M. Red WS6

I need some shooling on this subject, if anyone can help out I would appreciate you assistance!

What is the norm reading for sensor's in bank 1 at idle, cruising speeds and WOT?
What is the norm reading for sensor's in bank 2 at idle, crusing speeds and WOT?

If the sensors are out of the prefered range are they considered to be bad? How can I confirm that they are?

SSpdDmon

iTrader: (10)

The NBO2's (or HO2S's) should ocilate (sp?) above and below 450~550mV rapidly. They won't really bounce around as much in low airflow scenarios (i.e. idle or light throttle) and they will stop fluctuating during WOT (~900mV) and extended decel (~040mV). When looking at fuel trims, you ideally want them to be at or below 0%. Typically, there's a 2~3% difference between the 2 banks with the driver's side being the leaner of the two. If you're O2's aren't fluctuating very much, you're getting insufficient switching DTC's (diagnostic trouble codes), and there's a significant variance between the fuel trims from bank to bank, then I'd say you're looking at a bad O2. You can swith the left and right front O2's and see if any problems follow the potentially bad sensor. I believe that was my suggestion in your other thread....

M. Red WS6

Thanks for the input SSpdDmon!

If I follow what you said, then at idle the mV on all four sensors should be fluctuating between 450 and 550, give or take a few. If that is correct what does it mean when all four sensors fluctuate between 90 to 820, with occassional steady readings between 400 to 740? Does that mean that all four sensors are bad?

I did retrieve the following codes from the DTC notRan section from the Diablosport but the service light did not turn on:
P0125- Insufficient ECT for closed, loop fuel control
P0135- HO2s Heater Circuit Bank1 sensor1, Malfunction
P0141- HO2s Heater Circuit Bank1 sensor2, Malfunction
P0155- HO2s Heater Circuit Bank2 sensor1, Malfunction
P0161-HO2s Heater Circuit Bank2 sensor2, Malfunction
P0440- Evap Control System Malfunction
P0442- Evap control system (small leak), Leak detected
P0446- Evap Control System vent control circuit malfunction
P0704- Clutch Switch input circuit malfuction
P1441- Evap system flow during non-Purge
P1539- A/C high Pressure switch circuit high voltage
P1546 - A/C Clutch start circuit lo voltage

I believe that these codes came on after i disconnected all four O2 sensors, checked the resistance on C/D, reconnected them and took a test drive. To start the LTFT we around 7.03% in bank 1 and 8.59% in bank 2 for atleast 15 minutes before they jumped back up to 25% on both banks.

How bad can I damage my car if driven under these conditions until I get it fixed?

SSpdDmon

iTrader: (10)

They should be fluctuating above and below the mV's I originally listed. If your car is relatively stock (IIRC you said lid/catback), then I'd replace the front NBO2 sensors on both the driver and passenger side. There's no legitimate reason for the fuel trims to be maxing out at 25% on a relative stock car unless there's some kind of leak. When I say leak, I'm talking at some point after the MAF sensor and before the NBO2 sensors (ie intake, pcv, exhaust, etc.). Any unmetered air getting into the cylinders or any fresh air getting into the exhaust before the sensors will create a 'false' lean condition.

M. Red WS6

Thanks for putting up with a newbie SSpdDmon, I really appreciate your help!



I think I will try to look for that leak, I have inspected the EVAC system and did not find any leaks that I could hear or feel for.

I could not be doing this right, do you know of a more effective way of checking for leaks?