Help! Power cuts out at 5k rpm (2006 S3 8P)

[Daveyonthemove]

Last weekend my car suffered a power cut out and reduced power whilst gently picking up speed on a dual carriageway. At the time it flagged a fault code, but I didn't think to take a note, I just reset it.
As the clutch was nearing it's end we assumed it was the flywheel having a wobble, so it was pulled apart on the drive and the clutch and flywheel were changed.

As it was on the drive being worked on, the following was done:
New engine oil and filter.
New gearbox oil.
Front and rear diffs fresh oil.
Haldex oil and filter changed.
Brake fluid changed.
Air filter was checked and found to be like new.

On top of the above, since buying it at Easter it has had:
New cambelt and water pump.
New fuel filter.
Carbon engine clean.
New Cam follower.
New Iridium spark plugs.
New coilpacks.
New DV and DV+ (fitted tonight).

As I fitted the DV+ tonight I took it for a drive and it was driving fine until it reached 4.5-5k rpm, and there was a significant drop in power and a jolt. Naturally I let off the throttle at this point and change up a gear.
This has happened in 2nd and 3rd gears so I think it is RPM related.
I have captured a video in 2nd gear to try and demonstrate the problem.




Whilst I do have a Bluefin remap for the car, it is not installed right now as I'm still bedding in the clutch, so the car is in standard form.
I'm baffled as to why it is doing it and would appreciate any advice on what to look at. I have 'Torque' app installed so can do limited logs etc.

 

[NHN]

Have you checked the cam bucket used for the fuel pump, as these can become holed, the fuel pump nillppld deformed & the cam misshaped, you really need to check this tbh as the fuel pressure maybe down on high load.

 

[Daveyonthemove]

Have you checked the cam bucket used for the fuel pump, as these can become holed, the fuel pump nillppld deformed & the cam misshaped, you really need to check this tbh as the fuel pressure maybe down on high load.

Thanks for the suggestion.
I have actually changed this, I just forgot to add it to my list (now edited). As you can see, I have a done a lot and was bound to forget something.

The one I removed was only lightly marked, but I changed it anyway. It's done less than 3k miles on it.

 

[Daveyonthemove]

I have a couple of ideas, but don't know where to start looking.
PCV?
Sensor (which one)?
How do i diagnose them if it's not triggering a fault?

I think it has to be related to the engine's RPM so I don't think it's fuel related, and the air filter is clean so it's not being starved of air.

 

[leshkin]

My recommendation is to go back to the original DV and see if the issue goes away first, just in case the DV+ is faulty or it is highlighting an diagnosed problem elsewhere.

Need to log with VCDS or similar when this occurs t oreally know why it is happening though... This is a nice resource to see what to log and how: http://www.goapr.co.uk/support/datalogging.php

There are five groups of logs that go well together for a particular type of logging. It could be that the fuel return valve is cracking too early and dropping fuel rail pressure, or that the low pressure fuel pump is struggling to deliver, or the DV+ is holding boost better and there is a boost leak elsewhere.

These are just my noddy guesses though.

 

[Daveyonthemove]

Thanks for the reply and pointers.

I probably didn't make it clear in the first post, but this issue was present before this current DV and DV+ was fitted.
My previous DV turned out to be a chinese fake, but in fairness it was on the car for around 6 weeks without any problems.
I'm certain it's not a DV related issue though. Power seemed fine and the boost went as high as 18psi according to Torque, and it barely reached 12psi on a split DV when I got the car.

I have spent a few hours today looking to see if others have had this issue, and small number of people have managed to diagnose either a Crankshaft sensor, or a Camshaft sensor so I have ordered both. No harm in replacing them regardless, and hopefully it will fix the problem. They are cheap enough to try.

Failing that, I have found an ASN member local with VCDS who is willing to check it for me next week, so I have a few days to figure out a plan.

 

[leshkin]

Thanks for the reply and pointers.

I probably didn't make it clear in the first post, but this issue was present before this current DV and DV+ was fitted.
My previous DV turned out to be a chinese fake, but in fairness it was on the car for around 6 weeks without any problems.
I'm certain it's not a DV related issue though. Power seemed fine and the boost went as high as 18psi according to Torque, and it barely reached 12psi on a split DV when I got the car.

I have spent a few hours today looking to see if others have had this issue, and small number of people have managed to diagnose either a Crankshaft sensor, or a Camshaft sensor so I have ordered both. No harm in replacing them regardless, and hopefully it will fix the problem. They are cheap enough to try.

Failing that, I have found an ASN member local with VCDS who is willing to check it for me next week, so I have a few days to figure out a plan.

I was going to say - I just realised that you are not that far from me (I'm in W. London), so I'd be happy to help with VCDS if needed.

 

[Daveyonthemove]

I've been thinking about this all day, and I had a brainwave. As I was unable to detect any fault codes with 'Torque' I remembered recently having an Airbag light that I couldn't detect with it either, even though it was lit up on the dash.
The only way I could clear it myself was to install my Bluefin as it triggers all the warning lights during installation, and then clears them all down as it finalises.
I gave that a try tonight, and as I was waiting I installed the Pro version of Carista on my headunit.
I then went for a drive and was initially able to exceed 5k rpm when building up speed slowly, so I was thinking i'd removed an old fault code that the car was still behaving badly too.
A bit further up the road I pushed it a little bit harder up to 5k rpm and the problem returned, so it's an existing problem and not an old one that needed clearing.

Luckily, this time I was able to scan for it using Carista and I now have an idea what's going on.
P2261: Boost Pressure Control Valve (N249), Mechanical malfunction.

Is this DV related, or something else?

 

[Daveyonthemove]

I've Searched the forum for that code, and it appears that it is a 'soft code' that should make no difference to running of the car, and the fix is to remove the spring behind the piston.

I'm going to revert to the OEM DV I think, but I think the real problem is something else and it's a coincidence that this 'soft' code has flagged up.

 

[Daveyonthemove]

Update:
I have reverted to the Pierburg DV without the DV to rule that out, or pinpoint it as the problem.
The car is still behaving the same, so it's not a DV issue as there was no fault code this time, which confirmed my thoughts in the post above.

So, I'm thinking its a Crankshaft or Camshaft sensor and have ordered both.
If they don't fix the problem, I have two offers of VCDS help which I'm hoping will pinpoint the problem with some live data logging.

If that doesn't pinpoint the problem... God knows. Time to look at a different car maybe?!

 

[leshkin]

Update:
I have reverted to the Pierburg DV without the DV to rule that out, or pinpoint it as the problem.
The car is still behaving the same, so it's not a DV issue as there was no fault code this time, which confirmed my thoughts in the post above.

So, I'm thinking its a Crankshaft or Camshaft sensor and have ordered both.
If they don't fix the problem, I have two offers of VCDS help which I'm hoping will pinpoint the problem with some live data logging.

If that doesn't pinpoint the problem... God knows. Time to look at a different car maybe?!

Sell car? That's quitter talk my man!

Live logging it should help to pinpoint this a bit.

Torque only works with just standard ECU codes and won't support VW Group extensions to the protocol. Carista or OBDEleven are better, with VCDS being one of the best tools for proper logging.

 

[samuelh_888]

Dave get this - it’s money well spent https://m.gendan.co.uk/product_VCV23.html

 

[Daveyonthemove]

Sell car? That's quitter talk my man!

Live logging it should help to pinpoint this a bit.

Torque only works with just standard ECU codes and won't support VW Group extensions to the protocol. Carista or OBDEleven are better, with VCDS being one of the best tools for proper logging.

I'm not wanting to sell it, I actually really like it (up to 4999 rpm) but I've thrown money at this car lately and now it's wanting more. Bit frustrating, but I'll sort it.
Carista does seem very good, I had a play around with the coding last night as well as it finding the codes where Torque couldn't.
Torque does a great job of logging data, so I need both for different reasons.
Maybe I should look at what live data i can capture on Torque?

Dave get this - it’s money well spent https://m.gendan.co.uk/product_VCV23.html

Thanks for the link, I will add it to my list of future purchases, but right now my disposable cash is almost disposed of

 

[Daveyonthemove]

Taken it out for a drive today, same as yesterday but with GF on board to show her.
As before, let the engine get up to temp and gradually pushed RPM's up to 5k in 3rd and it happily passed into 6k with no issue.
Repeated a few times, gradually increasing progressiveness and pushed through to 6.5k with no issue.
2nd gear, exactly the same.

So, it's either fixed itself, or it's waiting for an inconvenient moment to go wrong on me.

Currently have BF installed and OEM DV.

 

[samuelh_888]

Was your GF impressed? She probably thinks you’re making it all up. Mate, my wife wants to burn my car.

 

[Daveyonthemove]

I showed her the video above, and she was with me the first time it happened before the clutch and flywheel change, but it was ****** typical that we had discussed it for 2 hours trying to figure out the problem before I decided to 'show her' and it refused to play up.

Not sure if I'm more glad or annoyed!

 

[leshkin]

Was your GF impressed? She probably thinks you’re making it all up. Mate, my wife wants to burn my car.

Thats because you haven't taken it over 4k rpm mate

 

[samuelh_888]

Hahahah. Thanks.

 

[paddy]

Sams being dragged back to NZ in an attempt to get him away from civilisation and tuning shops .

 

[samuelh_888]

Sams being dragged back to NZ in an attempt to get him away from civilisation and tuning shops .

She thought that would be the only way to separate me from the car. But it’s coming with so her pain will continue!

 

[Daveyonthemove]

Car has played nice all weekend, except for arriving at Ruislip station car park yesterday and finding that reverse had gone on strike.
We managed to resolve that a few hours later when we returned to the car (and a cold engine) and found a bolt had come loose and wedged it's way between the gearbox and the selector.
We must have put it in finger tight when the GB was being refitted as it was used as a guide to get the rest lined up.
Easy resolved, thankfully.
Now hitting 6+K rpm without any problems.