ArthurKing

Hi all. Long time lurker, first time poster. Hope you don't mind the long post -- I need help.

I have a 91' 200 20v. Kept under covers until 01' in heated garage; driven since 02'. Has about 110k. Been learning about car for last 4 years - love it.

Have seen a slow decline in reported boost pressure. In 02', was at 1.4bar max. Each year, drop a little more. As of this spring, NEVER goes above 1.0, which effectively means I no longer even have a turbocharged engine. Very disappointing. (This is main concern of post)

History:

Car had been stalling following hard acceleration and then putting in clutch or coming to a stop. Read boards, decided issue was bad turbo bypass valve. Replaced this in 2003 (through Audi dealer). Stalling went away. In same year, had front struts replaced (with identical, proper parts, as always)

In summer 2005, weird issue arose. For some reason, I was experincing stalling at seemingly random times, i.e. when driving wot but also when coming to stop light. This is after bypass valve replace, and felt different. Also, much rarer than when bypass valve issue, which I could replicate almost every time if I wanted to.

Seemed to get worse as weather got hotter. Also noticed that seemed to be MAJOR tie in to whether air was on (auto) or else off (econ). When on (econ), don't think I had a single stalling issue ... maybe one or two at most. So, I drove around for the summer with the windows open.

... um, let's see. This fall, car went out on me. Brought it in to a trusted mechanic: The car had surged forward and in rpms and then just shut off HARD (really HARD) while driving. Couldn't get engine to turn over. Electric power was still fine. After he replaced "ignition coil" and ECU, finally concluded that it had to do with a belt being lose, causing timing to get screwed up!?! Something about precise elasticity and age? So, replaced the ?timing belt?. Car worked again. No stalling. Not sure if what was done will also fix earlier stalling issue (hopefully will). Obviously, since its only April 22 haven't tested it in hot weather with air on.

That's the history.

As I said, big concern = no boost. I'm not very confident working on the car yet, but I've been learning.

The thing is: In 03', when I first realized that max boost should be 1.8 bars (!), I brought the car into the local Audi dealer, whom my family really trusts. (My Dad is a customer there -- this was his car, he now has an 04' A8). I was embarassed: the technician said they inspected "the hoses" and found nothing wrong. WTF could I say? When I asked what was then causing the low boost (which at the time was about 1.3) just looked at me. Maybe he was referencing a 200 10v manual from Canada???

I've visually inspected the engine (which I know is no perfect way to check) and can't, as best as I can tell, see any rips/tears in classic hoses.

I'd really appreciate the input of this board and its members if you have the time. I'd like to know your thoughts, how to start, what might be wrong, etc. I love the car, despite its age, I'm interested in learning, etc. But I want it to be the turbocharged beast that it should be!

I can give more information about whatever, just ask. Thanks in advance.

Arthur

P.S. Despite what this post may sound like, the car (at least outside of the engine) is in near mint condition! Don't think I haven't been trying to take care of it! (white pearlescent paint is still 100%!)

Black-Wolf

check the basics including the turbo... make sure it isnt set up. check the intercooler and plumbing for leaks, tho a gradual decline over time says a slowing/seizing turbo... as the oil cokes up on the bearings it spins less and less. hopefully his isnt the issue as its more common on turbos that are not water cooled.

Kneale Brownson

If you want to know how things work and what can be a problem with the 200q20v engines, read Scott Mockry's 20-valve turbo information and learn how to read out the ECU's code report.<ul><li><a href="http://www.sjmautotechnik.com/trouble_shooting/20vboost.html">http://www.sjmautotechnik.com/trouble_shooting/20vboost.html</a</li></ul>

4Driver4

Replace it.

ArthurKing

4Driver4: Thank you. Direct advice helps because I think I might be in over my head ...
Could you give me a bit of 'how to'?

Black-Wolf (and everyone really): is there a good online resource that gives clear diagrams / schematics for the engine so that I could check the "intercooler" et alia?

Also, what do you mean by the turbo being set up? How could I check if oil is leaking onto it.

4Driver4

<ul><li><a href="http://members.aol.com/c1j1miller/main.html">Chris Miller's excellent 200 20v site</a></li></ul>

aerohr

if you don't... well... there is always the gt2871!

Seriously, though... open up the hood and pull back the throttle body and rev the engine right up and listen to hear if the turbo spools up a bit. 1.0 means you aren't getting any boost which could very well mean you have a toasted turbo.

Don't get frightened yet, though... the turbos usually are pretty robust, especially stock with low miles such as yours is...

Boost leaks are the number one most insidiously evil cause of bad boost - you need to make a pressure cap and hook it up to an air compressor... its an easy job to make one - simply a 3" PVC end cap with the threads filed off... tap a tire fitting into the middle of it and bang - you have a pressure cap. Put this on the turbo inlet hose (the big hose that feeds to the MAF and air box) and pump some 15 PSI pressure into it and listen for leaks... its normal to leak from the oil cap and dip stick (a little on both) but otherwise if you hold those down there should be no air leaks... if there are... repair them - thats likely your issue.

there are a host of sensors and what have you that can screw up too and cause a no boost issue... those are covered on SJM pretty well.

Also, have you pulled the codes? Really a good idea to do that before you start replacing things etc.

IM me at BelmontDecade if you want to talk further - I've not too busy this week and am always down for an audi conversation (especially with someone who has my twin car! Pearl 20v baby... oh yeah)

audiqv8

<ul><li><a href="http://www.intendedacceleration.com/technical.html">Intended Acceleration</a></li></ul>

ArthurKing

Thanks for feedback everyone. The websites are awesome, although it's going to take some time for me to sift through.

I'm out of town for the nxt. 2 weeks, so I don't have physical access to my car, but when I get back, I'm going to start the efforts!

I can almost guarentee I'll be posting here. (Hopefully, with more specific questions)

Thnx you! (If anyone has anymore specific ideas, I'm all ears ... I'm still confused about the 'turbo set up' comment ...)