Golf 1Z: Excessive Engine Vibration?

Hello!

I've been driving a 3-series Golf TDI with 90 horsepower for a year.
'I had the engine mounts replaced 9 months ago because they were too soft, and the engine was shaking when starting.'
Since then, a persistent and strong vibration has been spreading throughout the entire car, originating from the engine. It's especially noticeable when the car is idling. The vibrations have even caused my rear muffler to detach!
The error memory is empty, the injection timing is still within the acceptable range, the engine has full power, and the engine sound is actually okay; I've already compared it to several other TDI engines.
Does anyone have a suggestion as to what might be causing this?
In addition, the engine has a quirk: sometimes (and it's hard to provoke!), it experiences something like brief misfires at about 3300 RPM when running at about three-quarters load (yes, it's a diesel, but that's the best way to describe it). However, it then continues to run normally.

Thank you in advance!

Andreas.

Hi Andreas,

haggis.dhi wrote:

...Furthermore, the engine has a quirk where, at about three-quarters load and around 3300 rpm, it sometimes (you can't really provoke it!) experiences something like brief misfires (yes, it's a DIESEL, but that's the best way to describe it), after which it continues normally...

Try entering "faulty needle valve distributor" or "defective NHG" into the search function; you'll likely be overwhelmed with similar problems.

/viewtopic.php?t=1028&highlight=needle_knock_generator+defect

/viewtopic.php?t=1498&highlight=needle_hub_generator+defect

Another potential cause of dropouts can be the power supply relay (labeled "109" - hence, it's often referred to as "Relay 109"). Use the search function to find information about it as well.

Okay, thank you BERTIL!

It seems the NHG has a problem; I tried the knock detection method, and the engine occasionally made strange noises.

But I doubt that's the reason for this awful vibration, because it's strongest at idle, and the NHG (noise, heat, and vibration) is mainly responsible for the load range. Also, the idle speed is fine. I've been to many workshops, but no one could say anything; I was only advised to replace the tensioner for the ribbed belt first, because it's already worn out (the tensioner is already new). Furthermore, one mechanic suggested it might be due to the bearing where the crankshaft exits the engine to drive the ribbed belt.

Regards,

Andreas.

Hello Andreas,

Is your timing belt gear securely attached to the crankshaft, and is the retaining screw also tight?
Please search for "1Z timing belt" and select "Search for all words".

Best regards, Rainer.

Hello Andreas!

"I once had a similar "vibration" on my Passat, which was particularly annoying when idling with the car stationary. In my case, the problem was with a flexible pipe section, about 10 cm long and covered with steel wire, located in the exhaust system between the turbocharger and the catalytic converter."

Best regards,

JRoth