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Audi 4.2 v8 engine problem
Cluelesstom - 18/10/19 at 10:53 AM

Hi guys, hopefully someone knows something about this engine...
I recently put this engine back in and it’s developed a intake flap noise, I haven’t altered the arm or disturbed anything,
When on idle the vacuum is actuating and causing a tapping noise, if I then move the arm the noise goes. Any other ideas? Would other problems cause this noise?
Thanks.


nick205 - 18/10/19 at 11:31 AM

I don't know the engine, but have you checked wiring and hoses etc. are correct?

Could a wiring error or vacuum leak cause the problem.

I'm guessing if you removed and refitted the engine you must have disconnected and reconnect a lot of things.


pewe - 18/10/19 at 11:33 AM

Sounds like there's a damping issue on the vacuum feed causing the valve to flutter.
I had a similar problem on a supercharged engine where the by-pass valve was clattering.
Solution was to fit a roll-up ciggie filter in the vacuum line to modulate it.
Not saying that's your solution but research in that direction may prove fruitful.
Maybe there's a filter missing or worn out?
Is there a blow-off valve in the system which is past its sell-by date?
I do know on other VW/Audi turbo cars a cheappo plastic BOV is used which probably has a limited life or could just be dirty internally and not functioning properly.
HTH.
Cheers, Pewe10


Cluelesstom - 18/10/19 at 11:39 AM

Right, just had a play literally taking everything off related to this hose, then found a little solenoid on the vacation line, unplugged and reconnected, seems to work fine now... only if every problem was this simple..
Sorry guys, maybe a heads up for someone in the near future 😁.
Thanks for your replies