the R/S would drop to 0v. Sometimes just a few frames, and other times I would get a whole string of 0s. Long enough and the ECM is going to react to what it thinks is a lean condition. The 0s appeared before I started playing around w the
Injector Bias, so I suspects something electrical. I checked the ECM connEctions and pins. Also tested the O2 signal and sensor ground for continuity. They checked out.
Ran a few more diagnostic tests after reinstalling O2 sensor ground line in ECM.

1. Unplugged A/C fuse to eliminate any possible "crosstalk" from the heater circuit. Both O2s remained at .45v after engine START.

2. Reinstalled fuse, disconnected O2 and jumpered the O2 signal to ground. Engine needs to be running otherwise it will always show the ECM bias value. This dropped the R/S O2 to .03v so that was good.

3. Tried both harness extensions I had. The one I made the other day appeared to be giving me a problem. So I made one more extension and installed it. Now its working w no signal loss altho the O2 will jump in and out of Closed Loop if CTS isn't above 77C. Fans kick on and drop coolant temps in this weather. Just need to get heat into motor. Hope to take it out tomorrow and do some logs
but looking at idle the O2 voltage seemed to be tracking closely along w INT. Right was needing to be somewhat richer than left as usual.

11-16-2013	#44
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,685	Re: For tuners, a Holy Grail of Injector voltage Offset While going thru this, I noticed on my datalogs that the O2 signal on the R/S would drop to 0v. Sometimes just a few frames, and other times I would get a whole string of 0s. Long enough and the ECM is going to react to what it thinks is a lean condition. The 0s appeared before I started playing around w the Injector Bias, so I suspects something electrical. I checked the ECM connEctions and pins. Also tested the O2 signal and sensor ground for continuity. They checked out. Ran a few more diagnostic tests after reinstalling O2 sensor ground line in ECM. 1. Unplugged A/C fuse to eliminate any possible "crosstalk" from the heater circuit. Both O2s remained at .45v after engine START. 2. Reinstalled fuse, disconnected O2 and jumpered the O2 signal to ground. Engine needs to be running otherwise it will always show the ECM bias value. This dropped the R/S O2 to .03v so that was good. 3. Tried both harness extensions I had. The one I made the other day appeared to be giving me a problem. So I made one more extension and installed it. Now its working w no signal loss altho the O2 will jump in and out of Closed Loop if CTS isn't above 77C. Fans kick on and drop coolant temps in this weather. Just need to get heat into motor. Hope to take it out tomorrow and do some logs but looking at idle the O2 voltage seemed to be tracking closely along w INT. Right was needing to be somewhat richer than left as usual.