Question:
Why would someone install a catless offroad x pipe with long tubes... And have rear 02 sensors? And they are wideband. I didn't even notice them til a few days go. Feel like an idiot. If the downstreams are being pummeled by exhaust that isn't passing through a catalytic converter, would that leave the potential for them to tell the computer to adjust fuel trims?
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The car came from California. Maybe it was flashed before I bought it? S&B also "claims" you don't need a tune for the CAI that is on the car.
But again, with the FRPP intake manifold, 62mm tb, XFI cams, long tubes and catless x pipe with a total of four O2 sensors on the car, wouldn't it throw a bunch of codes if it was flashed and driven? Would it even start?
Ok, now the pieces are coming together. 1st off, the O2 sensor w\ the green sleeve & green connector is actually a NB sensor--not a WB sensor. This green connected O2 sensor is actually a pre-cat NTK 22060 O2 sensor (these used to be Ford OEM pre-cat NB O2 sensor from 1996 thru 2010 MY of S197 production....WB O2 sensors didn't show up on Mustangs until MY 2011 w\ the advent of the Coyote V8) & it should not have been placed there---it is designed
for engine feedback control only. The blue connector NB O2 sensor is actually a post-cat NTK 22500 O2 sensor (same as listed in parenthesis above) which are designed to check for the existence of free O2 in exhaust
post-cat or mid bed of the OEM cat only....not used for engine feedback control. The element shielding is not the same size thus they use a different sampling size so if these are mixed up as your picture is showing (assuming the same install scenario in the LTH's prior replacement) then yes, the O2 sensor feedback to the engine bank that the blue connected O2 sensor was installed would indeed have been skewed so engine fueling on same bank would also have been skewed. Needs to be fixed.....put the other blue connected O2 sensor in place of the green O2 sensor in the midpipe then install both new NTK 22060 pre-cat NB O2 sensors in the LTH's to rectify this mess. Only the O2 sensors plugged into the green harness connectors (you most likely have O2 sensor extensions plugged into these in order to reach the O2 sensors installed in the LTH's)
provide feedback to adjust fuel trims, O2 sensors plugged into the blue harness connectors only check cats &
don't have anything to do w\ fuel trim adjustment at all. I would suggest that you make sure that all these are connected properly to the proper harness connectors as laid out here.
Now as for your other question, this was the status quo that folks did to these cars due to past issues w\ cats
back in the day being "flow restrictive" thus power robbing (race car\performance thinking) so SOP was to go w\ an O\R midpipe (no cats) when installing LTH's. The tune was definately flashed before you bought it (among making O2 sensor transport delay setting changes for the full length BBK LTH's, disabling the CMCV's for the FRPP IM, maybe some ETC smoothing for the FRPP 62mm TB & some tuning for the Comp Cams 127200 cams...the rear O2 sensors are most likely also disabled in the tune thus no DTC's for them). This was done in Cali as well also back in the day.... The rear O2 sensors, while not enabled in the tune, do still need to be plugged into the harness as the PCM needs to see the O2 sensor heater 12v+ voltage as well as some sensor output voltage thru them in order to not fail all the O2 sensors. So as long as you've registered your car in a county that doesn't require a smog test passage to get your registration you can leave the midpipe as is.....at this time I should say & leave it at that. If S&B claims that the CAI doesn't need a tune (MAF transfer function change in tune to align MAF airmass values according to the ID of the MAF section in CAI) then you really need to get this car retuned after you fix\straighten out all the other broke stuff.....once you get all the O2 sensor mismatch straightened out & EVAP CPV replaced I would then run datalog again on a full cold start & record all until car reaches full hot idle to see if the MAF readings still follow an inverted pattern (low gms\sec on high RPM's then gms\sec increases as engine warms up & drops RPM's)....if they still do this then get a retune....preferrably from someone like Lito....as this was most likely messed with in the tune after you verify all MAF wiring\voltages are within spec & you've replaced the current MAF sensor w\ an OEM MotorCraft ALFM-131 MAF sensor for your MY Stang (which according to your prior posts you've already done?).
Probably should have mentioned I unplugged my EVAP purge valve's power and then the line going to the canister. Put my finger on the purge valve inlet stem and it was still pulling vacuum.
So if it is stuck open, seems like it would be pulling fumes/air into the intake manifold and creating a lean environment no? I also pulled the purge valve hose connected to the intake manifold and plugged the intake with my finger. Seemed to run a lot better for that moment.
I'll have a new purge valve on tomorrow morning.
Now you know why I made this suggestion in my posting......this is 1 of the most overlooked parts of these cars....outside of the gas cap. Yes if these CPV's are stuck open\seat failed you
will pull in excessive unmetered air along w\ the canister fumes & create a "vacuum leak" due to drawing air in thru the canister after the canister has no more fuel vapors to add to the air. You also need to test the
flex line that connects the EVAP canister to the CPV line at the canister for cracks as well at a minimum....thus why I suggested to do a smoke test on the entire induction system. I'm surprised you haven't gotten any EVAP DTC's as w\ that stuck open CPV the EVAP canister\system can't be tested by the PCM so this is also suspect IMHO. These parts can fail & not immediately set a MIL so it is important to physically check these for proper operation....and especially whenever you suspect a vacuum leak!
These S197's are getting old enough that all this stuff needs to be gone thru to ensure that all is working properly. I would also suggest that the EVAP canister CVS should also be replaced as well (this valve is used by the PCM to perform EVAP system leak tests)...it is NO (normally open when no power is applied to it) whereas the CPV is NC (normally closed when no power is applied to it)....the CVS seats usually go bad meaning they will work but not fully seat off thus not allow the system to have a vacuum pulled on it when the PCM is trying to run EVAP leakdown tests.
Hope this helps.