loss of power around 60 and hesitation on 2.5tdi Quattro

**mark shutt** · 09-07-2012,07:01 AM

got an ongoing problem with my Audi, thought I fixed this when I fitted a new throttle body a few months ago but now the engine light keeps popping on again, went off before a 150 mile round trip yesterday but the car kept loosing power most notibly up hill around 60mph in 6th gear, there was just nothing

any suggestions? last time we put her on VAG-COM it was showing a temperature sensor fault but we cleared it and it was fine for about a month so left it alone..

Mark.

**SWARCUP** · 09-07-2012,06:57 PM

Originally Posted by mark shutt

got an ongoing problem with my Audi, thought I fixed this when I fitted a new throttle body a few months ago but now the engine light keeps popping on again, went off before a 150 mile round trip yesterday but the car kept loosing power most notibly up hill around 60mph in 6th gear, there was just nothing

any suggestions? last time we put her on VAG-COM it was showing a temperature sensor fault but we cleared it and it was fine for about a month so left it alone..

Mark.

When you say a loss of power, is it a short hesitation say maybe a second long like its stauttering, mine was doing this as you describe uphill with the right foot down. I fitted a blanking plate to the egr valve and it cured it. I suspect that the egr valve needed a clean or possibly replacing.

**mark shutt** · 09-07-2012,07:12 PM

sometimes I get hesitation around 70 if I floor it, but this happens lower don the rev range especially going up hill, for 5 seconds maybe more there is absolutely no responce like it's restricted or in limp mode. I've been advised it "could" be my air flow metre..

what's the blanking plate trick, is this some kind of mod?

Mark.

**SWARCUP** · 10-07-2012,10:04 PM

The blanking plate blocks the flow of recycled gassses back through the engine which i dont believe to be the best for the engine as they can leave deposites of black oily tar like substance in the pipework. A blanking plate effectively seals the pipe and stops this and takes the egr valve out of use so if it is done in it will now stop affecting the performance. Ther is a thread on audisport.net in the diesel section where i have uploaded piccys etc of where the plate goes, however at the moment i cant access the web page so i will post a link later for you. Removing the egr will give you slightly better throttle responce also

In respect to the maf, unplug the electrical connector from it and go for a drive, if it stops doing the hesitation then it is the maf, the ecu will substitute a stored map for the airflow when it doesnt recieve live data so thats how this trick works, if still the same probably not the maf, This will generate a stored code when you next have the codes read just so you know. Next step will be to have the codes read.

**pauldazzle** · 11-07-2012,11:14 AM

Replace the Coolant Temp Sensor. It's one of the most common causes of running problems on VAG cars. THE CTS has 2 outputs 1 to the gauge & the other to the ECU if the ECU is getting the wrong temp info it won't fuel correctly. Unfortunately unplugging the MAF for diagnosis doesn't usually work on VAG diesels. Works fine on the petrol engines though.

**mark shutt** · 11-07-2012,05:15 PM

Originally Posted by pauldazzle

Replace the Coolant Temp Sensor. It's one of the most common causes of running problems on VAG cars. THE CTS has 2 outputs 1 to the gauge & the other to the ECU if the ECU is getting the wrong temp info it won't fuel correctly. Unfortunately unplugging the MAF for diagnosis doesn't usually work on VAG diesels. Works fine on the petrol engines though.

just replaced this so will see how it goes tomorrow on the way to work!

Thanks, Mark.

**mark shutt** · 27-08-2012,07:49 AM

well the coolant temp switch kinda fixed the problem, or so I thought until I just done a 600 mile round trip and after about an hour of motorway driving the problem comes back, this only happens going up hill!! it doesn't matter whether I'm in 4th or 6th the car just dies anywhere between 60 and 80 mph for a few moments.

so next things to look at I guess is MAF and EGR valve? is there anyway of testing these with a multimeter?

Mark.

**SWARCUP** · 28-08-2012,07:35 PM

Originally Posted by mark shutt

well the coolant temp switch kinda fixed the problem, or so I thought until I just done a 600 mile round trip and after about an hour of motorway driving the problem comes back, this only happens going up hill!! it doesn't matter whether I'm in 4th or 6th the car just dies anywhere between 60 and 80 mph for a few moments.

so next things to look at I guess is MAF and EGR valve? is there anyway of testing these with a multimeter?

Mark.

The egr doesnt have an electrical connection it works on sucktion i think,The easiest way to check if it is the egr valve is to blank it off, i had this same problem and cured it by chance when i fitted a blanking plate. see this thread as there is a photo and explanation of where it goes HELP!! What is this noise?

**simonrk57** · 28-08-2012,07:45 PM

I have this on my 2.0tdi B7....

Its a pain in the a$$.... I cleaned my EGR and it seemed ok for a while but it was SO clogged up, I couldn't get it properly clean.

I notice mine is most common after extended periods at a particular speed I.e 70mph for 20 mins on the motorway. It's when I then increase power that it isn't there.

If I'm blasting around country lanes through the gears, it doesn't happen :/.

Most annoying!

**abyrne153** · 28-08-2012,09:57 PM

Check also for sticking vanes in the turbo. You can check the actuator arm for signs of sticking and if you think this is the problem then you could try the Mr Muscle treatment which is well documented on this forum. I did mine and it made a big difference as did blanking off the EGR.