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Old 04-29-2013, 06:26 PM   #1
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Default Slow acceleration (1.8t quattro tiptronic)

Hey there, I have read many posts on here and other forums about sluggish acceleration and I'm trying to get some direct answers and/or insight on my issues. Basically, the problem is when at a stop, my car moves SO SLOW. Snailing along until turbo begins to spool and I still accelerate slowly. I understand my car only has 150hp and it's definitely no S4, but I know when something is wrong. It's been a real damper on my mileage and self-esteem. My A4 is completely stock. No aftermarket diverter valve or anything, which i am aware I should replace ASAP.

Anyways, I'm thinking it's a boost leak. What are the most common areas to keep an eye out? I heard the diverter valve is common to fail. Before I do a boost leak test, I'm trying to do anything that could solve or make the problem apparent. My first step is cleaning the MAF. I currently do not have a CEL so I'm hoping if i clean it it'll give me a correct reading. After that I will proceed to get a boost gauge to test for a leak. If a leak is apparent via gauge, I will run the test. If not, should I run the test anyways? Say I have no leak, what should my next step be? Should I see if the throttle body (drive by wire) needs correcting? Is it possible my car is stuck on a lower fuel mapping therefore I am running rich?

the sluggish acceleration seems to get worse by the weather. The colder it is, the longer it takes to get up to speed. This issue made me believe it could've been the transmission. I've been considering getting it flushed and fluid replaced, but I've heard the fluid lasts a life time. Does anyone have correct information on that?

1. Clean MAF
2. Boost gauge test
2b. Boost leak test
3. Throttle body.

Is there anything else I should do before or after any of these steps?
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Old 04-29-2013, 07:19 PM   #2
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How many miles are one the car? I personally had a similar issue on a buddies car. And we checked everything. Found out it was a clogged catalytic converter. Already has a test pipe laying around and it fixed the problem.

Might also want to check fuel filter maybe even fuel pump going bad.
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Old 04-29-2013, 07:26 PM   #3
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137k. A friend and myself disconnected the cat one day to test this theory, it ran the same. I replaced the fuel filter myself last fall (Which was a pain in the ***).
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Old 04-29-2013, 07:57 PM   #4
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You're on the right track with the boost gauge. Just slap a vacuum tee into the FPR line off the intake manifold and run the tubing out the cowl and into your open window for diagnostic purposes.

One thing to think about: You can HEAR a boost leak in most cases. Also it'll set the CEL, I think.
My '98 Passat (AEB engine, FWIW) had the wastegate flap fall off. No CEL (believe it or not). The dealer could find nothing wrong - while it was in warranty (Hallmark VW in Madison TN, they SUCK, don't get me started). It drove like it was towing a boat. 16 sec 0-60. Ended up I had to take the turbo off and drill & tap the flap itself (which I found in the downpipe, glad I had the catalytic converter or I'd never have found it). Runs like a new car after that!

I detailed it all on PassatWorld or VWVortex. If your boost gauge shows 0 boost I'll find it for ya...

Also, if you could find someone to scan with VCDS it'd help.

-Tom
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Old 04-29-2013, 08:07 PM   #5
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My 0-60 is 19 seconds. No joke, it's pretty ridiculous. I made a VWVortex account today (Username: Braytonbuddy) I'm in Utah and I saw a post on VWV with a list of people in my area with Vag-com and I'm trying to get a hold of one of them. Is there a way to makesure my wastegate flap didn't fall off without having to take out the turbo? My mechanics knowledge on these cars are minimal, but expanding. Today I completely removed my airbox. If I can check the wastegate with the airbox removed, I'll have to make sure I didn't run into that problem.
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Old 04-29-2013, 08:41 PM   #6
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Click the image to open in full size.
^^NOT normal
The thing with the hole in it is the wastegate arm. The flap that closes off the exhaust to route the gasses through the turbo to spin the vanes is supposed to be attached to the hole!
At the bottom of that pic you see the cute little vanes of the K03 turbo.
At the top you see the wastegate rod (which I'll abbreviate WR) with its dampening weight and long threads. It normally goes through the blurry thing with the hole in it which its nut is resting against in the foreground.

To see the normal view, see this: passatworld

You gotta have the exhaust off to see the flap missing, see this thread...

You can tell if it's detached, the WR will be rattle-y but if it's just loose, it's hard to discern unless you know what the WR is supposed to feel like. Plus it's hard to get to the WR cause it's behind the turbo.
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Old 04-29-2013, 08:44 PM   #7
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Quote:
Originally Posted by Brayton View Post
...Is there a way to makesure my wastegate flap didn't fall off without having to take out the turbo?...
BOOST GAUGE

It won't tell you if yer wastegate flap's on for sure, but if it's OFF, your new boost gauge will read ZERO on the boost side.

You can take off the three bolts holding the exhaust to the turbo and get just enough clearance to feel in there. At least with the FWD cars. Sorry I know this is not the answer you'd hoped for.
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Old 04-29-2013, 08:59 PM   #8
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I'll have to remove my airbox tomorrow and see if I can see anything wrong or that looks bad. I might get a boost gauge tomorrow and some MAF cleaner. I also might run a boost leak test. I'll keep you guys posted on my findings.
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Old 04-30-2013, 03:52 AM   #9
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Pull codes in both ECU and TCU.
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Old 04-30-2013, 11:04 AM   #10
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Update:
I replaced my air filter and cleaned my MAF. Installed a boost gauge. When full throttle the gauge reads 4psi. I'm hoping to run the boost leak test later today.
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Old 04-30-2013, 11:04 AM
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18, 18t, 2003, a4, acceleration, audi, b6, boost, poor, quattro, slow, tiptronic, turbo, upgrade, vacuum


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