O2 Delete and SAI Delete but getting Error Codes. Picture of codes Inside.

[Arsenal2012]

So I deleted the SAI and O2 sensors last November and as soon as I did that I got a CEL on.
Here is the thing I also got a ECU tune so I figured it was an unplugged sensor somewhere but did not worry about it then...

Well now I have to get emissions and I go to Autozone to read the codes and this is what they read.

It looks like its all O2 and SAI related, was the Tune not done right? The tune was from VAG Autowerks

[glennda5id]

Which O2 sensors did you unplug. Those codes are for the upstream sensors which are needed. You should be unplugging the downstream (post cat) sensors. The other code isn't related to the SAI.

[Arsenal2012]

Which O2 sensors did you unplug. Those codes are for the upstream sensors which are needed. You should be unplugging the downstream (post cat) sensors. The other code isn't related to the SAI.

The O2s are Precat(upstream), I also removed the Combi Valves and the SAI.
The ECU tune should have set precat(upstream) to ready state as was specified would be done, so I am guessing the tune was not done correctly?

What is the Tank ventilation valve open associated to then if it is not the SAI?

[glennda5id]

Your tune is running without upstream sensors, but you left in your down stream sensors?

[Arsenal2012]

Your tune is running without upstream sensors, but you left in your down stream sensors?

Technically they should have all been tuned out and the downstream sensors were just left in. Why?


What is the Tank ventilation valve open associated to then if it is not the SAI?

[rollerton]

Technically they should have all been tuned out and the downstream sensors were just left in. Why?


What is the Tank ventilation valve open associated to then if it is not the SAI?

Tank Ventilation is the EVAP system, includes the little N80 valve by the airbox, plastic hoses to the tank, the stupid pump and valve etc...

What car/ engine is it? Technically ...some of the more smarter people have said that the 02 sensors, at least downstream?, shouldn't be tuned out because they help control LTFT after the engine warms up. The 02 sensors are relatively cheap and reliable so the way to get through emissions is usually CAT efficiency.
But, it all depends on what you've done to the engine and tune specifics etc....

[brokenwrench]

The ECU can only function in closed-loop mode if at least two of the O2 sensors (1 per bank) are in place. If you're relying on downstream sensors, the ECU has to be able to accommodate for the CAT efficiency, which it probably never intended to do. The downstream sensors on narrow-band ECU's were originally only intended to function basically as cat-efficiency sensors. Personally, I would say use the upstream sensors, but others here may have more applicable experience with this.

[Arsenal2012]

I forgot to mention the car is a C5 A6 Avant 2.8L
The tune was just to get a bit of power out of the already sluggish motor and also eliminate the SAI, Combi and O2s with the wind tunnel effect that always occurs during startup.
So I have not done anything crazy as far as tuning goes rollerton

Would it be safe to assume that if I reinstall the O2s sensors and wires that theoretically will eliminate 4 of the 5 codes?

Then im confused because tank ventilation valve open is probably the sensor wire that went to the tank?
Which just makes me think the Tune was not done right. Am I thinking of it correctly now?

[glennda5id]

Your codes are for the upstream O2 sensors.
It is NOT a common situation to code out the upstream sensors unless it is some sort of car used exclusively for track or racing. Any daily driver car can only benefit from the upstream sensors.
It is common to code out the downstream sensors which are used to determine if the catalytic converters are working properly. The downstream sensors are commonly coded out when the CATS are removed.

Honestly, I would be asking the guy who did the tune exactly what you should and should not be unplugging. We are all just guessing.

[Arsenal2012]

UPDATE TIME

Hopefully I can get some more help

I put the O2 sensors back in and got rid of 3 of 5 codes but I am still getting
P1426 Tank Ventilation Valve Open
P0154 HO2S (Bank 2 Sensor 1) Circuit No Activity

Im guessing the P0154 is from a bad O2 pin and im going to try some contact cleaner on it.






Now I know for the P1426 code rollerton said this stuff is associated with it: "Tank Ventilation is the EVAP system, includes the little N80 valve by the airbox, plastic hoses to the tank, the stupid pump and valve etc..."
I deleted the SAI and also I have a plug that is going to nowhere. From what I can tell the plug to nowhere is supposed to connect to the N80 valve.

Am I wrong to assume that this is the reason that I am getting the P1426 code? I mean shouldn't all of this have been tuned out to not throw codes since it is all connected?
Also do you think if I can find the N80 valve(if I still have it) and just plug it up without it actually going anywhere that the code will go away?

[Arsenal2012]

Thanks for the help Everyone especially you rollerton after plugging in my O2s, reseating bank 2 O2 and ordering an N80 purge valve plugging it up removing my battery and driving for a bit I passed my emissions! :D

As soon as I got home from the emissions site my CEL came on hahahaha

I don't have the Purge valve connected to any hoses though so I'm guessing that is why since the code is reading random misfires which is most likely caused by a faulty hose or no hoses connected in my case.