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?
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.
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.
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.
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.
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.
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.
Update: I ran a boost leak test. Did the tennis ball and compressor test. Didn't find any leaks. My friend had a scan tool and found out my throttle body is running at 75%. Would this create the substantial decrease in performance? How can I fix this? Vag-Com?
...My friend had a scan tool and found out my throttle body is running at 75%...
I'm not sure what that means, but yes; if there IS something wrong with your TB, VCDS would probably show it. You're on the right track in trying to connect with a local VCDS owner.
4 PSI is odd, I expected zero (normal is about 8 PSI I think). IIRC there are some vacuum lines which carry less than full vac/boost; you didn't tap one of those, did you? (no offense, just trying to cover all the variables).
My car was overfilled by a quart by the geniuses at HALLMARK VW, MADISON TENNESSEE (don't get me started, again ). My puck valve was full of oil, and there was a lot of oil in the intercooler and in the crossover tube (big metal pipe below the radiator) and into the TB, too. It (TB) still needs cleaning at each oil change, then it runs better. I take off the crossover pipe (lowest point so that's where most of the oil collects) and drain a tablespoon or so. When you had the intake apart did you see any oil? maybe that's messing with the TB, causing the reading your friend's scan tool picked up.
You might consider searching Passatworld.com, too. there are a high percentage of 1.8T owners there.
I spliced that line that goes from the DV to the intake (I believe that's what the line is) at this point I'm sure it's either my TB or its just an old turbo. Thing is 14 years old so I wouldn't be surprised if its just dying. Just an excuse to slap on a K04 and get my ecu flashed. Im goin to contact a dealer today to get a price on a scan if I can't get a hold of anyone. Thanks for the support guys!
Try pulling a vacuum on the DV valves little vacuum line, if it doesnt hold, the diaphragm is ripped. If its springs broken, it will just open right up and bleed all your boost back to the front of the turbo. Also if the little solenoid that controls the wastegate isnt operating correctly, the vacuum lines have collapsed or been blocked or are rotten, or its just bad, you wont be getting much boost.
BTW turbos dont just get tired, they work till they smoke like hell or something breaks. my 200 Avant has 270k on the original engine and turbo and a 1.8bar spring and chip from 70k miles according to the giant folder 6 inches thick of paperwork for the car. And it still pulls hard for a big old wagon haha
2000 Audi A8L 4.2
1999 Audi A6 Avant 2.8
1998 Audi A4 quattro 1.8T
Last edited by Prospeeder; 05-01-2013 at 12:09 PM.
Finished the VCDS scan. I think it said my boost pressure control valve was bad, my throttle body position sensor was bad, and my transmission throttle body sensor (or something like that) everything else was just minor stuff. Like my fuel sensor(tells me i'm empty at half tank) and my front passenger anti-theft sensor.
Would the PCV and TB position sensor cause these problems I'm having?