Did you changed your fuel filter ?

 

@ Raf May -

Its the 5th item on his list...

cam follower​

Purge valve​

PCV​

Diverter Valve​

Fuel Filter​

Plugs & coils​

@ Steamy2010 -

My question would be did you look up the fault codes in the Ross Tech Wiki and follow the recommendations? Pay attention to the Special Notes -

• When found in 2008-2013 A3, TT and 2009-2013 A4, A5, Q5 and A6 vehicles with the 2,0l TFSI (EA888) engines it maybe necessary to Reset the Misfire Adaptions.
  • As per TSB [01 13 73] | TPI [2033223] - 01 Engine warning light on after engine replacement EA888 2.0 TFSI
  • To Reset Misfire Adaptions: Clear the 01-Engine fault codes three times in a row in less than 29 seconds "to remove the programed values."
    • https://static.nhtsa.gov/odi/tsbs/2014/MC-10124866-9999.pdf NHTSA

16471/P0087/000135 - Fuel Rail/System Pressure: Too Low
16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected
16685/P0301/000769 - Cylinder 1 Misfire Detected

 

@ Raf May -

Its the 5th item on his list...

cam follower​

Purge valve​

PCV​

Diverter Valve​

Fuel Filter​

Plugs & coils​

@ Steamy2010 -

My question would be did you look up the fault codes in the Ross Tech Wiki and follow the recommendations? Pay attention to the Special Notes -

• When found in 2008-2013 A3, TT and 2009-2013 A4, A5, Q5 and A6 vehicles with the 2,0l TFSI (EA888) engines it maybe necessary to Reset the Misfire Adaptions.
  • As per TSB [01 13 73] | TPI [2033223] - 01 Engine warning light on after engine replacement EA888 2.0 TFSI
  • To Reset Misfire Adaptions: Clear the 01-Engine fault codes three times in a row in less than 29 seconds "to remove the programed values."
    • https://static.nhtsa.gov/odi/tsbs/2014/MC-10124866-9999.pdf NHTSA

16471/P0087/000135 - Fuel Rail/System Pressure: Too Low
16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected
16685/P0301/000769 - Cylinder 1 Misfire Detected

I’ll be honest with you, I’ve not checked anything because I literally know nothing 😂 I’m a complete novice when it comes to this stuff and wouldn’t understand what it was telling me even if I read it. 😩

 

BTW, what are the specifics for your TT...?

• Year: 2008​

• Engine: 1.8 TFSI, 2.0 TFSI, 2.0 TDI, 2.5 TFSI, 3.2 VR6​

• Engine Code*: CDAA, EA888, EA113, CEPA, BUB​

• Gear Box: DSG or Manual​

• Drive Train: FWD or Quattro​

• Model: Coupe​

Has this had any modifications done? (e.g. Stage 1 or Stage 2 remap)

* Your engine code is really important since there are two very different 2.0 TFSI engines available. The code can be found on the VIN tag either in the boot/trunk or inside the front cover of the Owners Manual or Service Booklet. You can also look at the sticker on the left fender near the coolant bottle. Here you can see BUB for the 3.2 VR6.

 

BTW, what are the specifics for your TT...?

• Year: 2008​

• Engine: 1.8 TFSI, 2.0 TFSI, 2.0 TDI, 2.5 TFSI, 3.2 VR6​

• Engine Code*: CDAA, EA888, EA113, CEPA, BUB​

• Gear Box: DSG or Manual​

• Drive Train: FWD or Quattro​

• Model: Coupe​

Has this had any modifications done? (e.g. Stage 1 or Stage 2 remap)

* Your engine code is really important since there are two very different 2.0 TFSI engines available. The code can be found on the VIN tag either in the boot/trunk or inside the front cover of the Owners Manual or Service Booklet. You can also look at the sticker on the left fender near the coolant bottle. Here you can see BUB for the 3.2 VR6.

sorry yes, the details:

2009

BTW, what are the specifics for your TT...?

• Year: 2008​

• Engine: 1.8 TFSI, 2.0 TFSI, 2.0 TDI, 2.5 TFSI, 3.2 VR6​

• Engine Code*: CDAA, EA888, EA113, CEPA, BUB​

• Gear Box: DSG or Manual​

• Drive Train: FWD or Quattro​

• Model: Coupe​

Has this had any modifications done? (e.g. Stage 1 or Stage 2 remap)

* Your engine code is really important since there are two very different 2.0 TFSI engines available. The code can be found on the VIN tag either in the boot/trunk or inside the front cover of the Owners Manual or Service Booklet. You can also look at the sticker on the left fender near the coolant bottle. Here you can see BUB for the 3.2 VR6.

sorry yes, the details:
2009 CDBL I believe
2.0t TFSI 272
Stage 1 ,mapped (by previous owner)
Quattro
Manual

I don’t have the car with me so I can’t check specifically the engine code but I’m pretty sure the above is correct. 😃

 

Tests that I HAVE performed:

compression : 150 in each
Switched plugs and coils around to see if the misfire followed & it didn’t. It stayed in cylinder 1.
smoke test with no obvious signs of leaks.

 

I’ll be honest with you, I’ve not checked anything because I literally know nothing 😂 I’m a complete novice when it comes to this stuff and wouldn’t understand what it was telling me even if I read it. 😩

Honest enough statement. We've all been there. Perhaps you just let the shop get everything done now so you have a good solid baseline. Then you can decide what you want to do and what you're not willing or not able to do. And by that I mean access to tools and a place to work. We have a KB full of information and Workshop Manuals you can download which can get you through pretty much anything you'd want to tackle. But start with the easy DIY things (e.g. air and cabin filter changes, oil change, etc.) and go from there.

 

Sounds like coilpacks, you checked to see all the cables to the plugs are good i.e. no rodents chewed through anything or heat damage.

 

Thanks, I haven’t checked properly now, it’s with the garage now so hopefully that’ll be one of the first things they do. 😬

 

Hang on …. you said:

I began changing bits and pieces such as
cam follower
Purge valve
PCV
Diverter Valve
Fuel Filter
Plugs & coils
it seemed okay for a week or two until yesterday where I took it on the motorway.

so it seems like the plugs and coils are new from ~3 weeks ago?

 

While there is nothing wrong with proactively replacing the parts that you have listed , none of those parts (with the exception of the HPFP tappet) would be directly responsible for causing your low fuel rail pressure issue... and the tappet wouldn't be suspect either unless you found it completely worn through.

You said you've spent months battling this issue but you haven't replaced anything directly replaced to the problem? Rail pressure is created by your high pressure fuel pump (HPFP) and that pressurized fuel is held in your fuel rail waiting for use. The rail is sealed and pressure should remain in the rail unless released. There are only a couple of ways for pressure to escape
1.) Through your injectors
2.) Through your (over) pressure relief valve
3.) Through the Schrader 'release' valve.
4.) Through a leak in the fittings / metal fuel lines.

Leaks big enough to cause noticeable problems should be obvious since you'd likely smell petrol as it sprayed out under great force. I suppose the pressure relief valve could open prematurely but I'd doubt it since there isn't much to fail. That leaves a defective HPFP and / or a leaky injector(s).

Injector issues can be diagnosed by looking at their duty cycle and comparing them with each other. HPFP issues can be troubleshot by comparing demand with actual output.

Some of these tests require specialized tools and may not be jobs for a novice mechanic. There is nothing wrong with seeking professional help once the simple things have been tried. If everything could be fixed with a fuse / filter or system reset there would be no need for trained mechanics.

Hopefully the garage will figure out what is wrong and in won't be too expensive.

 

While there is nothing wrong with proactively replacing the parts that you have listed , none of those parts (with the exception of the HPFP tappet) would be directly responsible for causing your low fuel rail pressure issue... and the tappet wouldn't be suspect either unless you found it completely worn through.

You said you've spent months battling this issue but you haven't replaced anything directly replaced to the problem? Rail pressure is created by your high pressure fuel pump (HPFP) and that pressurized fuel is held in your fuel rail waiting for use. The rail is sealed and pressure should remain in the rail unless released. There are only a couple of ways for pressure to escape
1.) Through your injectors
2.) Through your (over) pressure relief valve
3.) Through the Schrader 'release' valve.
4.) Through a leak in the fittings / metal fuel lines.

Leaks big enough to cause noticeable problems should be obvious since you'd likely smell petrol as it sprayed out under great force. I suppose the pressure relief valve could open prematurely but I'd doubt it since there isn't much to fail. That leaves a defective HPFP and / or a leaky injector(s).

Injector issues can be diagnosed by looking at their duty cycle and comparing them with each other. HPFP issues can be troubleshot by comparing demand with actual output.

Some of these tests require specialized tools and may not be jobs for a novice mechanic. There is nothing wrong with seeking professional help once the simple things have been tried. If everything could be fixed with a fuse / filter or system reset there would be no need for trained mechanics.

Hopefully the garage will figure out what is wrong and in won't be too expensive.

Appreciate they reply, I’ll be honest and say I literally know nothing about engines, I’ve been replacing parts as they’ve come up in different search results as I’ve been trying to figure out the fault. The parts I’ve replaced are all fuel system related. I was just trying to avoid buying the expensive parts such as the HPFP.
there were still other parts on my list such as regulator vales and other sensors but she started driving okay again after the last part was changed. Fingers crossed the shop can find something.

 

Depending of the amount of misfires I guess 💁🏻‍♂️

 

Misfires are constant, it was literally running on 3 cylinders when I had it recovered, sounds like a Subaru 😩

 

So update time:

so far we’ve found out that my coil pack is arcing like mad, we’ve also found that injector 1 is staying open and constantly spraying.

 

There's any number of injector repair/rebuild shops out there which is generally much cheaper than replacing them. Depending on your mileage, it might be time for a new set of coil packs. FYI - don't waste your money on the 'red tops' as they may look nice, but they don't perform any better than the standard black ones.

https://www.ttforum.co.uk/threads/bosch-coil-packs-black-vs-red-suitable-replacement-for-oem-coil-pack.2041210/?post_id=9701525#post-9701525

https://www.ttforum.co.uk/threads/ngk-audi-r8-reinforced-ignition-coils.2024612/?post_id=9550277#post-9550277

 

I’m on 95K miles, I’ll look around for any injector shops. Not even looked at the costs of new ones yet. 😬