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Hey guys,

I have searched and searched for an answer and I am really struggling so thought Id post a question with symptoms and hopefully someone can help me out without shouting out use the search function :)

Ive got a 1996 RS4 auto on 160k, stock a rock bar turbo timer, boost guage and turbo smart boost tee set to 7psi.. Ive never had any problems with it and has always run like a dream, apart from a cold start squeal which im assuming is either power steering belt or main fan bearing

car has been recently serviced with plugs, oil, filters etc.. coils look fresh and no signs or arching or deteriation

over the last week the car has developed a whine or flutter when on boost, sounds almost like heavy induction whistle but with a stock air box and paper filter I have been a little dubious, then yesterday whilst driving over the parent in laws it started playing up.. first thing was revving up high, it usually changes gears around the 3000rpm mark on a gentle run but I was up at 4 - 4.5k and not going anywhere.. this is my first Auto boxed car and it felt like the typical clutch is going in a manual slip. it played games all the way home with over revving and not really going anywhere

so jumped on the search function and started looking at gear box slipping faults and the like.. checked gear box oil and its at a nice level and still a lovely colour of pink

Then on the drive home... it got much worse, then noticed that at 2500rpm where the turbo is usually about to kick in I have no boost its still in vaccum.. I dont get up to 0 psi until about 4500 and the car is still not going anywhere, unable to hold gears and generally being a dick

jumped on peninsula link and was able to keep at 75kph at 4000rpm which most of the holden drivers were loving

so up nice and early this morning, had another long search about boost leaks and turbos etc went out and checked all turbo hoses, and vaccum hoses, have replaced a few that looked a little suspect and still no change. one of the inlet rubbers had a slight oily residue to it though

so the question is, am I looking at a blown turbo or a f**ked gearbox, my mind is leaning towards turbo as if the gearbox was gone id still be hitting boost? but as you can understand I dont want to go spanking out lots of money just for the sake of it.

any help would be much loved, the car is my family wagon and used everyday for back and forth to work

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Had trouble with a mates rs4s the other week was a complete stocky and was making no boost "this is how we bought the car at a good price" , we hedged the bets that the turbos exhaust wheel had died , sure enough upon removing turbo the rear wheel was none existent , turbo replaced cars awsome ,

f**ksticks, looks like ill be getting grubby tomorrow and taking the turbo off to have a big look around.. then trying to find the funds to have it rebuilt - any ideas of how much I'd be looking at for a rebuild?

wow $700+ bucks! this could be totally devistating, just been reading about high flows, not sure that I would benifit, not really a car I want to be spending money on power mods - its pretty quick as it is and im pretty sure once I start to modify I wont stop

wow $700+ bucks! this could be totally devistating, just been reading about high flows, not sure that I would benifit, not really a car I want to be spending money on power mods - its pretty quick as it is and im pretty sure once I start to modify I wont stop

You could buy a second hand stocker for about $300 but it may not last either so best to get hypergear to rebuild yours (if indeed it turns out to be the turbo).

yeah if im stripping it all down id rather the piece of mind that its not going to fail on me again, specially with a few long road trips planned for 2014 (melbourne to byron and a tassie trip too)

Yep, do it once and do it properly! A rebuild is the way to go, and if you choose high-flow, it won't hurt to have the extra potential available for later. (Remember, it's always good to have options.)

If you can spin the spanners, you should have the old turbo off in a few hours. It's a bit of a tight fit and will take some manoeuvring, but you can get the turbo out without removing too much of the bits in and around it.

I wouldn't jump to conclusions about the turbo. If there is any in-and-out shaft play, or theres grinding sounds when you turn the shaft, or excessive up or down shaft play, then yes it may be time to get a rebuild or upgraded high flow.

I just replaced mine with a hypergear high flow today actually. The original lasted 125k kms (still operational, just worn).

However the symptoms youre describing dont seem to match a blown/worn turbo. Are you taking a vacuum reading from the manifold? You should be able to get to 0 vac any time you open the throttle.

Boost gauge is showing -20psi on throttle. Only gets to about 0 at about 4k usually shows 0 at about 1700 and rises above when on boost at about 2400

Most thing seem to post to turbo. But could be anything. This is my first auto. First turbo even first car that's had an ECU

Unless there is some massive restriction in the intake, when you open the throttle the manifold should fill to 0 vac (essentially opening it to atmosphere) regardless of the functionality of the turbo. Something doesn't sound right.

totally blowing my mind this is - just read about the paper clip fault code read out - will do that when i get home from work and see what it throws at me - hopefully the ecu throws out some sort of code that can help me out before I start tearing it all apart :)

Cool, but double check whether jumping contacts like that is safe (who knows what happens if you short the wrong ones)

A usb consult interface is a good investment, and not too pricey. Checking the codes is a good start, but the ability to also monitor and log the various sensors on a drive is extremely helpful in establishing patterns of anomalous behaviour. Good for tracking down odd problems.

My auto gearbox was playing up once. Turns out the TPS sensor was causing the malfunction (the auto needs throttle % for shift points etc), so thats why I say be careful about jumping to conclusions.

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cheers dude - after reading about the ecu fault codes I noticed the TPS sensor too - I do hope that its just a nice simple fix

although Ive not had a car like this before im quite mechanically and electronically minded so always very careful.. will look at picking up a consult cable if I dont get anything back from the fault codes

So yesterday got home from work and did the paperclip fault test... 5 5 meaning all is well.

Feck time to investigate the turbo.. finished that this morning and inlet has some in and out play as does the exhaust wheel.. when taking the turbo off I didnt drop a spot of oil. I was expecting to get filthy.

How much play is acceptable ?

In my experience the ecu fault codes are very likely to not be helpful, as you have discovered! The inlet and exhaust wheel would have the exact same movement as they are on the same shaft, if they move differently to each other you have a huge problem! To measure play you need a dial indicator, or at a stretch some vernier calipers, the finger isn't that accurate! Ring a turbo place to confirm allowable movement, can't remember at the moment, but it's not much.

So yesterday got home from work and did the paperclip fault test... 5 5 meaning all is well.

Feck time to investigate the turbo.. finished that this morning and inlet has some in and out play as does the exhaust wheel.. when taking the turbo off I didnt drop a spot of oil. I was expecting to get filthy.

How much play is acceptable ?

Can you hear the wheel scraping against anything in the turbo, or does the rotation of the shaft feel grainy etc?

Its possible your turbo is just worn, which is normal and happens to all turbos. I still cant see it causing the symptoms you mentioned.

No scraping. The exhaust doesn't move as freely as the inlet but still spins freely.

Worth me popping it into somewhere like hyper gear for a check up now that its all off anyway?

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