my car is having its dump valve replaced tomorrow so hopefully i will get back my lost power and be able to actually feel the turbo kick in again,i have now noticed another problem though,when the car is started from cold it is a pig to drive although it does fire straight up with no problems,when you first pull away it cuts out and seems to missfire and runs rough for about 1/4 of a mile and then all is fine again.

is there any way that this can also be put down to the dump valve or is this going to turn out to have all been nothing to do with the dump valve after all.

any other suggestions.

Have you checked if there are any fault codes logged? And have you ruled out a faulty coilpack? I don't see why a faulty DV would cause a misfire.

The 17705 fault can cause rough cold running and this can be caused by a faulty DV,

The 17705 fault can cause rough cold running and this can be caused by a faulty DV,

I should have known that. But I did remember that the pressure hose from the turbocharger to the charge air cooler is also a possible suspect when investigating irregular cold running - which is why I ordered a modified one (PN 06A 145 790C -

Have you checked if there are any fault codes logged? And have you ruled out a faulty coilpack? I don't see why a faulty DV would cause a misfire.

it is going to be looked at tomorrow so i will get them to check for any fault codes:)

that uprated pressure hose sounds like a good idea as well even if its only for piece of mind;).

not impressed:thumbdwn:have now had dv replaced and i have not got back my lost power and if anything it feels even slower.it just feels totally flat and you can barely feel the turbo at all,although you can hear it spinning up ok.

there were no fault codes showing but he said that the old dv was definately knackered.

with no fault codes showing where do i go from here.he said if it is no better to take it back but what will be his next move:confused:

If the turbo is spinning up but giving no boost that would suggest a pipe has come off from the turbo to the engine (not engine to turbo), or that the turbo is on it's way out IMHO.

I may of course be incoreect.

perhaps i was exaggerating by saying that you cant feel the turbo because you can feel it but there just isnt the kick in the back that i could feel 2 weeks ago when i first got it and it just feels gutless over about 3500 revs and takes forever to rev,whereas before it was spinning up really quickly.

whatever has happened to it happened instantly and not gradually because it was fine last monday morning but something didnt feel right when i then drove it later that night.

an example is that before when you booted it in 2nd from 1k revs,when the turbo started to spin up at around 2k you would feel a nice kick and a bit of torque steer whereas now it just builds revs with only a slight feel of a step up in power.

Could try the MAF, try disconnecting it first to see if there is any improvement.

Yeah, sounds a bit like MAF to me too. Symptoms tend to be that you have gradual power loss over time, as crap gets baked onto the sensor element in the MAF, and it's sensitivity gets worse.

MAF reads the airflow over a thin piece of wire. Resistance through the wire is measured, so the more air, the more the wire is cooled, and the lower the resistance - the ECU knows a bit more about how much fuel to deliver based on the airflow.

WHen my MAF went on my 1.8T Audi, it felt very slow to pick up power, and it felt like the power was all delivered in the higher rev band. Some people say that classic MAF symptoms are that there's no power above 4000 revs. With mine it just felt very slow to pick up.

Some people take their MAF out and clean it with an alcohol-based cleaner (some people use CD cleaner, others use circuit-board cleaner, others spend the time to try and find Isopropyl Alcohol (IPA)). I tried this on my old MAF and it made no difference, but that was a 1999 model MAF and they have changed since. Many people report that cleaning it has made a big difference.

Everything I have said here is obviously all "MAF MAF MAF", but don't let that close your mind to other causes.

Rgds,

Ben

IPA is available from maplin as either a large can or a spray.

www.maplin.co.uk

Do a search there for IPA. Failing that video / cassette head cleaner is almost totally composed of IPA anyway and should still be easy to get hold of.

I tried this on my old MAF and it made no difference, but that was a 1999 model MAF and they have changed since. Many people report that cleaning it has made a big difference.

I tried cleaning mine on Monday, but it made no difference :-( It was replaced last year by a dealer, but with a re-con unit....

Has the new one made a difference, and did your symptoms seem similar to those being described in this thread?

(when the car is started from cold it is a pig to drive although it does fire straight up with no problems,when you first pull away it cuts out and seems to missfire and runs rough for about 1/4 of a mile and then all is fine again)

BK1, cleaning made a difference on a relatives car.

Also changing air filters early also makes a huge difference.

To clean it take the MAF out, spray a bit of IPA onto the grill area and the wire area.

Put it in a food bag and put in a smallish amount of IPA then seal the bag and holding the MAF give it a really good, but not to hard, shake so the IPA gets a chance to penetrate the crud and lift it off.

Take the MAF out, give the wire a spray with some clean IPA and then leave it somewhere for the IPA to evaporate and the thing to dry off. You can reinstall it then, however I would strongly recommend putting in a new air filter at the same time you do this to help stop the crud building up again so quickly.

Obviously this information is taken entirely at your own risk and any damage you may do is down to you. etc etc.

well one good thing is that ipa is no problem to get hold of as i work with it and we keep it in 25ltr barrels:thumbup:

i know for a fact that the filter is also over a year old as well because it wasnt changed on the service that i had when i bought it so that is a good excuse for a pipercross;).

then again though ive only had the bloody thing 2 weeks so why should i be the one to try and sort it,thats what the warranty is for:D

i will give the main dealer another chance i think before i start exploring other avenues.

cheers lads.

then again though it wouldnt hurt to disconnect the maf and give it a quick try just to see if it improves matters because at least i can try and get a new one out of the dealers if it is indeed at fault.

one thing that i have just thought of is that if it was indeed the maf that was playing up,would it not have logged a fault code.

Depends I would guess, but you would need to have that read off Using VAG-COM or get a dealer etc to do it.

Depends I would guess, but you would need to have that read off Using VAG-COM or get a dealer etc to do it.

according to the dealer no fault code was showing:confused:

Give it a clean, if it is the MAF it won't make the performance worse.*

*Done at your own risk of course.

am i correct in that the maf is inside the pipework coming off the airbox.if so i tried disconnecting it and other than the traction control light staying on there was no change in performance,if anything it was slower.

did i disconnect the correct bit:confused:.

A little cable that goes into a thingyamy whatsit right next to the airbox. One end of the thingy into the pipe the other end into the airbox?

Thats the MAF.

Take it out and give it a clean.

well the dealers have had the car in today as changing the dv did not cure the problems.

they have just phoned to say that they have replaced the maf and that should cure it.does the maf cause cold running problems.

The MAF can cause a multitude of running problems, which is probably why the dealer did it first. Did you get it done under warrenty?

yep was done under warranty which is just as well as i would think that a new maf is going to be a lot of money:D

well hopefully that will have sorted it but i suppose i only have the boost control valve and the tip to get done and that will be all of the potential problem areas sorted under warranty:rofl:

I think it could be the air flow meter causing it to run slow, mine did the same but the maf according to the dealer was fine, not happy with that i went to an independant and found maf was running low voltage,he replaced it and the went like stink.

cleaning yours may stort term be fine but your always better replacing them

P.s the dealer refused to warranty it even after 7 visits with problems and a print out from other garage, JUST BUY ONE