1.8T - blockage.

[brummieboy]

Hi all, looking for some guidance............

my 1.8t has times when it feels very asmatic between 2200 - 3800 revs, including under full throttle. Sometimes under full-on boost its almost as if something was blocking that becomes shifted, and in return it sweeps through the rev range quickly. This happened today and a plume of dust from came from my exhaust and engulfed the car behind!

This situation is intermitent - sometimes it revs sweetly, sometimes it has no guts at all and feels like something is blocked.

Any thoughts would be much appreciated.............

[paul b]

It would be helpful if you managed to get a fault code read done with VAG-COM or similar. Without knowing of any fault codes and therefore guessing (not always wise !), I would start by fitting a new MAF (Mass Air Flow) sensor. If you change this ensure you buy a genuine one, and stear clear of the fleaBay rubbish because they are fakes and can make your car worse than it already is.

Paul

[brummieboy]

Thanks Paul b. MAF is on my list, but would this provide an intermitent problem,? I think the dust explosion out of my exhaust is a bit strange -Could that be MAF too?

[paul b]

Thanks Paul b. MAF is on my list, but would this provide an intermitent problem,? I think the dust explosion out of my exhaust is a bit strange -Could that be MAF too?

It could be.

However, if you have serious dust coming out of your exhaust on start up then that could mean that your turbo is failing.

I've heard of other stories about the 1.8T, with "oil sludging" or something. Crasher or A8 Tech would be more clued up than myself.

Fault code read... go on do it...

Paul

[brummieboy]

Thanks, i will - just need to find where - Audi wanted £115 + vat!

The dust isn't at start-up; sometimes the car feels like its not breathing properly - a blocked nose is the best analogy. Giving it some high boost sometimes shifts the blockage (not always) and the last time this happened it was daylight and i saw the car behind disappear in a cloud of dust from my exhaust. I understood a dodgy MAF resulted in poor fuel/airmixure and bad running - nothing that would result in a dust explosion. Its all a bit strange............

[a8 tech]

possible collapsed internals in the catalytic converter blocking the exhaust or blocked crank case breather

[paul b]

possible collapsed internals in the catalytic converter blocking the exhaust or blocked crank case breather

I think the cat converter part of the exhaust for my A6 was over £400 when I last looked. Ouch...

Paul

[brummieboy]

Thanks a8 tech - that pics how i feel! How would the cat issue be diagnosed?

[a8 tech]

well you would normally see the cat temperature rise and intermittent misfire due to the gas backing up but also a lack of power,As for the breather system which is far more likely,remove the pipe at the back of the rocker cover and check it gives a good old blow (o er).It sounds like a strange fault as you haven't mentioned any warning lights i would suggest this is mechanical but a fault code scan is required to eliminate any fueling issues or unmetered air

[brummieboy]

Thanks, I'll get on to it. I've no warning lights at all. I've had the engine chipped to 180bhp some months ago and at the time was told the MAF was not showing correct voltage, but told that this was only slight and shouldn't be an issue. I think the engine as a whole runs very hot, although i've replaced the thermostat and temp sensor and nothings changed.