Newbie with a new car and a problem!

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Willf

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Hi all - I am nwew to this forum (obviously), so apologies in advance if I am posting in the wrong forum etc!

I'm Will from S Wales who is the new proud(ish) owner of a Tdi Sport Estate.

Its a shame that my first post is a plee for help - but needs must!

I bought the car from an auction (eek!) on Friday - FASH, 105k, AWX tdi lump etc etc

I made it 4 miles before I realised that the turbo wasnt really doing a great deal - and there was a severe lack of power.

I also noticed that I was throwing out a significant amount of black smoke and the car would really rev passed 2.5k

When I can to a junction after this joy - the car was idling very lumpy and refused to rev at all! (Luckily this cleared after I turned it off and back on)

I had it on Audi's diagnostic computer for a few hours on Saturday (with a mate who works there) and the only teal issue we could see was that the AMM was doing some strange readings. I subsequently bought a new one and it was still the same!

So to sum up - it boosts OK for a small while when in 1st gear, then it pretty much has no power and after a while refuses to rev.

Have tested the EGR valve (and AMM) but was wondering if theer are any maual checks?

I have also checked fro boost leaks - there is one potential from the intercooler, but it shouldnt warrent such a HUGE lack of power surely?

Help!
 
Hi Will, welcome to ASN. Have a read through faqs threads at top of the page, lots of information in there. Sure someone will be along to advise you shortly. Any pics? Enjoy the forum. :)
 
Check your vac lines too it sounds like its going in to limp mode for some reason turning it off and back on brings it out of limp mode

Could also be sticking turbo vanes
 
Thanks for the quick responses - I will have a look through and see what's what!
 
Intercooler pipes? My dads golf TDI had the same problem, intercooler pipe was split.
 
How can the N75 be diagnosed? i am guessing you have a mate look under the bonnet whilst I load up the engine?

I have checked for leaks on the inlet side and have noticed signs of leaking - but not too excessive. I would expect there to be be a clear 'whooshing' sound if I was leaking that much boost!?
 
You will get a whoosh if its only leaking a bit well I did with a cracked intercooler although I could still drive it and never went in to limp mode

When it goes in to limp mode it should throw a code as to why
 
Exactly - I am thinking its more of a mechanical issue, rather than electrical and nothing on the dash suggests its going into limp mode?

There is some oil spray around the intercooler, but it would still try to boost I would guess.... unless its got a massive hole!
 
you dont get anything on the dash when it goes in to limp home mode it will only show you on a diagnostic machine

i had a small crack on my intercooler which developed to a huge crack and was loosing a lot of air but it was still boosting and not going in to limp home mode it drove fine until i replaced the intercooler
 
Thanks Stu - thats really useful to know, as I was thinking about changing my i/c tonight before I get it back on the laptop for further diagnosis.

I didnt realise that the onbaord computer was so ignorant! lol. In limp mode then - it just feels underpowered and wont rev?
 
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yeah thats about right struggles to get past 2k

if you drive it get it to limp mode pull over swith off then back on then its all back thats definitely limp mode

i will warn you now the IC is a pig of a job you have to remove the bumper to get to it! but if you have one and can do it i would change it so you know its right

you never know it could be going in to limp mode because of the leak it depends how much pressure your loosing as you could be getting under boost
 
Yeah thats true - I will deffo replace it, I just want to drive it to my lock up (use of ramp) to do it. The lock up is 5 miles away, and as it stands that would take about an hour with the car in its current state!

I think then (based on what youre saying) that the car is simply going into limp mode as soon as it comes on boost in 1st gear and thats the reason I have no power/black smoke etc in subsequent gears, rather than catastrophic mechanical failure of something!
 
to me it sounds like one of two things underboost (leaking IC) or overboost (sticking vanes) i would sort the IC first and see how it goes

although i had a rather large leak and it never went in to limp home mode!

what is your location? is there no one close by with VCDS who can check boost pressure for ya?
 
In S Wales - a good mate of mine has the kit - we had a really quick look on the weekend, hopefully get a decent look tonight.

It was showing zero boost in all gears though - I remember that much. Although it did boost once (in first gear) and it was around 1 bar.
 
I think they boost up to 2 bar to start with then come down a bit
 
Ok - spent a few more hours on this over the last few days - replaced some boost pipe seals, hooked it up to VCDS for most of that time also cleaned (then blocked off) the EGR valve which made a difference in that it now boosts in firat and second OK, but then you have to 'feather' the throttle to maintain the boost or it just goes flat - this is true of all other gears and I am putting down to the fact the engine is under much more load...

Swapped the AMM for a new Genuine part and that made no difference! (so sent that back!) and have now cleared all the fault codes and it seems not to be storing any now...

Next steps are to change the fuel filter (I was going to anyway) and disconnect the CAT to see if thats blocked...

Any other suggestions/observations!?
 
did you sort the boost leak out?

I find it really odd that its not throwing up a error code!

could be sticking vanes on the turbo causing over boost
 
I could only feel boost in 1st gear until I did the Mr Muscle fix, & it made a huge difference. I didn't have any codes on VCDS either so it's well worth a go.
 
Yeah - the turbo is also on the list, I loosened the cat and took it for a spin, but its still the same - kept coming to a standstill again, and refusing to rev above idle speed. I am guessing that it will have some codes stored now.

Also swapped the fuel filter so its not that either - so if the Vagcom doesnt show anything - its Mr Muscle time I think!
 
When running vcds go in to measuring blocks and check the turbo requested against actual if actual stays high when requested is low that would indicate over boost which will be sticking vanes
 
Will do - cheers Stu.

On another note - it seems that Mr Muscle oven foam does not exist in Wales! lol May have to get it imported from England!

Unless there are any other brands/foam I can use?!!
 
Cheers - a 50 mile round trip may be on the cards then! lol
 
Update - I did the oven cleaner thang (albeit without the help of Mr Muscle) and also blanked off the EGR and its still the same!

Actually its a bit worse, but that may be because I was annoyed and purposely flooring it and it kept coming to a halt - not allowing me to rev it at all!!
ARRRGH!
 
So what fault codes do you have? If it's going into limp it'll have thrown a code.
 
Cant be going into limp mode, as the only one it has stored is the silly engine mount code!

Its starting to annoy me now - as I keep changing my mind whether its a mechanical or electrical issue... I guess it still could be a duff turbo - I will rip the exhaust off and check the impellor on the exh side, as the other side seemed fine (no play etc) over the next few days...anyone recommend any decent turbo reconditioners??

Tried another N75 last night, just cos I could and that made no difference!
 
Have you checked to see if the VNT turbo actuator arm is moving correctly?
 
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It's looking like you have a mechanical problem. Have you done any logging with vcds?
 
I have done some -I did notice the AFM seems to be playing up - or rather its showing 450-500mg when the optimum is 250 at idle. But its not the sensor - so I guess it could be wiring - or something else causing the odd readings!
 
The AFM plays a crucial part in how the engine performs so I would try a known good AFM. I've known new AFM's to be faulty straight out of the box, even genuine VAG. Aftermarket AFM's are notoriously bad so steer clear of those. An AFM wiring issue should show up on vcds as inplausible or intermittent signal so I doubt that's where the problem is.
 
I bought a new genuine one and that didnt do anything - so I tried another new genuine one (feriend works at Capital Audi) and neither did that!

So I am pretty sure the sensor itself is ok!
 
Its fixed!!!! After all the head scratching and time on Vagcom etc - I noticed that the induction pipe was collapsing when the engine was under load...

The reason teh AFM was having kittens was the fact the air filter was blocked!!!

£11 later and she's running spot on!

Thanks all for the help and suggestions!
 
I think a serious service is in need on that car bud.
If it's got to the point where the airfilter is that blocked. Someone hasn't kept up the servicing.
If they haven't done the air filter, chances are you'll open up a shed load of power when you replace the fuel filter.
 
Already WAY ahead of you - as soon as we unearthed this - I bought (all genuine)
Pollen, oil, air and fuel filters
Oil (obviously)

Really odd that it has FASH too - it looks like the filter had gotten damp though and the glue had congealed and blocked it!

She runs spot on and is quiet as a mouse (ish!)
 
My car has FASH (verified by Audi) & the air & fuel filters were both minging when I checked them a few days after buying the car . The garage I use in Cardiff reckon they see this all the time with cars that have had main dealer servicing.
 
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