Nope, only for things the ECU thinks could damage the engine. It'd be pretty ridiculous otherwise. "Oh, your rear O2 sensor's not working right. Limp home mode activate!" - stupid!

 

Ah, so even though the DV is fully closed due to the internal spring and the lack of vacuum, no boost is occuring at all, as the pressure is escaping right out the broken manifold hose with the fuel mixture running quite rich, right?

Also, must this hose be of a specific diameter? OK to pick up at a big box store such as Autozone? Or, should I be looking at specific metric sizing and specifications unique to Euro cars?

 

Pressure is pressure and it will equalize. A great difference between stock and replacement diameter could cause a delay in DV response but in order for it to matter the hose would have to be huge. That being said, for ease of fitment just get line as close to stock size as possible - autozone will be able to take care of you.

 

Looking at the pic, I would just snip off a bit of the frayed end and gently fit it back over the other end. Those little hoses get incredibly brittle though, so you may end up breaking it again in the process, but maybe not. Best case, a free, quick fix. Worst case, you do in fact have to replace the hose. Good luck finding a replacement locally though. I never was able to when I had a rash of crumbling vac lines in my B5.

 

Thanks for replies, but just so I understand what's going on - Is all the pressure that would otherwise be generated by the turbo into the manifold being lost out that hose? In other words, is that little hose from the manifold to the solenoid (N249) subject to both the full brunt of the boost pressure as well as the vacuum after the throttle body closes?

 

You just buy rubber or silicone hose by the foot to replace it.

 

Yeah the exact lines can be tough to find. You can order specific I.D. lines from www.bakerprecision.com by the foot if you're so inclined, or if you're purely about function you could use fuel line if needed - it'll hold up to boost pressure easily and it's well under $1 per foot at a parts store. If nothing else, it'd get you through until your vacuum line of choice arrived, or indefinitely if you're happy with it.

 

Exactly. If you can find it.

 

You can buy pretty much any kind of rubber hose from the parts store. Fuel line hose, even heater hose.

That previous fix probably failed because it wasn't clamped.