B7 A4 only boosting to 7psi

[Andrewiffic]

I have a 2008 2.0T A4. Unitronic Stage 1+ chip. 034 Motorsports HFC. I installed the HFC a few weeks ago. It was running great except I noticed a slight loss of power at low rpms when the engine was cold. After it warmed up it was fine and boosted strong. I got a CEL for the secondary cat a couple times, and reset it. I am planning on going in to get it chipped to Stage 2 which will remove the CEL.

Anyway, a week ago I noticed power was way down. I checked the boost with the Torque app (I have a boost gauge on order) and it is now only boosting to 7psi max. After searching on here I read a couple possibilities and tried resetting the ECU by detaching the battery for 1 hour last night, but still no change. Does this sound like a blown Diverter Valve possbily? I have a 2008 so I thought I should have the newest DV that is less prone to failure, but maybe I'm wrong? Any other ideas?

Is this somehow related to the HFC I installed? Because it was running fine and strong before I installed it. And only for a couple weeks after I installed it.

I VAG-Com'd it and there are no codes.

[pezgoon]

I could've sworn no b7 came with the newer style dv and they were all diaphragm but I could be wrong, I'd start there personally if you've never done it

[Andrewiffic]

I could've sworn no b7 came with the newer style dv and they were all diaphragm but I could be wrong, I'd start there personally if you've never done it

Oh good to know. I was trying to find that info and wasn't sure. So the newest revision valve is 06H-145-710-D right? I'll see if I can find out what I have on mine right now.

[axnjaksn]

id get an upgraded dv....gfb or something like that is what a couple of my friends are running...either way that's where id start

[oVeRdOsE]

Oh good to know. I was trying to find that info and wasn't sure. So the newest revision valve is 06H-145-710-D right? I'll see if I can find out what I have on mine right now.

you can take it apart first to inspect. But stage 1+, take no chances, order the revision or the GFB DV+. Take the cheapest. GFB would be a better choice imho.

Worst case, you have a problem with the waste gate, there's a how to how to re-prime it. But the chances are really low that is the problem.
It can be a valve N?? (can't recall) , but again low chances.

Start with the diverter valve. It can only do good on your car.
3 screws, I will take around 1hr to change if you're slow. Do it from under the car.

[Andrewiffic]

Found my problem:


Just ordered a new 710D revision DV. Hopefully will be here soon. Found the best price from GermanParts.ca.

[oVeRdOsE]

Found my problem:


Just ordered a new 710D revision DV. Hopefully will be here soon. Found the best price from GermanParts.ca.

indeed , they got good prices and fast shipping.

[pezgoon]

Yep had a feeling, overdose you were thinking of the N75 valve, which I could've sworn is what the wastegate itself is called? I'm probably wrong though. But apparently right about that DV! Sorry I didn't see your question sooner, glad you pulled it out, your symptoms were yelling either DV or wastegate but I know the DV's are guaranteed to fail with any tune

[kNightsfallen]

I'd be careful... Those turbos don't last much longer than 100k. Not sure what your mileage is... Due to no coolant circulation via after run pump.... Because there is no after run pump. So over boosting them only makes them run hotter and decreases the life expectancy. I just replaced my wife's on her 2008 and she has 115k. And I've replaced more than I can remember for other people.


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[rongeur]

I'd be careful... Those turbos don't last much longer than 100k. Not sure what your mileage is... Due to no coolant circulation via after run pump.... Because there is no after run pump. So over boosting them only makes them run hotter and decreases the life expectancy. I just replaced my wife's on her 2008 and she has 115k. And I've replaced more than I can remember for other people.


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Not going to argue that the K03 hasn't failed, but there are things you can do to help keep the turbo running well for the long run. Number one on the list is to not beaton the car and then just turn it off. You should always give the motor and turbo a proper cool down after beating on it by gentle driving for the final 5-10 minutes before shutting off.

Additionally, if you are tuned,consider shorter OCI (5-7.5k) and be proactive with all recommended maintanence.

My car has been amazingly reliable. Only issue has been a PCV failure after getting tuned.