Audi 2.0 TFSI no boost , major headache

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ya5

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Hi .. new to here, been lurking for some time now..
Could do with some help ..
Have brought a 2005 A4 2.0 TSFI which has had a light bump to front.
All repaired now and itching to drive it, but cant :frown:

Car doesn't rev over 4k and turbo doesn't 'kick'
Ive had every possible reader scanner plugged in ( snap on , vcds , etc ) nothing shows up as a fault.
So far, ive fitted brand new genuine N75 valve , diverter valve , PVC. All of which have made no difference whatso ever.

Car starts, idles, drives fine. Just as soon as it hits 4k rpm its like its hit a brick wall !

Any pointers , advise , tips , help what to check or problem could be ??
Ready to put petrol and match to it :rage:
Thanks
 
I would first check if you dont have any boost leaks. Get a smoke test done. If it had a bump, there is a chance the intercooler cracked on a mount and leaks air.
 
Thanks for the quick replies guys.
I should have mentioned, ive had a new intercooler fitted as old one got busted.
Had a smoke test done, which prompted to replace PVC as that's where leak was detected.

Just at point where don't know what to try or anything now :blink:
 
You need to plug vcds in and go for a drive , do some logging see what is happening with boost and boost control.
 
Are you sure the pcv, n75 and all the vacuum pipes are connected the right way?
 
PCV and n75 are all plumbed in correctly, have checked against another car.
I will have get it hooked up to vcds and go for a drive.
Will report back with the findings.
 
Well still no go :chargrined: ...
Cars been dropped off to a reputable garage.
They have checked everything over and all is ok. Computer says everything is fine. All is fine :help:
Car just hits this damn brick wall at 3k rpm.
Only thing they can think of is, the cars been previously remapped and to put it back to factory map.
So they have sent off for the factory map.

Is it petrol an match time ? :rage:
 
sO if the turbo doesn't kick in surely its got to be something to do with that? although no log faults etc for turbo unit has it been checked out ?
 
I would think a good place to start would be to do some live driving/logging of MAF, Boost, High Rail Fuel pressure and low rail fuel pressure, misfires, timing retardation etc. See what looks odd there.

Is your turbo kicking in at all, or does it only work until 3k/4krpm?

Mine did that once - but it also gave off a fuelling code. Changed the cam follower and all was fine - so it could be something in the low pressure/high pressure fueling etc?
 
Also, as an aside - when I got my car the PCV was bust - which meant boost had been being directed into lots of places it shouldn't have. This meant I had a couple of oil leaks (from the rear main oil seal and the sump) - you might want to watch out for them.
 
Its like there is no turbo at all, and just when turbo should "kick" it just hits this brick wall.
Intercooler pipes do build abit of pressure, can feel it.
Ive replaced the PCV as a smoke test was done and it was found to be leaking.

What would symptoms be for a faulty/failing cam follower ?

Ill have to try get some live data and report back here, not sure what correct readings i should be looking for :-/
 
audi upgrades
To be honest rather than think about symptoms of a cam follower, easiest to just check it. I was hesitant bit took me less than 30 mins although I have the easier non banjo bolt version.
 
And it is much better to get sight of it to check to rule out issues. To be honest you may as well get a backup cam, bolts and o seal in case you need to change it over. If you don't do it now, you likely will be at some point in future.
 
Hi, do you have any result since than? I have almost the same issue.when I start to accelerate I can hear a loud noise probably from the turbo as it sounds like a WRC but only for a second or two and suddenly all the power is gone,when I restart everything is back until the next acceleration.If I push only like quarter throttle it seems okay but can not push over 4000K because than the power is gone again.changed the PVC,DV,n75.It seems that until a point there is no boost at all than comes a huge overboost so the ecu or whatever shuts down to prevent damage..I'm just as desperate as you are...
 
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Well cars been into another garage for almost three weeks. Has been checked inside and out.
No issues can found. Mechanically it is fine, no problems.
Once again no faults picked up from computers plugged into it
Garage have suggested the ECU is at fault.?.?
They have tried to access/read it and they cant, its like its locked.

Ive found while googling that there was a ecu issue/s on the 2005 A4's and a recall I think was issued..

im going to ring Audi tomorrow to check if this was the case.

Is it possible for ECU to go faulty ? Is it worth getting another ECU ?

Thanks
 
Thanks for the advise so far. Not sure what diagnostic system was used. So far everything from vcds.,snap on and others have been plugged in.

So having got the car back, decided to have a good look around it.
Ecu I've checked is bone dry.
Removed rocket cover and all looks fine.
Removed cam follower and that looks fine to me, it is marked but not worn.
IMG 20151012 WA0000


What I did find tho, which I'm not sure about is that when releasing pressure in fuel pump, that there was no pressure ?
It just dribbled a bit of fuel out, no force or pressure at all?
Is this normal or is something at fault. ?

Also the low pressure fuel sensor I removed. Can this be bench tested?
Removed this as the plastic connector has a bit of play in it.

Any advise would be grand...
 
I'd change that follower. And for the fuel pressure how long had the engine been off? Had you pulled the fuse and cracked or done anything else to drop the pressure?
 
Is that follower bad? Likely to cause issues?
Car was started day before for about two minutes and then left off until next day, when I started pulling the cam follower out. Would a pressure drop/no pressure be normal? If not started/ cranked.
Didn't do anything else that would drop fuel pressure.
 
If you've taken the follower out and there is any significant wear, for the cost of the part and the damage it can cause, generally worth throwing a new one in!
 
Oh and with the car off it will generally loose some pressure. Do you have vcds?Very easy to see if the pressures are getting up no normal levels in priming etc
 
That explains having no pressure..
Ive replaced follower and fitted a genuine new fuel pressure sensor ..
No difference at all, still hits this 3k limit and nothing after that..

What would I need to look for with vcds ?
Any other pointers ?

Thanks for help and advise so far ..
 
Would it be an option to get the car on a rolling road with one of the tuners that really understands the 2.0 Tfsi ? I know its going to cost some money to do this and the comment isn't meant to sound flippant, just thinking it may be a way forward for you ?
 
I have thought about that too and no flippant taken lol , just I don't have anywhere close by to go to..
and having to have car recovered everywhere is costing a fortune now :-(
 
Is wastegate actuator stuck open?? Where about are you?Also if cat has collapsed you will get this problem.
 
Waste gate has been checked by all garages, and all have said its fine and turbo is fine ...
Based in Stoke on Trent..

Current state of play is have ordered another ecu and hoping to have that plugged in today/tomorrow and see if makes any difference :-/
 
I'm over near Matlock so if you get stuck give me a shout and we will do some logging, I've got vcds so we can figure it.
 
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Darren thanks a load for the offer pal.. :)

Have good news.. cars sorted !!! whoop whoop !!!! :yahoo:

Brought another ecu of same part number, had it decoded and boom car revs freely and drives perfect ..

Looks like a possible faulty map on my ecu causing the issue !!..

Want to say thanks again to everyone who chirped in and helped/advised ..
Got there in the end ...:respekt:
 
Hello guys. I'm having some sort of similar problem after a light front bump, on my car, a 2005 A4 2.0TFSI Quattro. I just got the car from garage where it had the front bumper painted and other bits changed. All the front had to be removed to check for damages and reinstalled.
Immediately after I got the car out I noticed a weird hissing noise coming from the engine bay when on load, especially under 3k rpm, starting with as early as 1500rpm, something that wasn't there before for certain. Also, if I let of the gas while on boost, I hear the turbo flutter. Again, something that wasn't there before.

Also, there's a sensible loss in power, especially in the low rpm. It used to be pretty brutal at around 2500rpm, but now it's just linear. Top end power seems to be fine.

The guys from the garage told me they had to remove some intercooler piping and they asked me to come back to check for any loose pipes. Is this a piping issue, or I got the diverter valve shot?
 
I'd start with checking the piping and ICs for splits or joins not seated properly, particularly if it was taken apart immediately before the problem started. Don't go replacing stuff like diverter valves until you've checked the free stuff :)
 
That's the plan. But I went on and ordered a diverter valve, just in case. If the problem is not the DV (which I really hope), I'll return it. The weird thing is that if I roll the windows down, I hear nothing wrong.
Here's how it sounds from inside, even though the phone didn't captured the sound as I hear it.
 
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