Name says it all. A4 Quattro 1.8T Manuel. 1998 aeb code.
I see 18 hg vac but will only boost to 4psi then sink to 2. Thought it was my boost guage. Bought new one today. Nope. Also hearing a Fast clicking / taping sound when I let off the gas 4000rpm+. Sound coming from exhaust side of turbo. Cant see any visable leaks/holes in charge tubes or IC. No codes eather. (sept my test pipe code). Any idea?

 

Sounds like the waste gate may be shot.

 

Buddy at the shop told me to pull the vac hose off the waste gate to test. Is this true? if I dont boost is it the waste gate?

 

Revd the motor from engine bay. I can see the actuator move. Looks to be working correctly.Starting to think its the DV. Its got 118k origional miles. Any other ideas?

 

I'm having pretty much the exact same problem dude. I got no boost whatsoever and am basically stumped.

 

I'm telling you, I just had the same issue with my turbo on my 99 A4 1.8T. Low boost and a high buzzing/ clicking noise under deacceleration; it's definitely a bad wastegate valve. To check this you can use a coat hanger to pull on the actuator rod, creating tension, and manually reving the engine on the throttle body to see if the noise goes away. I am almost 100% this is your problem. I had the whole front clip of my car removed ready to install a timing belt tensioneranticipating that was the problemuntil I was directed to the wastgate.Unfortuantely you have to replace the turbo; I ended up buying a used low mileage passat turbo for $200....although many others would encourage this time as an excuse to upgrade to a K04!

 

Will run the test in a cuple minits. Unfortunitly I cant aford a Ko4 upgrade. If I got my facts straight. I would need: Exhaust manafold, downpipe, New IC, Piping, And a chip. Thats a big bill to foot when im paying for a wedding/ new appartment. Saw a cuple Ebay turbos claming to be Ko3s.http://cgi.ebay.com/ebaymotors/K03-T...QQcmdZViewItem

Says 1/2 inch bigger compresser then stock. Is this true?

 

I just ran the test, Coat hanger wraped around the wastgate bar. The rattling didnt stop. Altho on spool up. My turbo was much more audible. Even had a lounder blow off. ( more boost). SO now im stumped. Ima run to the stealer an grab an 710n. See if that fixes it. If not. I guess new turbo time.

 

Well I searched the forum and found several posts relating to this problem/ issue/ sound. Sounds like its' definitely turbo related problem. If the sound is only apparent on deceleration than it's most likely your wastegate valve just flapping around not sealing nor holding boost. I'm assuming a boost test would predict if a bad wastegate would be bleading off boost; that was my exact problem. Its' a shame you have to replace a whole turbo for a valve, now if it was a bad actuator you could just replace that component, but thewastegate valve itself is inbedded into thehousing on the exhaust side of the turbo.Whatever you do..DO NOT waste your money on an ebay K03 replica/ replacement; it will not last.

p.s. after a cool down,if you can wiggle that actuator rod theslighest bit, than that will tell you the valve is shot = new turbo time.

 

im facing the same issue. i hear a rattle noise almost thought it was my manifold or something. i will have to check this, but where is the wastegate? if im looking at the engine from the top, to the left.. turbo, and then the waste gate is where?