Chasing down a Vibration on Acceleration

BearForceOne

Active member
Joined
Jul 17, 2017
Location
MI, 48348
TDI
2001 Jetta, Tornado Red
Relevant info:
2001 02J ALH Jetta sedan
349k miles
New VR6 clutch/SMF conversion

Since I bought my Jetta in late August with 343k miles, any time I've started from a stop the whole car shakes pretty significantly, enough to make me believe it's not normal and acceptable NVH from the factory. No matter how much fuel I give it, how quickly or slowly I let off the clutch, there's always a moment of intense vibrations. There is no issue shifting gears when in motion, just when letting off the clutch while in first from a stop or very low speed.
Initially I believed it to be a bad dual-mass flywheel, which I found was very loose and needed replacement, but was not the cause of the vibrations. Next was a replacement driver's side engine/trans mount, and dogbone mount as both had a lot of miles on them and were notably loose. These improved the feel of the car a little, but the vibration still continues.
I'm running out of guesses as to what could be causing this, and it's really starting to get on my nerves. Perhaps my Google-fu isn't as great as I'd like to think it is, but I've been unable to find any related threads on the forum or posts online with similar symptoms.
Am I grasping at straws that it might be a CV shaft or transmission issue? Or maybe the fuel filter is plugged and the engine is being starved of fuel on launch? There is a notable amount of bubbles in the feed line between the filter and injection pump.

Any help is greatly appreciated, thank you!
 

STDOUBT

Veteran Member
Joined
Jul 30, 2007
Location
Portland, effing Oregon
TDI
dos jettas
A notable amount of bubbles? Like tiny, foamy bubbles? Or rather a couple of bead-sized bubbles that kinda sit there?
Foamy-ish would probably indicate a leak of air into the system, probably coming in at the "thermo-T" sitting in the top of the fuel filer.

Who put the SMF in? Have you ruled out the drive shafts/knuckles/drive flanges?

EDIT: and the best way I have found to search this site is use bing/google to search with "tdiclub" in with the search terms
 
Last edited:

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
I'd start by checking your IQ, sounds a lot like slow down shudder, but way worse.
 

jayb79

Top Post Dawg
Joined
May 20, 2000
Location
Exeter,NH
I just went through a vibration problem that ended up being a loose drive axle nut. Easy to check and eliminate, put a 12 point 30mm socket on it and see if its tight.
 

WildChild80

Veteran Member
Joined
May 30, 2016
Location
Nashville, AR
TDI
2001 Jetta TDI 2000 Jetta TDI 2000 New Beetle TDI ALL 5 speeds
My stock tdi does this, I cured it by adding a dogbone with red poly inserts, after almost loosing fillings or living in an earthquake(it literally felt like a pavement pounder was parked on the roof) I went back and put something soft back in there. I can pedal through it, no idea what the clutch is in it, I've only done suspension, seals and everything associated with the TB. I have a South bend stage 2 daily for it but acquired another project that may get the clutch.

It feels like the clutch has sticky glue on it, initially I had feared brake fluid leaking on to it but I'm not loosing fluid so I just live with it for the time

Sent from my Pixel XL using Tapatalk
 

03TDICommuter

Veteran Member
Joined
Dec 8, 2016
Location
So. Cal
TDI
01' NB, 5spd
When in gear but accelerating up a hill does it do it? Mine had a diagonal front to back shimmy and it was the passenger side inner CV joint.
 

Powder Hound

Top Post Dawg
Joined
Oct 25, 1999
Location
Under a Bridge, Crestview, FL, USA
TDI
'00 Golf 4dr White 5sp, '02 Jettachero 5sp, Wife's '03 NB Platinum Gray auto(!)
I concur. Steering wheel shimmy when pushing on the go-pedal is the inner CV joints. You can swap them side to side and get a new life on them if you want to stretch your bucks. More than likely you'll need to do something about both of them. Note: the steering wheel shimmy isn't really the same as a vibration, and the shimmy will show up anytime you hit the go pedal no matter what gear you are in. If your vibration doesn't fit this, then it is something else.

Do you have OEM half shafts?

Cheers,

PH
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
CVs sounds right.
There is also some general stuff on youtube, search vibration under acceleration.
If you don't already, try using google advanced searches, specify a site and play with the keywords. Or DuckDuckGo (they don't track you)
 

BearForceOne

Active member
Joined
Jul 17, 2017
Location
MI, 48348
TDI
2001 Jetta, Tornado Red
Thanks everyone, I'm gonna give the CV shafts a few good shakes while in the air and see if that leads anywhere.
There's no shimmy in the steering wheel, it's the entire car that vibrates hard. It does it up hills, on flat surfaces, and in reverse as well.
 

BearForceOne

Active member
Joined
Jul 17, 2017
Location
MI, 48348
TDI
2001 Jetta, Tornado Red
Bear i don't see where you said you ruled out the upper engine mounts.
[...]Next was a replacement driver's side engine/trans mount, and dogbone mount as both had a lot of miles on them and were notably loose. These improved the feel of the car a little, but the vibration still continues.
Two out of three mounts were replaced, the passenger side mount felt good when the engine was out to do the clutch. The rear bracket ear was broken off and was already been repaired with one of those kits
 

03TDICommuter

Veteran Member
Joined
Dec 8, 2016
Location
So. Cal
TDI
01' NB, 5spd
Jack up the car on one side so the front wheel is off the ground then rock it forward and back to see how much rotation play there is on the inner CV. Before I replaced mine I think it was about 1/2" of rotational play at the circumference of the tire. About 1/4" after I replaced the inner joint. Do it for both sides but my passenger side was worse.
 
Top