DV Flutter, what should i look for? Symptoms?

[getslideways]

So my car sounds like this video when i let off the throttle:
http://www.youtube.com/watch?v=H0EUJ080qno

And it has recently come to my attention that it should sound more like this:
http://www.youtube.com/watch?v=uKrZDGr03y4
or
http://www.youtube.com/watch?v=69SJC-8kttc

am i correct in thinking something is certainly wrong here? Just wondering what things i should look? Also will this most likely affect my performance at all with the DV fluttering? Like laggy turbo response, lack luster performance etc.? Or are there some symptoms that would be associated with this? I have never driven another A4 so i didn't even know my car was doing anything wrong until i was reading some comments about that first video on a thread on this site.

So far from what i have searched i need to check the vacuum lines to the DV for leaks. What else can I do to narrow down the source of the problem? I did a boost leak test a while ago and turned up a trashed check valve, and a ripped L-hose both have been replaced.

Thanks!

My car: 2000 a4 1.8t, Carbonio Intake, boost gauge, otherwise bone stock.

[AE Performance]

Well, a big sign of a DV failing is it'll honk, sorta like a duck sound. Its very noticeable... however, it doesnt have to do this. If the car feels sluggish and you notice it being much slower than you remember it being with boost seeming to flutter quite a bit when youre on the gas, chances are the diaphragm could have torn in your stock valve. We're still running a special on forge DV's if youre interested.

[getslideways]

Well, a big sign of a DV failing is it'll honk, sorta like a duck sound. Its very noticeable... however, it doesnt have to do this. If the car feels sluggish and you notice it being much slower than you remember it being with boost seeming to flutter quite a bit when youre on the gas, chances are the diaphragm could have torn in your stock valve. We're still running a special on forge DV's if youre interested.

Thank you for the insight. If i take out the DV will i be able to visually see a torn diaphragm or test it? Or is the unit completely sealed? I have never driven another 1.8t quattro a4 to compare my car's performance to, but it does feel a little lack luster and sluggish especially from a stop. Although the boost gauge doesnt seem to jump around. About 6 psi in 1st-2nd gear then the higher gears about 8 psi. Does this sound about right for a 2000? I thought i had read that was right, but i could be wrong. Looks like i may be taking you up on that sale after all!

[2K1Ultrasport]

fluttering dv def robs boost/power.
i serviced mine (forge) and got right back up to peak boost.
your psi seems a bit low, i thought stock 1.8s peaked somewhere above 10psi.
(could be wrong here)
which dv do you have?
the stock audi ones wont hold too long if you're chipped or above.
you can always try the pen test.
push in the valve with a pen and then plug the other side with your finger.
the valve should stay pushed in until you release your finger.
if you have an adjustable dv, make sure you're using the right colored spring for your application.
and def replace the stock dv vac line with a nice silicone piece.

[getslideways]

Thanks, the DV is just the stock unit, the car is all stock minus the intake, and I am not sure if i will end up chipping it or not (but most likely the speed bug will bite!)

i thought the psi numbers were normal for the ATW motors to have that range of boost, but today after reading my gauge again i think my numbers might be more like 5psi low gears and 7psi in high gears which would be low even for what i thought it should be (could just be the way i am looking at it though, or maybe i am reading the gauge wrong during the quick glances). But the boost pressure doesn't seem to fluctuate when on the throttle. Maybe there is something going on here.

Also: is that normal for it to read different PSI in 1st and 2nd gear compared to 4th and 5th? (i cant remember what it is in 3rd) i thought i had read that was normal, but maybe not.

thanks so much for all of the help so far! I will have to try the pen test!

Also any confirmation of ATW stock boost pressures?

[2K1Ultrasport]

stock AW psi is 8.7 from what I found.
Don't know if it's supposed to peak at higher numbers or not.

[AE Performance]

Thank you for the insight. If i take out the DV will i be able to visually see a torn diaphragm or test it? Or is the unit completely sealed? I have never driven another 1.8t quattro a4 to compare my car's performance to, but it does feel a little lack luster and sluggish especially from a stop. Although the boost gauge doesnt seem to jump around. About 6 psi in 1st-2nd gear then the higher gears about 8 psi. Does this sound about right for a 2000? I thought i had read that was right, but i could be wrong. Looks like i may be taking you up on that sale after all!

They seem about right... stock boost is around 8psi or so on a b5. Chances are that if the valve is stock, its probably wearing out by now so it may not hurt to swap it. But like I said, its a bit more difficult to tell on a stock car. On a chipped car its really obvious when a DV is starting to fail from the sound and really choppy boost.

[getslideways]

i found this today when poking around in my car:

http://www.audizine.com/forum/showthread.php?t=225912

could this be related to the reason the valve may be acting up?

[qtek16]

So my car sounds like this video when i let off the throttle:
http://www.youtube.com/watch?v=H0EUJ080qno

And it has recently come to my attention that it should sound more like this:
http://www.youtube.com/watch?v=uKrZDGr03y4
or
http://www.youtube.com/watch?v=69SJC-8kttc

am i correct in thinking something is certainly wrong here? Just wondering what things i should look? Also will this most likely affect my performance at all with the DV fluttering? Like laggy turbo response, lack luster performance etc.? Or are there some symptoms that would be associated with this? I have never driven another A4 so i didn't even know my car was doing anything wrong until i was reading some comments about that first video on a thread on this site.

So far from what i have searched i need to check the vacuum lines to the DV for leaks. What else can I do to narrow down the source of the problem? I did a boost leak test a while ago and turned up a trashed check valve, and a ripped L-hose both have been replaced.

Thanks!

My car: 2000 a4 1.8t, Carbonio Intake, boost gauge, otherwise bone stock.

get a new one

[qtek16]

but on a serious note--One i think that you tube video was a golf or jetta and two, the car was stationary--that will change the sound

Good possibility you have breather hose/hoses going bad or are bad--you will get that smacking sound when that happens--When they completely fail you will know it.

[boostedup]

i just had this problem, my 710n failed on me after about 1 year and a half of being chipped (i installed the valve the day i got chipped). like someone said above, at partial or full boost my car sounded like there was an effin duck under the hood, and the boost fluttered all over the place......

[tamadrumr88]

my dv would flutter when the vacuum line from the manifold was torn. boost dropped from ~20 to 7... replaced the line and all is good

[pipe7284]

^^^agree, it is definately your hose that goes on top of the DV to your intake manifold that is torn. check for that first before buying a new one.

[getslideways]

^^^agree, it is definately your hose that goes on top of the DV to your intake manifold that is torn. check for that first before buying a new one.

I checked the hose, and it seemed fine, i replaced it since i was there, and it made no difference. I pulled out the DV and tried pushing the piston up with a socket, then holding my thumb over the vacuum port, and the piston would slowly close then there would be little to no vacuum on my thumb. So looks like i am most likely looking at a bad DV with a torn diaphragm. Anyone have quick guess as to the cost of an OEM one from the dealer?

thanks for everyones help in tracking this down

[cmagalis]

Before you get a new valve really look the car over intensively. To me it sounds like there is a boost leak somewhere. Honestly I would change out all the factory rubber crap (boost hoses) because its prone to fail anyway. If this doesn't fix the problem then replace the DV. What your going to want is a samco (www.sporthoses.com for $250) boost hose set. Even if there isn't a boost leak they look good, will give you a little tighter throttle response, and won't fail in the future. Also go to ecstuning.com for the dv valve ($44) in the engine parts category. So your looking at about $300 to make your car run right and prevent future hose failures.

[2K1Ultrasport]

def do not buy the dv at a dealership.
you could probably get a forge or baileys for a little over what the dealer would charge you for a stock dv.
as for the vac lines, seems like it wasnt the issue since your dv was failing the test anyhow.
but def a good idea to replace em while you're at it.
you already got dv line, the other you should def replace is the one that runs to your fpr.
obviously itd be good to replace all of em, but some are a bitch to get to.

[getslideways]

well looks like i am in the market for a new DV. i have had to already replaced most of the major problem hoses (check valves, "L" hose, and a few others), but that doesn't mean there isnt a vac leak still in the system somewhere, but the boost gauge reads normal (what i think is normal) at idle, about 22 in/hg.

[AE Performance]

well looks like i am in the market for a new DV. i have had to already replaced most of the major problem hoses (check valves, "L" hose, and a few others), but that doesn't mean there isnt a vac leak still in the system somewhere, but the boost gauge reads normal (what i think is normal) at idle, about 22 in/hg.

Well, if you'd like to go in the direction of a Forge DV, let me know and I can take care of you. :)

[Mott6904]

so did you replace your dv? did it make any difference in power?