Choke above 4200rpm with no CEL (tsi)

[max14632]

Hi everyone. I just bought a 2010 2.0t quattro a3. The issue is if i floor it at about 4200rpm the car chokes, feels almost as if i tapped the brakes really fast. If i do about 50% throttle it happens at around 4500rpm, not as violent but still the same choke. Before 4k rpm car drives perfectly fine, consistent, no issues at all. Problem is i dont get a check engine light, even if i do few WOT pulls in a row every time hitting choke point. After the “choke point” if i let go of the gas pedal and let the rpms fall, the car drives fine again like nothing happened. If i keep the gas pedal while its choking it starts to shake violently and rpms bounce at around 4k.

So far i replaced a diverter valve with an upgraded 1, and also replaced a n75 valve. That made no difference. HPFP is putting out 2200 psi and holding all the way to the choke point(4200rpm), turbo seems to be working too, ive seen 10psi peak and then it falls off to about 6-5psi shortly after(im not sure if thats normal numbers). I have logs but the app wont let me post if i attach them. Let me know if you guys have any ideas or if any of the numbers seem off. Thanks


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[max14632]

I should mention that i suspect someone was changing the head on this engine before. Im not sure if they could have messed something up with timing but i figured it would show on how the car performs overall or starts which i dont see. Car starts right away with no weird sounds and pulls without any hiccups


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[NHN]

Check the plugs & coils, also check the cam follower, make sure it's not holed as this rounds of the cam & creates issues of similarity.

 

[max14632]

I swapped the coils from my a4 into it along with the new spark plugs yesterday, made no difference. Since my a3 has a tsi engine it didnt have the cam follower issue older a3s had. I checked it out when i removed the hpfp, its the roller type and it seemed to be fine.


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[NHN]

What about the coils?

 

[max14632]

What about the coils?

Coils i swapped from my 2007 a4, i know they are in working condition so i swapped them in and nothing changed. Im really blanking out with this issue and dont really know where else to look


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[SootySport]

You have the same model as me. Mine did this after a stage one remap when I go full throttle and it was the dsg box hesitating as it dropped a gear on kick down, only does it occasionally though. If it were coil packs or spark plugs faulty, the engine light would come on and a fault code recorded. If the gearbox oil has not been changed for 30k miles, do this first.

 

[max14632]

You have the same model as me. Mine did this after a stage one remap when I go full throttle and it was the dsg box hesitating as it dropped a gear on kick down, only does it occasionally though. If it were coil packs or spark plugs faulty, the engine light would come on and a fault code recorded. If the gearbox oil has not been changed for 30k miles, do this first.

Can you tell me more about it? Dsg was my first thought but i ruled it out after selecting “manual” mode and flooring it. Seeing as it stayed in the same gear but still choked at 4300rpm i figured since there wasnt a gear shift its probably not the gearbox. That was just my train of thought, im not really familiar with how dsg work. The car got 100k miles(180?k Km) and it might have never had a dsg oil service


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[SootySport]

As you had it manual mode you maybe right, I’ve never tried manual mode to see if it makes difference, I will try it though. If you have no record of dsg oil service, you definitely need to have that done even if it’s nothing to do with your problem.

 

[max14632]

As you had it manual mode you maybe right, I’ve never tried manual mode to see if it makes difference, I will try it though. If you have no record of dsg oil service, you definitely need to have that done even if it’s nothing to do with your problem.

Yeah it was definitely in the plan right after regular oil change. Quick question, when you driving normally in the “D” gear and then start slowing down off of freeway for example do you feel the downshifts or is that something im not suppose to feel?


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[SootySport]

It should be almost imperceptible when changing cogs if driving normally, if you are caning it all the time then it will be a bit more noticible. I don't ever know what gear I'm in auto mode, I rarely feel itchange gear.
When you changed the DV was it an all plastic affair or metal?

 

[max14632]

It should be almost imperceptible when changing cogs if driving normally, if you are caning it all the time then it will be a bit more noticible. I don't ever know what gear I'm in auto mode, I rarely feel itchange gear.
When you changed the DV was it an all plastic affair or metal?

Yeah my gear changes are more noticeable than yours it seems. DV i changed is from go fast bits and it was all metal. It didn’t really make a difference from the stock one.


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[max14632]

Ended up finding the problem and fixing it. For anyone who has the same symptoms as me and wants to know the solution: replace your rpm sensor (g28). Mine was in a terrible condition but showed no signs of it until i took it out. One way i was able to pin point the problem was drive on the highway in manual mode at about 3800 rpm and then dropping the gear. That will cause your rpm to fly up to around 5k which is above the point of choke. It then threw a check engine and code p0321 which is crankshaft position sensor. From there it was the matter of googling and ordering a genuine audi sensor from ecstuning. Good luck


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