VP37 Leak: Causes and Troubleshooting

hello

"I'm experiencing intermittent leaks in my TDI engine. Sometimes they're minor, but then they become quite severe, filling everything up and making it difficult to see anything. What's strange is that it seems to be leaking up to the alternator/AC compressor area, which suggests it's coming from the high-pressure side."

Everything is fine above, the manifold/pipes/return line - all are clean.

Sporadically occurring errors are my favorites.

That's why I've tried quite a few things - the first thing I did was remove my "Kärcher" control unit. I also checked all the wiring and made sure everything was properly connected.

Well, at least it's been quiet for a few days now.

Could it be that chip tuning increases the pressure *inside* the fuel pump? I mean, I doubt it, right?

"Thank you."
Sure, here is the translation of the text from German to English:

"Hello"

Quote:

Could it be that chip tuning increases the pressure INSIDE the fuel pump? I mean, I don't think so, right?

Are you talking about the tuning box? No.

With chip tuning, there might be a slightly higher pressure at the fuel injector control valve if the injection timing is significantly advanced, but whether this actually causes leaks is just a theory.

Alternative theory: Your fuel injector return lines might be slightly leaky, and the longer injection times could cause the large amount of fuel leaking from the (worn?) injectors to drain too slowly. There might be a blockage in the return line. Are you absolutely sure it's coming from the pump?

Biodiesel drivers?

hello & thank you.

The injectors have been replaced. I also replaced the oil return lines in the process, but as I said, everything is verschandeln up top. The diesel engine is located in the lower area, along with the air conditioning compressor and all the associated lines and cables. At least it's enjoyable to work on like this.

"Biodiesel was used in the car until 2002, which is when I bought it. At that time, I initially sealed the fuel mixture adjustment mechanism. However, that was about 160,000 kilometers ago."
I usually use premium gasoline, and occasionally add oil.

@vwschrauber: The fuel injector adjuster is attached with two screws. And that's exactly where it could potentially leak - theoretically. It's located approximately in that position.
Can I disassemble it and reseal it?

Sure, here is the translation of the text from German to English:

"Hello"

It's possible that you have a hairline crack in a hose that only leaks at certain engine speeds.
If diesel fuel is leaking, it should always be leaking, because with almost no particles inside, any crack or similar damage cannot close itself.

How often does this happen?

Sure, here is the translation of the text from German to English:

'Lg' is a German abbreviation that stands for 'Liebe Grüße,' which means 'Best regards' or 'Warm greetings' in English.

Well, now there's a period of calm again. But it's a little bit clammy – as long as it stays like this, I'm relieved.

There's a leak somewhere around the "lid" of the spray adjuster.

Sure, here is the translation of the text from German to English:

"Hello"

The solenoid valve for the injection molding machine has an O-ring, which, like the O-ring on the high-pressure side, seals against the outside. This is another potential source of leakage.

If you replace it (which may be possible without removing the pump), it's best to also replace the second, smaller O-ring located behind it on the injector control solenoid valve, as this could lead to an "injector control differential" error, even if the pump appears to be leak-free from the outside.

EDIT: The injector control solenoid valve is located below the pump, behind the support that is attached to the high-pressure section. It is secured with 2 screws using a 30 Torx key, and after loosening the screws, it can be pried loose with a small screwdriver and then pulled out.

hello

Thank you all for your help.

For now, I've simply tightened the screws on the lid of the injection port distributor – and I've ordered the seals.
Since I put it on, the thing has been completely dry, so I'm not going to do anything else for now.

Just in case, I have the seals and I will replace them.

Sure, here's the translation:

"thx"

Sure, here is the translation of the text from German to English:

"Hello"