Ho guys, I know there are lots of threads but none seem to be covering what I'm experiencing.

 

2011 VRS TSI manual, with ramair intake, custom cat back and now stage 1 remap from Unicorn motor developments in Stockport. So issue is when accelerating on anything other than full throttle, around 2500 - 4000 rpm the car seems to loose power briefly then it comes back. The revs and speed keep increasing but it just seems to stop. As if either fuel, air or turbo has suddenly stopped. Been back to Unicorn, found it running rich so leaned it off and still no change. Ran live logs but couldn't find anything else. Had it checked by my local VAG specialist and Awesomegti and all came back fine. Also no warning lights or fault codes.

 

I've cleaned throttle body, change spark plugs, changed to Audi R8 coils, changed MAP sensor, newest DV and added the GFB DV+ and changed the N75 valve along with the PCV and still no change. 

 

Really at a loss as to what could be causing it or what to check? I've got VCDS so can do logs myself. Fuel pressure and MAF readings all seem to he fine.

The fuelling and turbo boost sound like they are out of sync at intermediate throttle, assuming the map is good, all I can suggest is to check requested and actual boost and physically test turbo actuation either pneumatically, electrically or both to ensure correct operation. 

Requested vs actual boost are ok and awesomegti checked the wastegate actuator and said it was fine. I had a play with it when I fit the DV+ and there was no movement in it. 

So I have this issue from 2500rpm to about 3000rpm. Its like a flat spot. 

My car has K04 Turbo running at 345bhp. It was noticeable when my dv wasn't working so I upgrade to gfb dv+. Still have the issue but not as prominent. 

Ive started using Millers Petrol Max aswell and that's helped a little. 

Random one, but have you done a throttle body alignment in VCDS? I had similar symptoms after a map in a previous VW (TFSI engine though) 

Done it a few times now, and the intake manifold calibration but no change 

What about the Fuel Return Valve? 

I'm going to change this and see if it makes a difference. 

 

https://www.awesomegti.com/search.php?search_query=rs4 fuel return valve&section=content

I've no idea about that. Where is located and how would I check it?

I've seen this sort of scenario a few times on here on the CCZA, and in the cases I've seen reported on here, disappointingly, despite a lot of effort and frustration they have never got to the bottom of it. Whether those few cases I have seen are exactly the same fault or underlying cause as yours is hard to know as they never solved it.

 

Search for @planehazza and read what he tried, but to know avail.

 

It's a bit disappointing when the experts and the remapper say it is all good -  but it is not.  Was the issue evident at all before the remap? Could they put the standard map on and see if the problem is there now?  What has happened in some other cases there has been a little flat spot prior to remap and then after the remap it became more noticeable and severe which is understandable with more fuel / air / boost.

 

@roaddetective is another but I can't remember exactly the issue there.

 

How expert are unicorn, can they properly examine data logs, fuel pressure, etc etc??

 

Sounds like you need to pay for someone who can properly look at the most important parameters that could cause such an issue and that means someone with a lot of experience on this engine. Otherwise you will just start throwing parts at it, fuel pump, fuel injectors, pcv, on top of what you have already replaced.

 

Have you ever cleaned the intake valves? I was astounded at the build up on mine at 69,000.  It caused issues with cold start, light throttle when cold, fuel consumption. It did not resolve planehazza flat spot issues though.

 

17 minutes ago, TheClient said:

I've seen this sort of scenario a few times on here on the CCZA, and in the cases I've seen reported on here, disappointingly, despite a lot of effort and frustration they have never got to the bottom of it. Whether those few cases I have seen are exactly the same fault or underlying cause as yours is hard to know as they never solved it.

 

Search for @planehazza and read what he tried, but to know avail.

 

It's a bit disappointing when the experts and the remapper say it is all good -  but it is not.  Was the issue evident at all before the remap? Could they put the standard map on and see if the problem is there now?  What has happened in some other cases there has been a little flat spot prior to remap and then after the remap it became more noticeable and severe which is understandable with more fuel / air / boost.

 

@roaddetective is another but I can't remember exactly the issue there.

 

How expert are unicorn, can they properly examine data logs, fuel pressure, etc etc??

 

Sounds like you need to pay for someone who can properly look at the most important parameters that could cause such an issue and that means someone with a lot of experience on this engine. Otherwise you will just start throwing parts at it, fuel pump, fuel injectors, pcv, on top of what you have already replaced.

 

Have you ever cleaned the intake valves? I was astounded at the build up on mine at 69,000.  It caused issues with cold start, light throttle when cold, fuel consumption. It did not resolve planehazza flat spot issues though.

 

Hi all. The issue on my previous Octavia VRS TSI was slightly different. Once mapped by Shark, who are now Racingline, the power was great until you hit 6k revs. Then it really held back with a horrible misfire. If you held it at 6k revs, it went into limp mode. Once the engine was turned off and on again, it ran smooth again, but still with the high reving problem. The mapper tried all sorts of things, in fact on one of these trying occasions he had my car for two weeks. Changed plugs, fuel pump at the tank, as well as the one on the engine. Changed coil packs fuel filter, all to no avail. In the end he had to detune the power of the map at the higher revs. That meant it put loads of power down until you got to 6k revs and then it trailed off to hardly any power at all. I got round it by just changing up a gear a bit earlier when giving it some stick. It was still like that when I sold it for the VRS i have now. Have any of you guys with these problems got your car on a rolling road yet with a VW expert looking at the problem? 

It's underneath/behind the fuel rail. 

I'm planning to get a remap and a walnut blast/injector clean done by R-Tech at some point when they can slot me in, maybe Nikki work his magic. 

Maybe it's just a characteristic of the engine. 

The only part which doesn't usually gets changed when tuning stage 2+ are the injectors as uprated ones are very expensive compared to other TSI engines, usually £800 - £1000+. 

 

 

It is very frustrating. I've had a look at the similar threads on here and on the Golf GTI forums and all are pretty much inconclusive. Had the carbon clean done and brand new injectors a couple of weeks before the map so it shouldn't be anything to do with that. 

 

Unicorn seem to be good. Loads of positive reviews and they are supposed to be a VAG tuning specialist. But having said that they didn't really have the car that long so don't know if it's a generic map they developed for 2L TSI and just load that one all the time. I don't want to slag off anyone's work though, but it never happened before the map.  

 

Was debating going to west yorkshire tuning who seem to pride themselves on fixing other maps and they have a lot of experience with VAG, try and get in at Rtech and let them have a look or do what I was going to do in the first place and get APR stage 1. 

 

Did come across a couple of threads on the GTI forum that mentioned the accelerator pedal and with it being drive by wire there's something to do with the signal being sent from the pedal not being right so the ECU doesn't really not what to do as opposed to something happening at that rev range it's more the position of the pedal but I've got no idea.

 

People in the states had similar issues with APR maps and then apparently APR brought out an update and it was fixed. I've got no idea 

9 hours ago, MetalMedic said:

 

Did come across a couple of threads on the GTI forum that mentioned the accelerator pedal and with it being drive by wire there's something to do with the signal being sent from the pedal not being right so the ECU doesn't really not what to do as opposed to something happening at that rev range it's more the position 

 

I assume your VCDS scan hasn't thrown up codes related to throttle input to the ECU? Perhaps the simplest option would be, reset your car to original, to see if it runs as it did prior to the remap and then go to another mapper. 

 

9 hours ago, MetalMedic said:

23 hours ago, Awesam said:

 

Maybe it's just a characteristic of the engine. 

 

 

I am on my fourth 2.0 TFSI / TSI. One of the main attractions for me, is the way that these engines pull smoothly and strongly right up into the redline without hesitation.

9 hours ago, MetalMedic said:

Did come across a couple of threads on the GTI forum that mentioned the accelerator pedal and with it being drive by wire there's something to do with the signal being sent from the pedal not being right so the ECU doesn't really not what to do as opposed to something happening at that rev range it's more the position of the pedal but I've got no idea.

 

Do you ever get a sensation as if the throttle pedal is withholding /fighting back when you are in that rev range? 

 

17 minutes ago, Redboy said:

Im on my fourth 2.0 TFSI / TSI. One of the main attractions for me, is the way that these engines pull smoothly and strongly right up into the redline without hesitation.

I completely agree, it pulls like a train with no real issues. What we have is an issue which affects a small percentage of the CCZ engine. 

 

I'm very tempted to go for a Mk3 because of the GEN3 TSI

 

10 hours ago, MetalMedic said:

People in the states had similar issues with APR maps and then apparently APR brought out an update and it was fixed. I've got no idea 

 

You could persevere and give someone else a go at fixing the issue.   No guarantees though but someone with experience and a good track record maximises your chances.

 

Other option is go back to standard, ask for a refund,  assess  on standard map, then possibly try another map, revo, apr et al.  I'd probably try that.  

No codes at all. Which makes me think the ECU doesn't realise there is a problem.

7 hours ago, Awesam said:

Do you ever get a sensation as if the throttle pedal is withholding /fighting back when you are in that rev range? 

 

I completely agree, it pulls like a train with no real issues. What we have is an issue which affects a small percentage of the CCZ engine. 

 

I'm very tempted to go for a Mk3 because of the GEN3 TSI

 

Pedal feels fine, no resistance. A gen 3 would be ace but was just out of my price range when I got the mk2 :( 

 

 

I am debating going back to stock because it wasn't an issue before the map. Or if it was I couldn't feel it. Think it might be for the best then try somewhere else 

I've been running the like this for over 4 years and its not caused an issue, its just annoying! I notice it more in 4th gear so I stay in 3rd to the redline :)