Passat 1Z Engine Problems: Troubleshooting Guide

Hello,
'My engine (1Z in a Passat Variant, manufactured in 1994) has approximately 170,000 km on it. Lately, it seems to be running unevenly when idling, i.e., when coasting on the country road, but it sounds relatively normal when accelerating. Some people might say it's the tires, but the noise disappears when I press the clutch. I replaced the injector for the 3rd cylinder about 50,000 to 60,000 km ago; it's a common problem with the 1Z engine.'
Could it be the fuel injectors? Or what about the engine mounts?
Can I pinpoint the problem more precisely?

Sure, here's the translation:

'Thank you.'
Best regards, Thomas.

You can often "hear" if an injector nozzle is faulty.

- Warm it up.
- Let it roll down the mountain so that it reaches, for example, 2000 RPM when you take your foot off the gas.
- Now it's not injecting anything, so the injectors aren't doing anything, and you can hear the pure sound of the engine running and the compression.

- If you gently adjust the accelerator pedal now, you can already distinguish between the sounds of the turbocharger and other engine noises.

My 1Z makes uneven noises even with the nozzles installed; without them, the sound is smooth.

So, eventually the nozzles will need to be replaced (80 EUR from BOSCH, and they can be refurbished).


m;

Hello Dieselmartin,
Thank you for the quick response. The question is, of course: when should we react, or rather, when is it necessary to replace the nozzles?
And what about the engine mounts? When I move the engine back and forth, there's quite a bit of play in them!

Best regards, TD.

The three items together cost, as far as I'm aware, 180 EUR.

It is sometimes possible to act "on suspicion."

You can only tell how wobbly the engine is by actually being next to it.

m;

Okay, so I tried it out today. When I'm "playing with the gas," I can't really hear anything. The car just rolls along, making a steady noise. You can definitely hear that it's a diesel engine, a really nice sound. But as soon as I give it a little more gas, there's just a slight rattling, and the turbo makes a whooshing sound. That's all I hear.

I listened again. You can actually hear the differences, but it seems like you have to drive it around 1800 RPM for the turbo to engage properly.
I would describe the engine's running sound when fuel injection is occurring as more "rough" rather than a smooth idle. But it's not uneven; it's just rougher, and I don't hear the characteristic "knocking" sound as much either.