I have a new gauge that is not agreeing with TunerStudio, and I believe TunerStudio seems to be more correct, but I want to know how and why.
I have a 1984 Nissan 300zx NA2Turbo with MS3X full sequential installed. Here is a rundown of the parts I am having a little bit of trouble with:
- Innovate LC-2 Wideband controller with a new sensor that is about 20" behind the turbo
- MS3X grounded to the firewall right next to the stock battery ground strap (using an old tie-down threaded screw hole)
- Innovate G5 Analog AFR gauge
All of the above components are grounded to the same place, and they all get their 12V+ source from the same IGN wire. I have the EGO wire connected to the LC-2 yellow wire, and the AFR calibration is set to LC-1/LC-2 Default. The same yellow wire is connected to the sensor input for the gauge. Even if I set TunerStudio to 0V = 7.35 and 5V = 22.39 the value being read in stays the same. Of course, that is the value that is included in both the LC-2 and G5 manuals.
So my question is: If TunerStudio and the G5 are getting the same IGN, GND, and SIG from the LC-2, and they are theoretically calibrated for the same linear response signal, how could their readings be off? I mean, I can set idle to about 14 or 14.5 in TunerStudio and the engine is fine with it. At that point, the gauge will read around 12 or 12.5. If I try to lean out idle so the gauge reads 14.5, the engines slows a bit and Tunerstudio reads around 16.5.
Does the gauge reference the "always on" 12V+ source in its readings? That is the only wire that is not shared between MS3 and the gauge, and I know I have some small grounding issues with some interior electronics (hence why I grounded the ECU to a fresh ground next to the battery strap). I am going to replace my battery ground so that may help, but I didn't think the gauge would even care if voltage fluctuated a little bit on that wire.