RPM limit issue after maintenance work.l

[Denio24]

So i just completed some service on my a4, oil cooler and oil filter bracket gasket. Everything runs great now no leaks. Boost holds fine as well. However when passing 3500 rpm sounds like the engine cuts spark and makes popping noises in my exhaust most likely due to rich condition. Did I forget some sensor? This also happens if i rev the engine in neutral.

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[Denio24]

Forgot to mention, but I also replaced my PCV with the oem updated revision one. Is it possible that a boost leak from there could cause my issues? I did some logs w/ VCDS and it says it's boosting normally but my boost gauge is a whole different story. The max I saw was 7 psi. Any idea how to properly boost leak test the 2.0t? I have read that you have to remove the rear pcv vent to the turbo from the valvecover and plug it. No idea how it's done.

[Audiian24]

I think you're in limp mode


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[Denio24]

I think you're in limp mode


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Negative, just took the car for a test drive and instead of going WOT right away I gradually stepped on the accelerator until i bottomed it out. So I don't think this is rpm specific. My boost gauge is showing .5 bar (7 psi) max.

[Okedokey]

Any codes

[Denio24]

Yes, 2 codes came up that I never had before. Wiring has been checked.

2 Faults Found:
004372 - Oxygen (Lambda) Sensor; B1 S2 
               P1114 - 008 - Internal Resistance too High - MIL ON
             Freeze Frame:
                    Fault Status: 11101000
                    Fault Priority: 2
                    Fault Frequency: 2
                    Reset counter: 255
                    Mileage: 197922 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 2387 /min
                    Load: 7.1 %
                    Speed: 52.0 km/h
                    Temperature: 90.0°C
                    Temperature: 9.0°C
                    Absolute Pres.: 990.0 mbar
                    Voltage: 14.097 V

000320 - Oxygen (Lambda) Sensor B1 S2 
               P0140 - 004 - No Activity - MIL ON
             Freeze Frame:
                    Fault Status: 11100100
                    Fault Priority: 2
                    Fault Frequency: 2
                    Reset counter: 255
                    Mileage: 197922 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 2387 /min
                    Load: 7.1 %
                    Speed: 52.0 km/h
                    Temperature: 90.0°C
                    Temperature: 9.0°C
                    Absolute Pres.: 990.0 mbar
                    Voltage: 14.224 V

Readiness: 0000 0100

[allstock]

Why don't you go ahead and check the aging of the two sensors with your vcds

[Denio24]

Test completed. Aging of both sensors pre-cat and post cat says B1-S1 OK & B1-S2 OK.

How could a bad o2 sensor cause jerking at higher rpm? I start building boost to a good point then around 4k rpm it just jerks and the tachometer just goes back and forth. It just seems that if I try to get some performance out of this car it always breaks down. Just wondering why this has all happened as the car was running just fine before. Gets on my nerves

[allstock]

O2 sensors have a direct correlation to air and fuel control by the ecm. I'd do some serious data logging of as many relative measuring blocks as possible in "measuring blocks and adv measuring values". You have to the tool to help you.

[Denio24]

Any tips on where i should start and what to look at?

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[allstock]

Air

Fuel

Spark

and take into account whatever tune you have.

Sorry I couldn't be more of help, perhaps others'll chime in.

[Denio24]

Just noticed that my lpfp duty % is 57 at idle. Could this be an indicator that I could be experiencing a fuel cut? Just to describe the issue one more time, when either revving the engine or WOT, usually higher up in the RPM range say 4k RPM, could be less, could be more, the engine wont increase revolutions and I hear a pop pop pop in the exhaust with the tachometer needle jumping back and forth. This feeling is similar to what you would feel with bad spark plugs, like a jumping and jerking when you add some gas, though it only happens higher up in the rpm range when more fuel is required due to forced induction. Hopefully an audi expert can chime in here.

[johnruan]

Did this happens after you change out your pcv? Maybe switch back the old one and see if it's still same issue.

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[JDillon15]

Forgot to mention, but I also replaced my PCV with the oem updated revision one. Is it possible that a boost leak from there could cause my issues? I did some logs w/ VCDS and it says it's boosting normally but my boost gauge is a whole different story. The max I saw was 7 psi. Any idea how to properly boost leak test the 2.0t? I have read that you have to remove the rear pcv vent to the turbo from the valvecover and plug it. No idea how it's done.

I know there are two different PCVs, split by manufactured year. If you still have the old PCV, maybe swap that in and see if that's the issue.

Or check here and make sure you got the right one.

[Denio24]

Just changed between the P revision as I have an '08 and my catch can setup and made sure both were securely attached to the valve cover and no difference with either one. Car still jerks when i push it after 3-4k RPM. I will post lpfp & hpfp fuel pump data shortly combined with MAF logs. There really arent any boost leaks right now just my boost gauge is messed up - will have to contact [email protected]. Checked boost via vcds and all is fine.

Those previous p1114 codes I believe could also be bogus as I'm running a test pipe.

[Audiian24]

Is this "jerk" your describing a misfire? Have you changed your spark plugs and coil packs? Does your check engine light flash when this happens?


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[Denio24]

CEL does not flash when this happens, at least not multiple times. Only comes on once and stays lit - and that only happens sometimes. Plugs and coils have been changed with all OEM components. I've had misfire issues in the past not only with the b7 but a b6. I know what you are talking about you feel tons of jerking and the CEL will flash multiple times.

Got a video of it this time at idle.



.....anddd more codes

4 Faults Found:
000313 - Oxygen (Lambda) Sensor B1 S2 
               P0139 - 004 - Response too Slow - Intermittent
             Freeze Frame:
                    Fault Status: 00100100
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 197948 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 2516 /min
                    Load: 7.1 %
                    Speed: 54.0 km/h
                    Temperature: 90.0°C
                    Temperature: 8.0°C
                    Absolute Pres.: 990.0 mbar
                    Voltage: 13.970 V

004372 - Oxygen (Lambda) Sensor; B1 S2 
               P1114 - 008 - Internal Resistance too High
             Freeze Frame:
                    Fault Status: 01101000
                    Fault Priority: 2
                    Fault Frequency: 3
                    Reset counter: 255
                    Mileage: 197948 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 3319 /min
                    Load: 7.1 %
                    Speed: 96.0 km/h
                    Temperature: 89.0°C
                    Temperature: 6.0°C
                    Absolute Pres.: 990.0 mbar
                    Voltage: 14.224 V

000320 - Oxygen (Lambda) Sensor B1 S2 
               P0140 - 004 - No Activity - Intermittent
             Freeze Frame:
                    Fault Status: 00100100
                    Fault Priority: 2
                    Fault Frequency: 2
                    Reset counter: 255
                    Mileage: 197958 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 3319 /min
                    Load: 7.1 %
                    Speed: 96.0 km/h
                    Temperature: 89.0°C
                    Temperature: 6.0°C
                    Absolute Pres.: 990.0 mbar
                    Voltage: 14.224 V

000801 - Engine Speed Sensor (G28) 
               P0321 - 008 - Implausible Signal - Intermittent
             Freeze Frame:
                    Fault Status: 00101000
                    Fault Priority: 2
                    Fault Frequency: 1
                    Reset counter: 255
                    Mileage: 197961 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 0 /min
                    Load: 0.0 %
                    Speed: 0.0 km/h
                    Temperature: 89.0°C
                    Temperature: 12.0°C
                    Absolute Pres.: 990.0 mbar
                    Voltage: 13.970 V

Readiness: 0010 0000

maybe it's the engine speed sensor?

[allstock]

Speed sensor could be one thing to check. Look at the freeze frame; it reads as if it was triggered with no rpm, no load, and no speed. Could be the reason for an implausible signal in that regards.

That 57% reading is the lpfp is how much work load it's outputting and that is in spec.

[Sanjman]

Sounds like the g28... Replaced mine and all was good! Look for my DIY

[Denio24]

Sounds like the g28... Replaced mine and all was good! Look for my DIY

Wouldnt a g28 trigger a no start condition not this rpm issue im having?

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[Sanjman]

Wouldnt a g28 trigger a no start condition not this rpm issue im having?

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It might after some driving but for me it didn't for a few drives, I replaced it and then had the difficulty starting. But I cleared codes verified connections and car started fine after.

Without a vag com I would have instantaneously guessed that it was a failing camshaft so I was pretty happy that I had an easy and cheap fix.

[Denio24]

Looks like this guy had the same symptoms.



Going to replace it soon. Any idea on what sensor I should purchase? I also have some sensors from a b6 though I think the only difference is a longer wire. Will post to update if the issue has been solved.

[Sanjman]

Looks like this guy had the same symptoms.



Going to replace it soon. Any idea on what sensor I should purchase? I also have some sensors from a b6 though I think the only difference is a longer wire. Will post to update if the issue has been solved.

You're going to learn the hard way when people get on you for not searching but here you go
http://www.audizine.com/forum/showthread.php?t=679172

[Denio24]

At idle the LTFT is now 8.0. Isn't that a little high as the values should be as close to 0 as possible? Could there be a possible restriction or faulty fuel system component?..... because the LTFT is telling me that that the ECU is adding fuel.

I don't even know where to start - perhaps Old Guy can chime in. The LPFP pressure looks fine it is between 5 & 7 bar for the most part, but with occasional dips to around 3 bar when there is greater pressure in the fuel rail . Let me explain. The question is, should the LPFP pressure be above or as close as possible to 5 bar at all times, or is it normal for the pressure to dip down to 3 when there is increased pressure in the fuel rail when at WOT? This is what I see in my logs: for example, when going WOT, fuel rail pressure will be 117, and the LPFP pressure will dip as low as 3.0 Bar.

[Denio24]

I never found the issue but I forgot to post what the cam follower looked like. I think the cam lobe was also a little scored but nothing too bad. I will most likely replace it eventually. I purchased this car used so I have no idea about the history behind it. I am led to believe that this was a fueling issue because as soon as I changed out the cam follower the issue stopped. Car is 100% solid now to redline. For those who really push their cars, I recommend replacing your follower every 5-10k miles, whatever your OCI (oil change interval) is. Here is an image of the follower. I believe the way these followers fail is they first start developing stress cracks and eventually they break through the center. It's not really taking off metal, unless your camshaft is scored, but more like high impacts that eventually brake it in to pieces.

[JDillon15]

I never found the issue but I forgot to post what the cam follower looked like. I think the cam lobe was also a little scored but nothing too bad. I will most likely replace it eventually. I purchased this car used so I have no idea about the history behind it. I am led to believe that this was a fueling issue because as soon as I changed out the cam follower the issue stopped. Car is 100% solid now to redline. For those who really push their cars, I recommend replacing your follower every 5-10k miles, whatever your OCI (oil change interval) is. Here is an image of the follower.

That does look a little abnormal to me. Usually, they're pretty darn smooth and perfect circles in the middle. You're has some obvious indentations.

[Denio24]

If I run the tip of my nail across the top of it I definitely slightly feel the abnormalities.

In the next 4k miles I will service my follower again and possibly convert to the stud kit. It will be time for me to really inspect the cam lobe. After googling cam follower failure and looking at images, it is common for the follower to break at the four oil holes. There is a high performance follower at HPFPupgrade.com for those who are interested. LINK