a4 problem air delivery

**richard3009** · 10-07-2008,02:59 PM

there is a solenoid mounted in fresh air at the front of the engine with some thin pipes going to it, if i turn the ignition on without starting the engine this rattles away like a little ticking machine gun.

Could this be my culprit

**Crasher** · 10-07-2008,03:14 PM

It is right down at the front of the engine in front of the turbo on a bracket. The valve is tested using something like VAG-COM in Output Tests 10 where it should click and you test the passage of air through the valve using a hand vacuum pump. Without VAG-COM all you can do is check the vacuum routing and measure the resistance of the valve which should be between 14 and 20 Ω.

**richard3009** · 10-07-2008,03:18 PM

there is a solenoid mounted on a bracket in fresh air at the front of the engine with some thin pipes going to it, if i turn the ignition on without starting the engine this rattles away like a little ticking machine gun.

If this solenoid was faulty could it cause such a loss in power and smoke from the exhaust

Could this be my culprit

**Crasher** · 10-07-2008,04:09 PM

If it was faulty, yes it would cause those problems but if it is rattling away it doesn’t sound like it is faulty.

**richard3009** · 10-07-2008,04:15 PM

its normal for it to be ticking away sounding like an insecticutor then

**Crasher** · 10-07-2008,05:31 PM

On some software levels they will tick with the ignition on and the engine not running as they would if the engine was running.

**richard3009** · 10-07-2008,10:26 PM

had a good look at the intercooler circuit from the turbo through to the manifold nothing obvious, and all the small pipes seem to be in order , however the rigid plastic pipe (aprox 20mm in size) that comes from a circular thing on the rocker box cover and then drops deep into the engine has a split in it just behind the jubilee clip, is this anything to do with the boost circuit?

**Crasher** · 10-07-2008,11:48 PM

That is the oil breather hose from the crankcase pressure regulating valve. It being split will allow in a lot of unmetered (and unfiltered) air and seriously upset the running of the engine. You should replace this before doing anything else. The part number should be 028 103 493 AF and it costs £12.70 from Audi but check before ordering.

**richard3009** · 11-07-2008,09:24 AM

Looks like its an absolute sod to fit, goes deep into the center of the engine, where does it go to and how is it retained

**Crasher** · 11-07-2008,01:33 PM

Which side do you mean, the one going down to thee turbo or the one going down the other (left hand) side of the engine? If it is the side down the left, that is the wrong part number I gave you.