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Matt
Matt, Mechanical Engineer
Category: Audi
Satisfied Customers: 21864
Experience:  BEng hons Mech engineering, in auto industry 22 years
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hello my 2002 audi a4 130 bhp is goin on and of power when

Customer Question

hello my 2002 audi a4 130 bhp is goin on and of power when i give the car thottil nice and esey it has power but when i give the thottil hand it has no power?????? and 1 day when i was driving and i hit boos i heard a big pop and have no boost now i looked at all the pipes and they lok ok no leaks would my intercooler of blow out by any chance
Submitted: 4 years ago.
Category: Audi
Expert:  Matt replied 4 years ago.
Hello

I'm assuming this is the turbo deisel so I'd first check all the high pressure hoses post turbo/s for any split hoses or cracked metal pipes, also check the ends of the intercooler as its not unheard of to pop the end caps off under high boost.

If this is OK then check the small vacuum lines to the turbo and its connected control solenoid on the bulkhead, any cracks or leaks can give turbo issues

Also have a feel around with your bare hands with the engine running to see if you can feel any escaping gas under your touch, while your assistant revs up the engine

Another method is to use a soap and water solution sprayed onto any suspect areas - if there's a leak it'll bubble up with the engine running

If this is OK then remove the high pressure intake hose after the turbo and have a feel of the turbine wheel - there should be no play radially at all - but a little bit of axial / end to end float is normal

If this is OK then check for air leaks after the mass airflow meter - The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane around each joint in turn. If the engine rev's up you've found your leak.

Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.