Passat AFN: ESD 2nd Cylinder, Still Air?

Hello,

I haven't found anything directly related to this problem, although I did find information about bleeding (airing) systems, but nothing quite like what I'm experiencing.

Vehicle: Passat 3B AFN, manufactured in 1997, model year 1998, with almost 500,000 km.

Here's a brief background:

I drove for a long time with a faulty EGR valve in the area of the MSW (Motor Software System), which very likely caused the timing belt to skip a tooth when the engine was turned off (no idle stop valve). Unfortunately, this went unnoticed.

On the next attempt to start the engine, which took a very long time, the timing belt finally broke.

Result: New valves, new hydraulic lifters including the head gasket, and a timing belt kit. At the same time, the entire ESP (electric steering pump) was disassembled and all seals were replaced.

Okay, I'm almost there and I'm starting to bleed the system. I took an old bottle, attached two hoses to it – one connected to the return line on the injection pump, and the other going into the bottle's opening. Let's get started... it's working great. Diesel is flowing into the bottle.

Now, let's get to the problem:

The fuel lines at the injectors were disconnected, and diesel is leaking from all of them. However, when slowly tightening the fuel line from the 2nd cylinder, very fine bubbles are coming out, almost like foam.

The engine runs wonderfully with the retaining nut not fully tightened (except for the bubbles and the diesel fuel that leaks out), but as soon as I tighten the nut, it stops running... which makes sense, because of the air.

The little bubbles just won't stop... I've had it running for three minutes already...

Does anyone have any ideas?

Best regards,

Hello,

Quote:

The engine runs wonderfully with the retaining nut not fully tightened (except for the bubbles and the diesel that leaks out), but as soon as I tighten the nut, it stops... logically, because of the air...

No, that's not logical. Something is either assembled incorrectly or is defective. The engine doesn't care whether fuel is being injected into one of the four cylinders or not; it will simply continue running on three cylinders.

Are the pressure relief valves (located between the manifold and the injection lines) defective? Is the injector holder assembly, specifically the part where it bottoms out when tightening the union nut, in good condition?

Best regards, Rainer.

Is cylinder 2 the one with the NHG?

The NHG is cylinder 3. And if it were, it wouldn't matter.

Hi,
A faulty pressure relief valve would initially only cause instability in the system. The pressure relief valves are only meant to maintain the residual pressure in the line.
However, it would be a good idea to swap the nozzle from cylinder #2 with, for example, the one from cylinder #1, and see if the problem moves along with it.
The devil may be in the high-pressure section.
The venting method is rather unconventional, and I don't understand why a leaking MSW (multi-stage water pump) would cause the timing belt to jump.

What exactly did you do to the pump?
hg
Herbert.

Hello Nash.

For testing purposes, please remove the oil feed lines from the ESP (Electric Stability Program) circuit.
Simply put it in a jar or bottle.

When I replaced the injectors on my Golf 3 AHU.
Was the sealing in the nozzle block slightly flawed?
He forced the exhaust gases from the combustion chamber into the leak oil line.
This air then re-entered the ESP.
After loosening the cap nut, air bubbles and foam came out.

Just a thought...

Greetings,
Georg.

Okay, I'll replace the nozzles this afternoon, but I need to get the copper rings beforehand.

I can also review all the GDVs again.

I didn't have anything else on hand to bleed the brakes, so I had to do the whole thing on the street.

The diesel leak wasn't just coming from the side of the engine block, but also from the front, which I previously considered very unlikely. And there, the diesel is dripping onto the timing belt from the crankshaft pulley. It has always dripped onto the road when idling and stationary.

I completely disassembled the pump in the basement, all the way down to the vane pump. I followed the instructions available on this forum. I also made sure to be as clean as possible during the process. There were no problems during the reassembly.

I'll also try that tip about the oil drain lines.

Best regards,


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

"Addendum:"

Hello again.

I wasn't able to replace the nozzles today because they didn't have the copper sealing rings in stock; they'll be available tomorrow.

I've examined the GDVs, and you can see through them; it's clear that light passes through.

That shouldn't be the case, right?

Swapping the GDVs (presumably referring to some electronic components) among themselves didn't resolve the issue, which wouldn't matter anyway if they were all faulty. Fortunately, these are still the original components from the factory.

Best regards,

Addendum 2:

Today, I swapped cylinders #1 and #2, and of course, the foam came out of the injector nozzle on cylinder #1. So, the problem is moving with the cylinder. The set of injectors has only been installed for 80,000 km, and they are typically replaced every 200,000 km.

What could suddenly fail in an injector today? I didn't handle it roughly during installation or removal, and I only soaked the nozzle tips in diesel to loosen any carbon deposits.

Okay, I'll order a set of new nozzles tomorrow and then let you know how the machine is running.

Here's something else, just for reference: I couldn't read the value before, but what should the fuel injection amount be set to at idle when shifting the MSW (presumably a control module)? Are there any typical values based on mileage, for example? I found the specification in the table with the target data for the measurement blocks, but it's a pretty wide range...

Best regards,

Hello,

I have three ideas right away:

Quote:

What could possibly fail in an ESD from one day to the next?

a) When "loosening," if you turn it too much counterclockwise, the locking nut at the front will come loose.
b) Dirt may have been introduced, causing the nozzle to either not open at all or to remain open constantly.
c) Allow the nozzle holder assembly to drop, landing on the nozzle tip.

Best regards, Rainer.