How to test for closed loop?

[baldguy]

I think my procharged '98 might not be going into closed loop strategy. The reason I think this is that my OBD2 reader never seems to be able to read from all of the O2 sensors - only half (the front two, I presume). Their documentation says that once the closed loop strategy engages, all O2 sensors will become available for sampling. Of course this could be bad O2 sensors, but I'm not getting any codes...

Any idea how to test/verify this? Any symptoms of a car that is in that situation? What might be causing it if it is indeed happening?

 

[ZeroDCX]

I assume you mean that you're able to read from the upstream sensors but not downstream? Are you sure that your tuner did not turn the downstream sensors off with the tune? If they have, the downstream sensors will read constantly at 0.0V. This is a non-issue as they're not important outside of diagnosing catalyst efficiency/lean/rich condition issues.

B1S1 and B2S1 = Upstream A/F ratio Sensors (the important ones)
B1S2 and B2S2 = Downstream Catalyst Efficiency Sensors

Also with an OBD2 scan tool there is a PID which indicates current "Fuel System Status" (open/closed loop). I'm not sure of specifics off of the top of my head, but will report back after finding out. Assuming someone does not post the accurate information prior.

 

[baldguy]

I'm not sure of that, to be honest. The car was tuned before I bought it. it's nice to have so much already done (and to my liking) but it's kinda strange not being there for the mods, heh.

Thanks for the info. I'll check those PIDs and see what I can figure out.