For some reason while data logging im seeing -15.4 psi never varies. Factory gauge on dash is working properly 30psi warmed up and increases with rpm. Im sure its probably something with hp tuners . Brand new gm sending unit if it matters.

 

You can't log it through the PCM on these cars. I know it will let you select it, but did doesn't actually do anything.

 

There's no sensor hooked up to the PCM from the factory. I went through the same disappointment with my C5. The annoying thing is that car has the sensor, but it's only wired to the dash.

 

Well damn. Thanks for the replies .

 

Since my EGR is deleted, what I ended up doing was add a 5v 0-100psi sensor below the factory OPSU, and logging it through the EGR signal wire like some do with a WB02.

 

I have been doing that for fuel pressure.

 

So what is the voltage signal I am seeing on OBDXplorer? It goes up with RPM...