Datamaster says both my O2s mv are staying around 460-470. I don't know how to interpret Datamaster logs, pretty much all I can do is search around for acceptable and unacceptable readings and go from there. After looking around it seems like a normal functioning O2mv should oscillate between 100-900 quickly? If it is staying around 450 this means that the O2s are not warm enough to function yet or they are bad. Or did I misunderstand?

This reading is well after it should have entered closed loop and the O2s were warm. Do I need to replace my O2s? Thanks

 

Could indicate an open circuit, due to a wiring problem, or an O2 that has an open circuit. What you may be seeing is the 450mV bias voltage supplied by the PCM. As the sensor heats up above 622*F, the thimble in the sensor adds to or subtracts from that voltage, depending on the O2 content of the exhaust.

But, if the O2 sensor reading stays between 350mV - 550mV for 60 seconds, when the engine has been operating for more than 2 minutes, coolant is above 158*F, the throttle is more than 5% open, and DTC 21 and DTC 22 (TPS errors) are not set, it should be setting DTC 13 for the Bank 1 sensor and DTC 63 for the Bank 2 sensor being open circuit.

Another possible cause of this problem is the outside of the O2 sensor being cut off from a fresh air supply, due to contamination, a coating of oil or coolant, or damaged sensor wires.

Does DataMaster indicate any codes?

 

3 codes were shown. 26, 77 (fuse keeps blowing. Going to look at that issue soon), and 33. With the DTC 33 I thought I addressed that issue a few weeks ago. MAP kPa was over 80, replaced spark plugs and now its down to normal) Need to reset the PCM to get rid of the DTC 33?

 

Reset and see if any codes come back. Pull "PCM BAT" fuse in end of dash panel for 30-seconds.

DTC 26 = EVAP purge solenoid electrical circuit. Same fuse as the cooling fan relays. See below.

DTC 33 = MAP sensor high voltage/low vacuum. Bad plugs would have to be virtually destroyed to cause the MAP to exceed 80kPa at idle. Did you check the condition of the MAP sensor harness connector? They dry out and crumble, producing erratic readings.

DTC 77 = Cooling fan relay #1 (or primary). Is it #6 under hood fuse? Do you have a 10 amp fuse in the circuit? Have you checked the relay, to see what is causing the fuse to blow? There are several other items powered off this fuse - have you checked them? EVAP purge solenoid, EGR solenoid, low coolant relay, reverse lockout solenoid (manual trans, but you don't have a signature, so we have no idea what kind of trans you have).

Add a "Signature" with basic info about your car - year, model, engine, trans and any major mods. The more info you provide up front, the better help you will get.

 

The same time I replaced the plugs I also adjusted the TB set screw and TPS to get the IAC counts down from 160. I don't know if that would have helped get the MAP kPa back to normal. Haven't had any issues with the MAP kPa since. I'll reset PCM though and see if it goes away.
As far as the O2s since I didn't get DTC 13 or 63, is it narrowed down to either the reference air being clogged or bad O2s?

 

....or the wires are not connected, or not making good contact.

 

Well I'm at a loss. Swapped with different O2s and is still reading the same. All wires from harness and extensions are good...

 

How did you determine wires and harness are "good"?

Are you sure fuse #6 is OK? That also powers the heaters in the O2 sensors.

 

Well an update for now. Haven't had a fuse in 6 for awhile now since it kept blowing them. After you said it is also for the O2 heater (which I didn't know) I put a new one back in there to try and address the DTC 77 and see if that fixes the O2 problem as well. Fuse didn't blow and had no SES light. Would the !EGR have been what fixed this problem? Anyway thats the update as of now. I'll run data master in a bit and see what the O2s are reading now.