chris_72

So I have no boost…
I started my car as usual, and I was pulling away when all the sudden I heard the turbo really start to spool hard. I immediately let off, and the BOV made the loudest hiss noise that I have ever heard from the car. So I think obviously there has to be something wrong. I don’t have a boost gauge, so I can’t say what the boost spiked to. I tried to lightly accelerate again, and the same thing happened, but all of the sudden the boost just disappeared. I think my wastegate actuator rod came loose, or my wastegate is dead. Does this sound right? I don’t have a VAG – COM, so I can’t really check it out that way…

The car is a 1997 Audi A4 1.8T Quattro 5-speed

THANKS!
Chris_72

wailshark

Did the car throw a CEL when this happened?

sonic

well if you didnt get a CEL light, its not your turbo spooling too hard. you could have a boost leak such as a hose breaking...its could also be the DV. When you say you heard the turbo spool harder, did the car go any faster then usual? if the dv is gone then the turbo may be trying to push harder to get to where the boost should be at.

whoace

Check for boost leaks. Might just be a blown off hose. Check the turbo inlet pipe as well.

chris_72

Marko_tomas13:
No CEL light. I wish I got one, because then I would know that there were some codes that might point me in the right direction.

Sonic:
I really think it was the turbo spooling hard. I cant think of anything else that would make that sound. I have a Nissan 300ZX Twin Turbo with upgraded turbos, and the Audi sounded just like it… I don’t think it’s a hose that popped off, for 2 reasons:
1. The turbo stopped making boost after the second time that I tried to drive it
2. I checked 3 hoses (turbo to that frame pipe, frame pipe to IC, IC to throttle body) and all looked good, I even went around squeezing them hoping that I might find a rip or hole. No luck.
Also, my car has a BOV installed where the DV was. I’m not a big fan of this mod, because this car is super slow and with that stupid thing blowing off every time I lift off the gas… It makes me look like “German rice”

Whoace:
I took a look at the turbo inlet pipe, and its solid too.

chris_72

Just a quick Q:
If my waste gate control tube (the little vacuum line with the electric thing, from the turbo snail to the wastegate) If that line was cut/off/worn through, would I have full boost, or would I have no boost?

DominikA6

full boost to the max. the wastegate regulates the rpm at which the inducer is spinning at. if there's nothing to regulate it, it will just keep going and building inefficent boost.

K04-S4

You should do your engine a favor and toss the BOV after you install a BPV. Your gas mileage and performance will go back up and your engine will love you again

Then you should pressure test the intake system as a visual may not always reveal a leak. Make your own intake pressure tester for $20 parts at a home hardware store. Set air comp regulator to ~10psi and connect to intake.

This is for a 2.7T but you should be able to make something of similar design for the 1.8T:

http://www.awe-tuning.com/media/pdf/...ure_tester.pdf

S4zAudihere

if you had access to a vag com you could read what ur boost pressure is like, as well as anything else, i would try and find access to one. it'll help eliminate some things to help you find what's wrong.

chris_72

KO4-S4 Thanks for the tip. I hav one of these things for my Nissan 300ZX Twin Turbo (these things are prone to boost leaks) I will give it a go...
Thanks for all the tips/help this forum has been much more helpful then VWvortex....