Too Lean and Too Rich on Both Banks?

[Lamayeee]

Hi all, I’m having an issue where my car will sputter when I start it after I let it sit for an hour or so after driving. It has died on me after starting a couple times as well. For the longest time no codes would come up until very recently and what I got was still confusing. I have taken my car to about 4 shops now all telling me they don’t know what’s going on with the car (of course it won’t do the sputter start when I take it to the shop). I have some friends telling me it’s either the injectors, low pressure fuel pump, or high pressure fuel pump. Here were the codes.

I attached a video of it happening at the bottom.

Your help is greatly appreciated!

P017400 - Fuel Trim, Bank2 System too Lean
Intermittent
Priority - 2
Malfunction frequency counter - 1
Unlearning counter - 255

P017100 - Fuel Trim,Bank1 System too Lean
Intermittent
Priority - 2
Malfunction frequency counter - 1

P017500 - Fuel Trim,Bank2 System too Rich
Static
Priority - 2
Malfunction frequency counter - 1

P017500 - Fuel Trim,Bank2 System too Rich
Intermittent
Priority - 2
Malfunction frequency counter - 2

P017200 - Fuel Trim,Bank1 System too Rich
Static
Priority - 2
Malfunction frequency counter - 1

P017200 - Fuel Trim,Bank1 System too Rich
Intermittent
Priority - 2
Malfunction frequency counter - 2

P125000 - Fuel level too low
Static
Priority - 6
Malfunction frequency counter - 1

P046100 - Fuel Level Sensor "A" Circuit Range/Performance
Intermittent
Priority - 2
Malfunction frequency counter - 1

https://youtube.com/shorts/lEH23qdpGak?feature=share

https://youtube.com/shorts/oPjQYJ295u8?feature=share


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[Mrads]

Fuel pump. My guess would be LPF but it could be HPF. How does the car run when you're driving it?

Likely the injectors are fine because the codes are related to the cylinder banks.

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[Lamayeee]

well when I’m at full load it still seems like it has full power, when I am coasting in 2nd then I can feel it jerking around and the revs will jerk a little too. So with my issues mostly happening at lower rpms I think it could be LPFP?


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[gregg3gs]

Have you figured out the problem? I just picked up a 2014 RS5 and am experiencing similar issues. More specifically P0174, P0171 and today I got the P0087 Fuel Rail/System Pressure.
Car seems to be ok when I drive slow, but from time to time when I take off like a mad man it will cut all power off and stop engine from spinning or sputter.

[BuyTheWarranty]

Have you figured out the problem? I just picked up a 2014 RS5 and am experiencing similar issues. More specifically P0174, P0171 and today I got the P0087 Fuel Rail/System Pressure.
Car seems to be ok when I drive slow, but from time to time when I take off like a mad man it will cut all power off and stop engine from spinning or sputter.

HPFP failing, one or both.

[hahnmgh63]

My first guess would also be the Low pressure fuel pump since you are getting both banks. Each bank has a separate High Pressure fuel pump but only a single LPFP. How many miles on the car? Do you know what diagnostic tests the shop ran? Fuel pressure both low and high would be a must. Most shops don't have the equipement to do the High pressure test but any decent shop should be able to do the low pressure test. Vacuum leaks will cause a lean condition but I'm somewhat puzzled by the Rich conditon faults. Try clearing the faults and immediately do a short drive and rescan and save, then let the car sit overnight and clear the faults and do the same. It would be good to see a Cold start and run scan as well as a warmed up scan.

[A4L]

I just had this exact same issue and it ended up being the low pressure fuel sensor. It was not a cheap fix at $1300 as they have to remove the intake manifold to get to the sensor. I did have them look at the carbon build up while the manifold was off and everything looked good still at 57k miles.

[blueliner]

My car - a 2014 RS5 - is throwing similar codes - but I don't seem to have any impact to performance. My independent shop (which does mostly VAG stuff, the owner has an S6) can't figure it out. I hate going to the dealer but in this instance being on the rarer side of cars it has to go to the experts.

I bought the car about a year ago at 95K and immediately had carbon cleaning done along with new valve cover gaskets.

Now it sits at 99K but has been throwing lean and rich codes. Runs fine though. Will report back in a couple weeks with what the dealer has to say.

[Lamayeee]

Hi everyone, thought i would update. So initially I replaced my LPFP, everything was good until two weeks later when I drove from San Francisco to Oregon, first night I left it for 30 minutes and I had my issue again. So it wasn’t the LPFP for me. Finally got to replace both my HPFPs (even though I got no codes saying it was the HPFPs — I was essentially playing part darts). The tech said when he was replacing one of my pumps, the spring mechanism was broken. So far it’s been three weeks and it’s been fine.


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[hahnmgh63]

Congrats on finally solving this.

[BuyTheWarranty]

Hi everyone, thought i would update. So initially I replaced my LPFP, everything was good until two weeks later when I drove from San Francisco to Oregon, first night I left it for 30 minutes and I had my issue again. So it wasn’t the LPFP for me. Finally got to replace both my HPFPs (even though I got no codes saying it was the HPFPs — I was essentially playing part darts). The tech said when he was replacing one of my pumps, the spring mechanism was broken. So far it’s been three weeks and it’s been fine.


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I had same issue, however mine threw a code for low fuel rail pressure. Drivers side HPFP had collapsed in on itself (spring).

Glad you got it sorted.

[hcubed]

I just had this issue pop up. Scan showed this:

22829 - Fuel Trim; Bank 2
          P0174 00 [096] - System Too Lean
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 92701 km
                    Date: 2022.02.19
                    Time: 15:25:47

                    Engine RPM: 2627.00 /min
                    Normed load value: 27.8 %
                    Vehicle speed: 19 km/h
                    Coolant temperature: 83 °C
                    Intake air temperature: 63 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 13.452 V
                    Unlearning counter according OBD: 39
                    AFS dm: 84.4 kg/h
                    Mean injection time: 1.666 ms
                    Engine operating condition: Part throttle
                    Engine operating condition-Test_Program_Channel 87: 6

22830 - Fuel Trim; Bank 2
          P0175 00 [096] - System Too Rich
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 92740 km
                    Date: 2022.02.20
                    Time: 14:27:15

                    Engine RPM: 705.00 /min
                    Normed load value: 18.0 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 57 °C
                    Intake air temperature: 25 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 14.418 V
                    Unlearning counter according OBD: 39
                    AFS dm: 16.9 kg/h
                    Mean injection time: 1.359 ms
                    Engine operating condition: Idle
                    Engine operating condition-Test_Program_Channel 87: 5
                    Driver-side belt buckle status-Bits 0-7: 137
                    Tumg: 18.8 °C
                    Psr w: 309.69 hPa
                    Engine torque: 65.1 Nm

22655 - Fuel Trim; Bank 1
          P0171 00 [096] - System Too Lean
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 92701 km
                    Date: 2022.02.19
                    Time: 15:25:47

                    Engine RPM: 2426.50 /min
                    Normed load value: 27.1 %
                    Vehicle speed: 18 km/h
                    Coolant temperature: 83 °C
                    Intake air temperature: 63 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 13.499 V
                    Unlearning counter according OBD: 39
                    AFS dm: 76.4 kg/h
                    Mean injection time: 1.723 ms
                    Engine operating condition: Part throttle
                    Engine operating condition-Test_Program_Channel 87: 6

22656 - Fuel Trim; Bank 1
          P0172 00 [096] - System Too Rich
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 92740 km
                    Date: 2022.02.20
                    Time: 14:27:15

                    Engine RPM: 705.00 /min
                    Normed load value: 18.0 %
                    Vehicle speed: 0 km/h
                    Coolant temperature: 57 °C
                    Intake air temperature: 25 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 14.418 V
                    Unlearning counter according OBD: 39
                    AFS dm: 16.9 kg/h
                    Mean injection time: 1.359 ms
                    Engine operating condition: Idle
                    Engine operating condition-Test_Program_Channel 87: 5
                    Driver-side belt buckle status-Bits 0-7: 137
                    Tumg: 18.8 °C
                    Psr w: 309.69 hPa
                    Engine torque: 65.1 Nm

16515 - Fuel Trim; Bank 2
          P0174 00 [237] - System Too Lean
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 92701 km
                    Date: 2022.02.19
                    Time: 15:24:05

                    Engine RPM: 2685.50 /min
                    Normed load value: 33.3 %
                    Vehicle speed: 33 km/h
                    Coolant temperature: 75 °C
                    Intake air temperature: 66 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 14.182 V
                    Unlearning counter according OBD: 40
                    CAN status - engine control module-Bits 0-7: 0
                    CAN status - transmission control module-Bits 0-7: 0
                    CAN status - brake control module 1-Bits 0-7: 0
                    CAN status - brake control module 2-Bits 0-7: 0
                    selected gear-Bits 0-7: 2
                    Cruise control switch actuation-Bits 0-7: 0
                    Cruise control switch actuation-Bits 0-7: 0

16811 - Fuel Trim; Bank 1
          P0171 00 [237] - System Too Lean
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 92701 km
                    Date: 2022.02.19
                    Time: 15:24:05

                    Engine RPM: 2685.50 /min
                    Normed load value: 33.3 %
                    Vehicle speed: 33 km/h
                    Coolant temperature: 75 °C
                    Intake air temperature: 66 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 14.182 V
                    Unlearning counter according OBD: 40
                    CAN status - engine control module-Bits 0-7: 0
                    CAN status - transmission control module-Bits 0-7: 0
                    CAN status - brake control module 1-Bits 0-7: 0
                    CAN status - brake control module 2-Bits 0-7: 0
                    selected gear-Bits 0-7: 2
                    Cruise control switch actuation-Bits 0-7: 0
                    Cruise control switch actuation-Bits 0-7: 0

The first symptoms (2022.02.19) were a jolt at the start of the drive (car had been driven then stopped for 2 hours) followed by two stalls of the engine while stopped. I drove the following day (2022.02.20) and just noticed the new codes for system too rich on both banks. When I drove the car to get it smogged (here in CA) on 2022.02.23 the CEL illuminated. I just replaced both HPFP and cam followers. The cam followers looked good with no visible damage or wear. The HPFP looked good and the springs seemed alright.

I cleared the codes and hopefully we have the issue sorted.

[wakesurfin]

I had same issue, however mine threw a code for low fuel rail pressure. Drivers side HPFP had collapsed in on itself (spring).

Glad you got it sorted.

Does anyone have any new experience with this? I'm having the same issue for the last two years or so. Dealer replaced my HPFPs about 3 years ago at +/- 40k miles (+/-63k now) but I'm getting same codes as mentioned above. Its run fine for the last year / 5k but last week started idling roughly, shutting off, and it smells like the cats are unhappy for some reason....lotsa sulfur smell in the garage.

I've had it to the dealer and two indies and neither can figure it out - really don't want to start throwing $2k in dealer parts and labor in hopes of figuring it out.... I've replaced a couple of sensors but they're all stumped. I bought Vagcom but haven't tried posting to their support yet.

[TontoLoidRS5]

Could it not be the LPFP? The posted error codes aren't at extreme loads.

Does anyone have any new experience with this? I'm having the same issue for the last two years or so. Dealer replaced my HPFPs about 3 years ago at +/- 40k miles (+/-63k now) but I'm getting same codes as mentioned above. Its run fine for the last year / 5k but last week started idling roughly, shutting off, and it smells like the cats are unhappy for some reason....lotsa sulfur smell in the garage.

I've had it to the dealer and two indies and neither can figure it out - really don't want to start throwing $2k in dealer parts and labor in hopes of figuring it out.... I've replaced a couple of sensors but they're all stumped. I bought Vagcom but haven't tried posting to their support yet.

[Belialith]

I have had this fault intermittently for going on 2yrs now and 30k+ miles with no resolution in sight. HPFP, LPFP, Carbon Clean all have been done/replaced. It seems more prevalent with warmer temps and I get it more consistently when getting close to due for an oil change. I just did my oil today and the drive over to my shop it was bogging down when coming to a stop but changed the oil and it has no issues now.

The only thing left I can really think is maybe a leaking injector or maybe a failed o-ring on one of the injectors that for some reason hasn't degraded further. But this isn't really supported by my fuel trims and other logs I have done to try and find the issues before throwing more parts and money at it.

I had initially thought my issues was resolved as I had found a chunk of my HPFP spring in the cam follower channel but that didn't change anything.

I have a similar situation to wakesurfin above where it seems like the cats are going out which is a known issue on these cars but haven't looked into it further.

I also get a very small evap leak code with my other faults. There is a Technical Service Bulletin regarding that fault but that didn't fix the code so I imagine it is something else entirely.

[hahnmgh63]

If it was an injector I think it would show up as a misfire, have you checked your misfire log? The misfire log will log misfires long before they become soft or hard codes. As for the Cats, your cats are going out for sure, it just depends on how bad. I've video inspected the cats on a 26.5k car and a 31k miles car and on both you could already see the Cats degrading. They all start with pock marking on the inlet side and slowly (relatively) degrade into deeper crevices and cracks. They all come apart slightly differently too, some make break off in small chunks and flow mostly if not all the way through the exhaust over time or stick in the corners of the Resonators or Mufflers until they break down further. Some may break into large chunks that can obstruct your exhaust and cause all kinds of issues and eventually engine damage. With a Video inspection camera it is an easy inspection to do, anyone with over 40~50k miles should do it and then monitor if every 10k. All you have to do is pull the front O2 sensor out.

[TontoLoidRS5]

Also check for other signs like rough idle at start up, listen for vacuum leaks, consider carbon clean. Can be small leaks of fuel, smell in the oil cap for fuel, take an oil sample, check air filters...oil level, VVT actuators oil pressure controlled.

[Belialith]

I get a rough idle once every 100 starts probably. Never found a vacuum leak. Carbon clean done within the last 10k. Air filters and oil change done within the last 500mi. Fuel smell never really noticed in the oil so not too sure there.

Catalytic converter going out sounds like my issue more than likely but the prospects of dealing with it doesn't sound cheap or fun. Replacement is engine out as far as I know.

[hahnmgh63]

Yep, no other way than engine out. It's that way on a lot of the newer cars though, especially when they stuff a bigger engine in there than what it was really meant to hold (4cyl 2.0t, V6 3.0t).

[TontoLoidRS5]

Yep, no other way than engine out. It's that way on a lot of the newer cars though, especially when they stuff a bigger engine in there than what it was really meant to hold (4cyl 2.0t, V6 3.0t).

I think the audi/VAG V6s are engine out also for the timing chain. Better do them together on the V8s.

[TontoLoidRS5]

I get a rough idle once every 100 starts probably. Never found a vacuum leak. Carbon clean done within the last 10k. Air filters and oil change done within the last 500mi. Fuel smell never really noticed in the oil so not too sure there.

Catalytic converter going out sounds like my issue more than likely but the prospects of dealing with it doesn't sound cheap or fun. Replacement is engine out as far as I know.

Maybe coolant temperature in thre log is an indication then of how far on the way each of them is.

With highet ethanol content gas it should idle less roughly (when warm) but will read more lean under load.

Rich reading at warm idle is the inspection scenario meaning it will cut fuel a bit too much but as long as it doesn't stall then maybe will pass even with just standard gas. If it is reading too rich you need as much oxygen in as possible via fuel and/or having done carbon clean, filters etc. More oxygen at working temp of catalytic converters meaning more reaction until they are completely out.

[Belialith]

It only ever stalls when coasting to a stop. Sometimes if left idling for a long time it will do so as well. So that seems in line with what you are saying. I only ever put 91 without ethanol in it as that is all I can get around me.

[TontoLoidRS5]

get o2 sensors with a small catalytic converter on it for the down flow side. maybe it is sufficient to make sure you have enough oil for the VVT actuators.

[hahnmgh63]

You can check the Cats easy, just buy a cheap Amazon Iphone/Android Video inpection camera. The O2 sensor is a 22mm/7/8" wrench needed, shouldn't have to be the special O2 sensor socket. Only need to inspect the front side of the Cat, not the rear one. Yes, all Audi V8/V6 motors since the mid 2000's require engine out to get to the Timing chain/guides. A lot of great videos on this on Youtube, I think the best is from a UK company called Vagtechnic.
The guides are much improved over the earlier (2005~2012) 4.2's but there are always the possibility's of a piece of the Phenolic plastic breaking off which can cause a big change in one of the banks timing. Dirty oil causes a lot more wear on the guides so use top quality oil and change frequently. Not much you can do about age and heat though, it will eventually catch up to us all.

[TontoLoidRS5]

Personally, I will let the chain come off when it happens unless I get a really bad reading, as Vagtechnic had a 2010/2011 that had spun something like 90 degrees without needing an engine rebuild just do the timing parts; gut the cats if needed and put spacers on the O2 sensors.

We have emissions tests here and I have seen clear case of bad cats on an 2010/2011 based on the report. If I need working cats they will go downstream with ECS extension cable for the O2 sensors.