b7 rs4 bank 2 running rich and lean with codes on the same bank?

B6/7 S4/RS4
#1

after some hard driving i’ll receive a CEL for bank 2 sensor 1 stuck on rich… also will receive a bank 2 code for lambda lean. (weird how can one bank be rich and lean at the same time?)
every now and then i get codes for bank 2 sensor 2 (heater circuit) and bank 1 sensor 2 (heater circuit) i think thats because i gutted my down pipe pre cats and run spacers on the rear o2 sensors?

i did the cleaning to maybe see if it fixes the problem, no… i misfire at idle very little. with a misfire counter ill get misfires on cylinder 1,3,5,6,7 only at idle or under 2600 rpm. i did swap injectors bank 2 with bank 1 to see if the rich/lean codes travel but didn’t swap #5 and #3 as i couldn’t get them out without breaking the plastic tabs on them with the audi jerk off tool.

128k on the motor
fresh carbon clean 7 days ago.
plugs are new, coils are a year old.
always run shell 93 v power

ecu 2 codes:
4 Faults Found:

004416 - Oxygen (Lambda) Sensor; B2 S2
P1140 - 008 - Internal Resistance too High - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 0
Fault Frequency: 2
Reset counter: 255
Mileage: 205590 km
Time Indication: 0

         Freeze Frame:
                RPM: 4345 /min
                Load: 35.3 %
                Speed: 114.0 km/h
                Temperature: 92.0∞C
                Temperature: 17.0∞C
                Absolute Pres.: 1010.0 mbar
                Voltage: 12.954 V

008344 - Post-Catalyst Oxygen (Lambda) Sensor Correction; Bank 2
P2098 - 002 - Too Lean
Freeze Frame:
Fault Status: 01100010
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 205780 km
Time Indication: 0

         Freeze Frame:
                RPM: 2020 /min
                Load: 26.3 %
                Speed: 77.0 km/h
                Temperature: 92.0∞C
                Temperature: 15.0∞C
                Absolute Pres.: 1010.0 mbar
                Voltage: 13.462 V

008600 - Oxygen (Lambda) Sensor B2 S1
P2198 - 002 - Signal too High (Rich)
Freeze Frame:
Fault Status: 01100010
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 205780 km
Time Indication: 0

         Freeze Frame:
                RPM: 2009 /min
                Load: 33.7 %
                Speed: 77.0 km/h
                Temperature: 92.0∞C
                Temperature: 15.0∞C
                Absolute Pres.: 1010.0 mbar
                Voltage: 13.462 V

000345 - Oxygen (Lambda) Sensor B2 S2
P0159 - 001 - Response too Slow
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 205804 km
Time Indication: 0

         Freeze Frame:
                RPM: 2193 /min
                Load: 28.6 %
                Speed: 84.0 km/h
                Temperature: 88.0∞C
                Temperature: 10.0∞C
                Absolute Pres.: 1010.0 mbar
                Voltage: 13.335 V
#2

bank 2 timing retard logs, MAF, AF ratio, forgot tq but not a problem.

https://drive.google.com/file/d/0B27qXp5nBUKtVFA0ME1DenZ0OEU/edit?usp=sharing

#3

must be the JHM tune if flyingtomatoes and badblueRS4 were to be believed since the last time someone had similar codes, they blamed JHM.

OH WAIT…Tony is on stock tune. Hmm…could it just be that RS4s have problems when they’re 8 years old?

Log looks good. Car looks very quick. Power is about right for piggies and catback but no tune to take advantage of it. Stock tune is holding you back quite a bit. But your lightweight rotating parts and strong density altitude mean the car is accelerating VERY well. Up around 620 RPM/second. Very solid for stock tune.

MAF is hitting mid-high 150s which as I said makes sense considering the stock tune.

Still pulling a bunch of timing despite the cold weather and recent maintenance. Was this pre or post carbon clean?

#4

before the cleaning, the logs were:
https://docs.google.com/file/d/0B27qXp5nBUKtWFFNLVMtaF81aGc/edit

#5

interesting. Very similar. How bad was the carbon?

#6

I’d bet you need some new O2 sensors.

#7

pretty bad, and wet saki…
the rear 02 sensors don’t monitor fuel trims or anything like that. do i highly doubt they would cause a misfire at idle or rich/lean codes

#8

The rears should monitor long term fuel trims.

I’d make sure you don’t have any false air making it into the manifold by a bad gasket seal. I would personally just replace the sensors because it wouldn’t be the first failures we’ve seen.

or it’s your JHM tune

#9

I’m on stock tune… i had the same rich/lean codes before the carbon clean as well… do you guys think it can be an exhaust leak from the down pipe? i had to use nuts and bolts for the driver side which is bank 2, where my codes are… and the shop that gutted them out used cut the pre cats out and welded them back up together. possible air leak here?

#10

yes we know, we’re joking.

I would try to contact JHM directly. You hvae about $5,000 in JHM parts on your car, and that should buy you a little tech support.

I have PM’d a couple of their employees to read this thread (that’s why I asked you to start it) to see if they have any thoughts for you.

#11

cool, thanks saki

#12

I had an O2 sensor code on my S4 because of an improperly sealed DP flange. The O2 was seeing false air from that. So your concerns at definitely valid.

#13

do you recall exactly what that code read?

#14

Tony, you came to the right place.

All your codes came at part throttle cruising along. The missfires account for the mix in the AFR. If you don’t get a complete burn and you’re getting missfires, the oxygen content will be off target.

Start with this.

Fuel filter replacement? When was the fuel filter replaced?
Spark plugs? when were they replaced?
Also how about a vac leak after the carbon clean?
Were there any codes from the other ECU?

Let’s start with that and go from there.

#15

good point…all were at 20-30% throttle

#16

yes all with part throttle… codes were the same before and after the carbon cleaning… plugs are now new(after the cleaning) fuel filter is 1 year old exactly. codes on the other edu was only bank 1 sensor 2 heater circuit.my breather house was found to be broken and i temporarily fixed it for the time being with rubber tube over the broken area and clamps on the out side. tested it, and its air tight good for the time being.


http://i1025.photobucket.com/albums/y318/rs4tony/image-1.jpeg

#17

Tony,

I am sorry to hear you are still having this issue!

An exhaust leak before the sensors will definitely cause them to do some wacky things. I would look into that right away. I know your exhaust is fairly loud, so it could be masking the sound of an exhaust leak. If you don’t have the time to check if the DP is tight against the header, try and look up in there with a flashlight to see if you can see any black carbon around the exhaust (flange and where that shop welded) indicating a leak. (Note: even if you do not see any carbon, it does not mean its not leaking so it is best to check and see if everything is tightened properly.)

#18

Does this sound like an injector problem?

A leak sounds more believable because if I’m at idle and rev to 1,600 rpm I smell exhaust in the cabin with the windows up and air conditioner/heat on

#19

I think you have two separate issues. The o2 codes could be exhaust leak and the misfires are something else.

#20

I’ll look over the downpipes now and check coil pack connections as well