Have a 2006 b7 avant 2.0 tdi bre engine code , I find its very slow to accelerate especially in 1st and 2nd gears..boost doesn't fully kick in until 2200 rpm...

Is this just the nature of this engine?

Not throwing any codes at all, injectors tested resealed all good as is the fuel system..can't hear or see any visible boost leaks ..n 75 replaced , turbo and manifold etc all cleaned up too ,flaps wrking good.

Has anybody experienced this before?

Thanks in advance..

Boost leaks can come from where the clips join the rubber hoses on to the turbo etc. As under pressure it can cause the air to escape. If that makes sense. 

In failing that, what make was the turbo. I ask as some cheap turbos are known to fail quite early. 

Hi Steve Q thanks for your response, I take it your talking about cold side of turbo,  air intake hose, its good and secure..

The turbo is stock so unsure of brand. Once it does boost at 2300rpm its consistent and pulls hard thru all gears..this is more so in 1st or 2nd gear while trying to get going.

 

How old is the turbo? 

It was replaced by audi 4 years ago..did the timing belt last week checked turbo all is good ,

7 hours ago, marca4 said:

It was replaced by audi 4 years ago..did the timing belt last week checked turbo all is good ,

Did it start happening after timing belt change? 

If so, could the timing be out ever so slightly 

Any update on to what cured the issue as I'm having the same issue ? 

9 minutes ago, Coyney said:

Any update on to what cured the issue as I'm having the same issue ? 

Yes a map to 170bhp..was a completely different car then..I was used to a 1.9pd 130 and couldn't understand why so sluggish after the 1.9.. the map changed it.

Just now, marca4 said:

Yes a map to 170bhp..was a completely different car then..I was used to a 1.9pd 130 and couldn't understand why so sluggish after the 1.9.. the map changed it.

It's not a issue its just how they are,,

Update on the A4. Still the same, cleared all the fault codes related to MAF, MAP drove it around this week and they still haven't came back. No faults on the car from 3 different readers.

Just took it to a DPF specialist to check that and it's fine. Seems like it's regening ok so didn't want to force one. 

Boost pressure still looks fine. Everyone seems stumped ! 

Quick question if anyone can help when replacing MAF and MAP do I need to programme it to car? No options on OBD eleven to do this. 

Pulling my hair out now.

Another fault I did noticed was the SAS sensor (can't remember the code) cleared it and yet still hasn't came back. Was wondering if this could restrict power on low RPM?

Also another thing could the cruise control be at fault? Could it also be restricting the power and RPM or ESP? 

Any tips or advice much appreciated before i start stripping the entire engine out 😂

You didn't listen to what I last replied to you...your just throwing good money after bad...there's nothing wrong with the car ,,hence why everything is coming back good for you..I researched everything extensively on different forums..even spoke with a very experienced ex audi tech who told me it was just the nature of these  ,told me to stop throwing good money after bad and get it remapped to 170bhp..I did..car pulls very strong in all gears ,plenty of power...

You will need to bring it into a garage to get it done properly, preferably one with a rolling road will cost you around 250-300..

That's all that's needed 

Just search car remapping in yr area and go with a company with good reviews etc....

Hope that helps you..only solution unfortunately but it wont cause any problems to engine turbo clutch etc etc as long as you keep the upgrade below the 180bhp mark..

Yes needs the map to be written up and programmed into the car by someone experienced at what they do...you can buy the software to do yourself but avoid that and book it into a reputable company...👍

 

It's not the nature of the car . I've had it over 2 years and it's never been like this. 

You shouldn't have to hold revs at 1500rpm to pull off keep dropping it down to stay above the RPM to stop it cutting out. 

Maybe yours needed a remap but mine certainly doesn't. 

I've spoke to Auid technician and they are stumped aswell as it has no codes showing hence doing the cheaper jobs first. 

If it was always like this then I'd agree with your statement about a remap but clearly something has caused the issue hence trying to resolve it 👌

 

You didn't state this was a new problem after running it for 2 years....try injector harness so.. it runs under rocker cover and with the heat it can become hard and brittle...i got one for mine on amazon and it works fine..about an hour to fit it

Did you get a pressure checked on boost end?  Also check the n75 valve they can give problems..otherwise bring it to a good independent vag specialist..check vw forums also

On 8/19/2025 at 12:56 PM, marca4 said:

You didn't state this was a new problem after running it for 2 years....try injector harness so.. it runs under rocker cover and with the heat it can become hard and brittle...i got one for mine on amazon and it works fine..about an hour to fit it

Did you get a pressure checked on boost end?  Also check the n75 valve they can give problems..otherwise bring it to a good independent vag specialist..check vw forums also

I've checked N75 valve and all Is OK.  The injectors are performing as they should and all within tolerance on live data aswell but I will check the harness this week. 

 I've just taken it to a so called expert master technician local to me and first thing he said was all the injectors are toast and most likely need a new head. Looking at 1500 minimum. After watching the live data with him I could see the injectors are all running the same values hence questioning him. He said these engines are prone to head failures hence there is not many on the road anymore ! Now I'm no expert at all but the injectors and harness were replaced by Audi under the recall in 2013 and its only done 50k since (currently on 130k) and I find it hard to believe they can only last 50k and the head to be scrap. 

Looks like it may have to go to Audi as every so called expert has a different opinion on it. From all the forums and info I've researched I've yet to see any failed heads. 

It's definitely a fuel related issue as its struggling to start lately. I'm going to drop the fuel and replace filter one more time before it goes in to Audi just incase.

Andrew.

Have you considered the possibility of a dying battery? An old battery can show 12 volts on a multimeter, but still have such a high internal resistance that it can not reliably operate the cars electronics, leading to various transient unrelated faults without any error codes. A professional battery test that places a heavy electrical load on it should reveal any problems. If a new battery is needed it will need to be coded to the car.

It's had a new battery not so long back and I spoke to Audi as its a B7 it doesn't need coding to the car. Only later models apparently. The problem is there is no faults on car, everything I've changed hasn't resolved the issue and its becoming a money pit. 

The issue only started after a long 4 hour drive on the motorway with cruise control enabled so currently trying to shed some light on that and if it could of affected the throttle position maybe. When yoh unplug boost pressure sensor it revs fine in low rpm so it's throwing me off as it seems to be sensor issue maybe yet its been changed twice aswell as the MAF. 

 

Well that eliminates the battery from the diagnosis. I don't know what else to suggest, but wish you luck.

1 minute ago, cliffcoggin said:

Well that eliminates the battery from the diagnosis. I don't know what else to suggest, but wish you luck.

Cheers buddy. The fight continues !