O2 Sensor CELs with Headers

I know this has been discussed (I have searched and reviewed), but I not really seen any definitive solutions.

2005 4.7 with Dirty Deeds long tubes, full custom 2-1 non-race system, maintain stock cats, extended upstream O2 sensor harnesses, everything else stock.

Immediately popped 2441 (SAIS) and 2241 (pass. side upstream O2 circuit low), not really any surprise there. I drove it for awhile since I was busy, but finally had time to get the Rutech kit which was a breeze and promptly solved the 2441.

However, now in addition to the 2241 (which didn't magically go away, bummer), I also have a 2238 (same thing driver side).

While I was putting in the Rutech kit I also added an O2 spacer on the passenger side (this one - https://jcarpart.com/products/obd2-...pacer-kit-generic?_pos=1&_sid=5eea7c470&_ss=r )

The 2241 did not go away, but I also have not tried adding any of the reducer bushings that came with the kit. I went ahead and ordered a second one to add to the driver side so I can start playing around with the reducers on both.

My questions: if the spacers don't solve the problem, any other ideas? The extended wire looms are good, no exposed or broken wires. I'm thinking about ordering whole new O2 sensors with the factory wiring through Toyota since I have a sneaking suspicion the way that the 90 degree spacer is configured, if I remove the engine-side plug from its hanger, the stock wiring might fit without having to cut and splice? Maybe....not sure, I haven't measured but I also don't know how long the factory wires are.

Secondly, and one that's been nagging me, is it detrimental to my long-term motor health if I'm "tricking" the computer into thinking the A/F ratio is good by pulling the O2 sensor back? Yes, I do want to get rid of the nagging codes, but I also don't want to run too rich or lean and blow out a cat or worse.

Any help is appreciated!

 

This was the first giveaway. I believe there is an issue here. Below is just some basic info for anyone reading this and for future searches.

DTC P2241 causes
Faulty Air/Fuel Sensor Bank 2
Air/Fuel Sensor Bank 2 harness is open or shorted
Air/Fuel Sensor Bank 2 circuit poor electrical connection
Air/Fuel Sensor Relay
Faulty Engine Control Module (ECM)

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

The Air-Fuel ratio (A/F) sensor provides output voltage approximately equal to the existing air-fuel ratio. The A/F sensor output voltage is used to provide feedback for the Engine Control Module (ECM) to control the air-fuel ratio. With the A/F sensor output, the ECM can determine deviation from the stoichiometric air-fuel ratio and control proper injection time. If the A/F sensor is malfunctioning, the ECM is unable to accurately control air-fuel ratio. The A/F sensor is equipped with a heater which heats the zirconia element. The heater is also controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is low), current flows to the heater which heats the sensor to facilitate detection of accurate oxygen concentration. The A/F sensor is a planar type. Compared to a conventional type, the sensor and heater portions are narrower. Because the heat of the heater is conducted through the alumina to zirconia (of the sensor portion), sensor activation is accelerated. The code is output when there is an open or short in the A/F sensor circuit, or if A/F sensor output drops. To detect these problems, the voltage of the A/F sensor is monitored when turning the ignition switch to the ON position, and the admittance (admittance is an electrical term that indicates the ease of flow of current) is checked while driving. If the voltage of the A/F sensor is between 0.6 V and 4.5 V, it is considered normal. If the voltage is outside of the specified range, or the admittance is less than the standard value, the ECM will determine that there is a malfunction in the A/F sensor. If the same malfunction is detected in the next driving cycle, the MIL is illuminated and a DTC is set.

 

I've opened up the loom (after it was lengthened) and all connections look good, soldered. So can you lose voltage simply by making it a few inches longer?

Additionally, I cleared the codes for giggles and made my 2 and a half hour commute home, and they never came back on (I'm sure they will eventually), but the truck is now not running great. Pretty rough idle. Maybe I yank the spacer and live with the CEL's and a smoother running truck?

Additionally (again), I have tried and failed to find a local tuner to tackle this since it is not my area of expertise. A lot of guys won't touch it because of EPA stuff. I'm not necessarily looking to add performance, I just want to get the A/F right, the motor running healthy for longevity, and the CEL's gone. Is that too much to ask?

 

Are you still running it with the extended harness?
So because you cleared the ECM, the truck runs like crap because it’s going through a relearn procedure. If you didn’t, disconnect the negative battery cable, perform and PROPER throttle body cleaning (THIS IS IMPORTANT), then reattach the cable and perform a drive cycle. See how it operates after that.

 

You can expect the ECM to throw P0420/P0430 Codes (Catalyst System Efficiency Below Threshold) eventually with headers on the 1st Gens (my experience and many others) but these codes you are getting are not typical if the all the work was done properly. I agree with Black Snek that it's probably in the extended wiring but I also wouldn't think the upstream sensors can measure the exhaust gases effectively when spaced that far away. That can certainly affect performance, unlike the downstream sensors which are only there to monitor whether or not the cats are working properly.

 

My guy at Toyota thinks perhaps the sensors themselves are bad? I find it weird that now both sides are coding. I think the rough idle is working itself out, just seemed to take longer than normal for the computer to relearn. But now the codes are back which means I'm back to square one. I might ditch the spacer and look for another option since the truck seemed to really not like that, and I don't love the idea of the A/F sensor not being able to get any accurate reading. You're right on the downstreams, I would be less worried about those for the reason you mentioned.