Significant vibration

oldpoopie

Vendor
Joined
May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
A customers car, 2001 alh golf, has a significant vibration at idle. As rpms go up, it is less noticable. Customer purchased the car with 40k miles. It exhibited his vibration at time of purchase. Flash forward 200k miles, and it still vibrates, perhaps a touch worse. The car has an old upsolute tune. Timing is spot on, IQ is at 4.5, injector balance is normal. Compression is 420, 410, 410, 420. Clutch and flywheel have been replaced. No codes. Engine does not burn oil, and gets 45mpg regularly.

Im at a loss. Any ideas?
 

mk3

Veteran Member
Joined
Sep 13, 2005
Location
Wisconsin, USA
TDI
03 Jetta GLS 5-speed
Motor mount condition and alignment?

What is the exhaust system like? stock mounting points and stock exhaust? or modified?
 

oldpoopie

Vendor
Joined
May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
I did the last timing belt 70k ago. The vibrationw as present then, as stated, and the motor nouts were fine
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
You might try a lower IQ value. Not sure if that would sync with the tune though.
 

oldpoopie

Vendor
Joined
May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
The car behaved the same when he bought it years ago..... before the upsolute tune so I doubt its that. Turbo is original, and is fine.
 

Mavrick

Veteran Member
Joined
Feb 16, 2012
Location
Ontario
TDI
2003 VW Jetta TDI
I had a similar scenario.. someone had replace the rubber in the dog bone mount with something like urethane. Replaced all 3 mounts. Nice and smooth.
 

oldpoopie

Vendor
Joined
May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
this isnt hard-mount vibration... This *feels* like out of balance or misfire vibration, but there isnt any actual misfire. Engine starts and runs *normal*

I'm very familiar with hard mounts and this is nothing like that sort of vibration.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
A borderline #3 injector? Check ohms?

And along those lines maybe there's been a marginal wiring connection to that injector (or to the IP)?
 

oldpoopie

Vendor
Joined
May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
I've thought about that but the injector balance is almost perfect. Also how would a #3 injector be borderline for 200,000 miles. vibration has remained consistent throughout the 200k.
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
I've thought about that but the injector balance is almost perfect. Also how would a #3 injector be borderline for 200,000 miles. vibration has remained consistent throughout the 200k.
It came off the manufacturing floor at one of the statistical ends of the curve (and given that most production at these levels of volume you can actually lose stuff out the door that's outside of the acceptable range).

The #3 provides a basic signal that then instructs all fueling, doesn't it?

Needle is slightly sticky? Perhaps DBW could comment on such things?

Just seems that the problem is hiding in something that's in plain sight (something that one just never expects). For someone like you to struggle with something seems to suggest that it's something that just shouldn't be that is.

Might be more that the physical dimensions are outside of what the signals are expected to see, a scenario totally undefined, not even falling into the "implausible signal" category (and, based on the fact that it's not causing really bad behaviors, it's a subtle difference, one that would cause this vibration at idle [a mechanical balance issue would only seem to increase with rpms, so fueling feels more appropriate).

Wouldn't take much to test the hypothesis of it being a mechanical issue with the number 3 injector.

I'm trying here. I wanted to be a professional muse, but it just never goes down well on a job application form. So, I just continue with it as a hobby.:D
 

Drivbiwire

Zehntes Jahr der Veteran
Joined
Oct 13, 1998
Location
Boise, Idaho
TDI
2013 Passat TDI, Newmar Ventana 8.3L ISC 3945, 2016 E250 BT, 2000 Jetta TDI
Bent rods #2 and #3.



The rods are more than likely very slightly bent causing your eratic vibration.

Causes:
- History of blown turbo. hydrolocked engine bending the #2 and #3 rods. The reason is that oil drains first into the inner cylinders due to the shape of the manifold.
- History of "Foam Piper Cross" air filter (water ingestion)

I know you can take a valid compression reading with the best of them, and the evidence points to rod damage.

The rods if bent won't necessarily fail, but they can exist with mild bending for a long time.

I'd say measure using a glow plug insert actual cylinder extension as you rotate to TDC.

Note the Degrees BTDC that the piston stops moving, and ATDC that it begins moving again. You can then bracket the approximate bending moment of the rods.

As the engines injectors age, the variation in compression will become more evident as the flow balance moves away from optimum. The crank acceleration may be close enough that the "Balance values" appear normal because of the +/- relationship of the sister cylinders being slowed due to the damaged cylinder crank acceleration differences... In other words its going to be really hard to see using Group 13 data.

Start with Rods, and measure piston extension.

My best guess with what little I know of the motor, but the symptoms fit.

Eliminate those and I'd start looking at a bad harmonic balancer or one that is out of balance or a brittle rubber bonding between the two metal sections.
 
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oldpoopie

Vendor
Joined
May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
Thanks Pete. I'm leaning away from bent rods if only because the engine doesnt burn any oil and hasnt for 200k. When I very slightly bent the rods with my upsolute tune, my engine continued to run smoothly, but burned oil.

Also, the 10psi variance between cylinders is within the margin of error of the testing equpment (and operator LOL). Not to mention the same gauge was used to test a known good fresh built motor that tested at about 410 across all 4 cyl.

Since he has driven it for 200k like this, and the car runs and drives fine, we will not be pulling the head to measure piston protrusion. Indicating thru the glow hole is an interesting idea.

Turbo is factory original.
Airbox is factory original and never messed with.

I like the harmonic balancer idea.... Ive got a spare.
 

Drivbiwire

Zehntes Jahr der Veteran
Joined
Oct 13, 1998
Location
Boise, Idaho
TDI
2013 Passat TDI, Newmar Ventana 8.3L ISC 3945, 2016 E250 BT, 2000 Jetta TDI
For Piston / rod measurement, remove. the glow plugs and use an extension on a dial indicator (do you Still have one for setting IdI pumps...I do and it works great for something like this).

You can use the TDC dent on the harmonic balancer and scribe 30mm left and right of it to bracket the crank rotation window.

Otherwise harmonic balancer is next.
 

dtrvler

Veteran Member
Joined
Jul 21, 2017
Location
Las Vegas
TDI
2006 Jetta TDI 5 spd
I know this is an old thread, but i really wish people would post the result/ solution, causes etc of their issues for the benefit of others.
 

oldpoopie

Vendor
Joined
May 14, 2001
Location
Portland Oregon
TDI
2001 golf gl, 2006 jetta, 1981 ALH swapped rabbit pickup, 1998 beetle
Never did figure it out. Since car ran fine and customer decided to not spend any more time or money chasing the issue
 
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