[jddaigle]

Question for all the turbo-types:
I've had my new-to-me 2001 Jetta Wolfsburg (31,000mi)--my first 1.8t--for 2 months now and am wondering about a high-pitched, rapid flutter noise that I hear when I step ON the throttle while moving. It doesn't occur if I rev the engine while stopped. It starts as soon as I step on the gas, and stops as soon as I let off. Its pitch increases with road, not engine, speed, until it gets too high for me to hear around 50mph. The car's performance is normal (compared to other 1.8ts I test drove) and when the dealer checked for codes when they replaced the coils nothing came up. So, is this a normal 1.8t sound, or what? Thanks everyone--
edit: to, too, two...


Modified by jddaigle at 12:24 PM 7-16-2003

 

[JettaRide]

Re: rapid flutter while on throttle (jddaigle)

Does sounds are known to be caused by a bad bv, check that!

 

[jddaigle]

Re: rapid flutter while on throttle (JettaRide)

As I understand it a bad DV makes a noise when coming OFF throttle, where as my sound only appears when I am ON throttle. That an the fact that the dealer found no codes just a week ago make me think the DV isn't at fault. Am I mistaken here?

 

[turbovw18]

Re: rapid flutter while on throttle (jddaigle)

it's not the turbo is it ?

 

[jddaigle]

Re: rapid flutter while on throttle (turbovw18)

Quote »

it's not the turbo is it?

No, I know that sound well enough! The turbo sounds good & healthy and pulls just fine. My Dealer has the TT DV in stock for $35, would it be worth it to grab it & see what happens?


Modified by jddaigle at 10:20 AM 7-16-2003

 

[Androoos]

Re: rapid flutter while on throttle (jddaigle)

might be...from what i've been able to tell, it might be the DV opening too soon or something like that. if that doesn't solve the problem, at least you'll have a spare DV in case it does fail at a later date http://****************.com/smile/emthup.gif good luck, keep us posted

 

[US MARINE BORA 18T]

I had the same problem also with out the a cel. It was the dv, I had it replaced under warranty. I wonder why mine went bad my car is stock and I thought the 03's use the oem tt dv

 

[JettaRide]

Re: (US MARINE BORA 18T)

A dv can fail in many ways, not only the known flutter when you realese gas, for 35 bucks I would do the swap and see what happens.

 

[jddaigle]

Re: (JettaRide)

I picked up the TT DV from the dealer & will install it when I get home tonight. Thanks for the ideas, I'll keep you posted.

 

[wsaenotsock]

Re: rapid flutter while on throttle (jddaigle)

Didn't KrautFed post something like this a long time ago about another local guy's car doing this?

Only time I can remember flutter when on throttle.

 

[jddaigle]

Update

Well, it wasn't the DV. Turns out I already had a 710N DV in there; now I've got a spare. No change after installing the new DV. I'm trying to think what else it could be; the sound appears around 30mph and gets too high to hear at 60mph or so. Doesn't happen when I rev the engine. Could it be something to do with the throttle body?

 

[lickmyhead]

Re: Update (jddaigle)

I am having the same problem, i think. I have a APR DP, and i think the bolts that connect the DP to the turbo are loosening up and causing the sound. (I only get the sound when under throttle in gear, not when im stopped and revving.) I am having it checked out while the drivers side of my car is getting fixed. (Long story).

 

[JettaRed]

Re: rapid flutter while on throttle (jddaigle)

Keep in mind that you generate boost when under load, not when off-throttle or while revving in neutral (the turbo will spin, but with no load the DV is open and boost gets recirculated). The sound you describe sounds like air escaping through a small opening. You may have a boost leak somewhere. I don't know where to begin to check, I'm just stating a potential problem.
Since you bought the car used, the previous owner may have done something to cause a boost leak.

 

[jddaigle]

Re: rapid flutter while on throttle (JettaRed)

Quote, originally posted by JettaRed »

The sound you describe sounds like air escaping through a small opening. You may have a boost leak somewhere.

I was wondering about that. The PO drove it conservatively, going by the condition of the other components (=immaculate). Any suggestions on common locations of boost leak?

 

[US MARINE BORA 18T]

Re: rapid flutter while on throttle (jddaigle)

if not the dv, than it might be a exhaust manifold leak try to retorque it..see what happens

 

[jddaigle]

Re: rapid flutter while on throttle (US MARINE BORA 18T)

Quote, originally posted by US MARINE BORA 18T »

if not the dv, than it might be a exhaust manifold leak try to retorque it..see what happens

Thanks--happen to know what the torque specs for the manifold are?

 

[JettaRide]

Re: rapid flutter while on throttle (jddaigle)

What about your idle??? Is it jumpy???

 

[jddaigle]

Re: rapid flutter while on throttle (JettaRide)

Quote, originally posted by JettaRide »

What about your idle??? Is it jumpy???

Nope, smooth as silk. That's the thing--the car is driving beautifully, and I'm wondering if this is just a normal noise from the intake and I'm being paranoid with my new baby. I suppose I could just have my mechanic check it out at the next oil change, but I'd rather not pay for dianostic time. <sigh>Maybe I should just turn up the radio and enjoy driving the car?