I'm having issues with my car going into closed loop. the car is a slightly modified, all motor GSR integra, but I imagine that Open Loop vs. Closed loop would basically be the same for any car, or at least any Honda. I originally thought the issue was a faulty O2 sensor, so i swapped out the sensor and while it does run much better, it is still stuck in open loop. I'm finding that is stuck in open loop via a cheap obd2 scanner. I tested the TPS sensor and it is just barely out of spec during WOT, but it is consistent with no dead spots as you rotate the throttle. I'm thinking my coolant temp sensor is fine because it is reading correctly on the scanner. Last night, i tested voltage at the ECU to verify signals sent to the primary O2 sensor. This checked out good, so tonight or tomorrow night I will check for voltage at the sensor to make sure there is not a break in the wiring somewhere. I did see the car go briefly into closed loop, but the car idled at something like 500 rpm and struggled to stay running. After about 3 seconds or so, it went back to open loop and began to run fine. There is also no CEL present at all or pending CELs.

My main question is: what all sensors / factors determine when a car should go into closed loop? If i get some more information, it will hopefully point me in the right direction for other items to troubleshoot.

 

What management are you running?