AVF TDI im Passat 3BG: Kaltstartproblem | Posts 16+

Hi, they are just regular small black cable ties. I'm going to change the filter now.

Greetings.

I hate cable ties. I usually replace them with regular hose clamps (e.g., for cooling systems), or with extra-tightening hose clamps if the lines are thinner and the seal is critical (e.g., diesel lines).

Okay, ich verstehe. Bitte gib mir den deutschen Text, den du übersetzt haben möchtest.
/viewtopic.php?t=12040&highlight=rounded

Damn. I have the feeling that after a cold start and during the warm-up phase, especially when idling (constant throttle and medium RPM), it's shaking *very* slightly and *very* gently. Maybe it's just my imagination, but I'm not entirely sure. It's probably related to the problem, right? Could it be the O-rings of the injectors? Can leaky O-rings also affect the starting behavior that much?
I already have the KS-filters here, the check valve will arrive tomorrow (order). No one has been able to tell me, not even the master mechanic at the , where the check valve is located on my AVF. His comment was: "somewhere between the pre-pump and the tandem pump." Haha, that was really funny.

"Hey, how much does it typically cost to replace the O-rings on a ? Do you still need to adjust the pressure settings (PDEs), even if you're just replacing the rings? How many O-rings are there per PDE, actually?"

Greetings.

Hello!

I have some new, potentially helpful, insights. I changed the diesel filter on Thursday. It was very easy and without any mess. However, I quickly read the error memory beforehand, and I got the following incredible message:
"popped up" or "appeared" (depending on the context)
"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
VAG-COM Version: RKS 607.3-UD

Control unit part number: 038 906 019 GQ.
Component and/or version: 1.9L R4 EDC G000SG 1524.
Software Coding: 00002
Workshop code: WSC 05xxx
Additional information: WVWZZZ3BZ2E42xxxx VWZ7Z0B499xxxx
"One error found:"
18263 - Data bus drive: Software status monitoring.
P1855 - 35-00 - -

Self-test: 0 0 X X X
"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Es ist ein wunderschöner Tag, um spazieren zu gehen oder ein Picknick im Park zu machen. Viele Menschen genießen das gute Wetter und verbringen Zeit im Freien."

I have to mention that I replaced the battery again, and since then I haven't looked at the memory. Could this be related to that, or rather to the problem itself? The error message means absolutely nothing to me.

Now, let's get back to the problem:
After replacing the diesel filter, I observed how it started. Initially, it started immediately because there was still fuel between the filter and the injectors. Then it stalled. So far, so good. Then I started it again, and it started as you would expect from an empty filter: long cranking, sputtering, and gradually all the cylinders fired, running roughly for a short time before stabilizing completely. So, the starting behavior (unfortunately) has nothing to do with the actual problem, which is why I can't imagine that the problem originates from that area. What I find strange is that since the filter change, everything has been quiet so far, meaning the problem (hasn't) reappeared yet. But I'm not comfortable with this peace, because the temperatures are simply too high.

Then I experimented a bit with the G28 and the G40 to see if I could simulate the problem by disconnecting the connectors. But unfortunately, it didn't work. If you disconnect the G28 and try to start the engine, it cranks normally, but it doesn't start at all and stores the error message "G28 no signal" in the memory. As I said, my problem isn't a normal starter motor cranking sound, but it's accompanied by a REGULAR (!) ignition noise and shaking! Then, I disconnected the G28 while idling, and the engine immediately stalled with the same error message in the memory. With the G40, it was similar. Starting without the G40 -> the starter motor cranks normally but for a longer time, but the engine still starts. Error in the memory: "G40 camshaft position sensor no signal".
The engine was warm during all the tests. I'm not sure if that's significant, or if the engine needs to be cold for the tests to be accurate.

I've also created some performance logs and an idle speed control log to see if you can spot anything suspicious, even when the engine is warm. I'll put the files together, organize them, and then upload them.


Thank you very much for your continued help, and please don't let me down.

Greetings.

Mike3BG wrote:

I came across the following incredible message. "popped up" or "appeared" (depending on the context) "One error found:" 18263 - Data bus drive: Software status monitoring. P1855 - 35-00 - - I must add that I changed the battery back and haven't looked at the memory since then. Could this be related, or is it more likely related to the problem itself? The error message means absolutely nothing to me.

Hi,

I'm familiar with that message; it appears on my Polo every time I disconnect the battery (usually after doing some tinkering). It's stored in the system's memory.
It disappears again shortly after (I haven't counted yet how many times this has happened).

It seems to be normal in that regard, and unfortunately, in my opinion, it has nothing to do with your starting problem.

It's a shame it wasn't just air. I would still wait to see if it comes back. Maybe you'll get lucky. But in my opinion, it was worth a try...

Question for others: Can PD (partial discharge) seals be detected using a compression test?

I would, if it happens again, like to have a compression test done. If you have anything done to the brake discs (PDs), it's going to be quite expensive .

Herr Antje wrote:

Question to others: Can PD seals be detected using a compression test?

Barely:
A particulate diesel filter (PDF) is located in 4 different areas, with one sealing element between each: combustion chamber - diesel pre-injection - diesel return - valve cover area.

A compression test can only reveal major problems with the lowest sealing ring in the combustion chamber.

More importantly, replacing the two black hoses leading to the coolant reservoir with clear hoses can be very informative: If there are more bubbles in the return hose than in the supply hose (in my Polo, I didn't see any bubbles at all), then one of the cylinder head gaskets is likely defective.

ulf wrote:

A compression test can only reveal major problems with the lowest sealing ring in the combustion chamber.

With poor compression and low temperatures, it's also possible that the car might have trouble starting, right? That's why I'm asking.

If the starter speed, glow plug system, injection timing are correct, and there's no air in the fuel lines, then it can only be the compression or the fuel injectors that are the problem.

The compression should be the easiest and cheapest thing to check. Installing a clear hose isn't that expensive either. If everything else is okay, you'll probably have to start looking into pressure regulators (PDs).

@Mike3BG
I think that many people are running out of ideas. I personally can't really help you either. That's really a piece of .

Hello everyone!

I somehow don't believe it's a fuel line issue, because the starting behavior was completely different from what it is in a fault. Namely, during the cranking, there's sputtering, coughing, and a slow emergence from below. My problem is that the starter motor actually spins "normally" quickly, and with each starter motor revolution, there's also the sound of the ignition (duck duck duck duck duck duck duck). No sputtering, no coughing! Only the shaking, which is also clearly noticeable with each starter motor revolution, is present. It's like an old tractor that's chugging along but running smoothly. I also don't understand it. I would like to record it, but right now it's working, and at these temperatures, it's also possible that the problem only occurs briefly (a short jerk/lurch when starting), so that you might not even notice it. I fear that I will have to live with this until autumn/winter. Then the whole thing will probably start all over again.

To the extreme tech experts: Does anyone know under what conditions the G28 error code appears in the system memory? If it's actually triggered by a jerky starter motor speed (i.e., a secondary fault), then it could be caused by anything. Personally, it seems that way to me. It's almost like a "stuttering" start, but it's so fast that the starter motor is working against the ignition. Is something like that even technically possible? Could the dual-mass flywheel (DMF) potentially counteract this during starting? Is something like that fundamentally possible?

Kurze Frage: wie kann ich den Förderzeitpunkt beim PD kontrollieren? Vielleicht paßt ja ev. was nicht mit dem bei 55 tkm gewechselten Zahnriemen? Wenn der Motor nicht läuft kann man den ja nicht mit VAG-COM testen, oder? Und warm sagt der Wert auch weniger aus, oder? Welcher wäre das denn überhaupt? Wo fCan you find it?

Greetings.

Hello, it's me again!

Today, he fixed it again, but only for a very short time . So, it wasn't the diesel filter either . I haven't been able to replace the check valve yet, because I haven't found it . However, I don't think the problem is coming from that direction .

Could someone please take a look at my logs? I can't see anything unusual, but maybe you can . At least the LMM (lambda measuring module) seems to be working correctly, or (bold line in MWB 10+11)? All logs were taken with the engine at operating temperature, without the air conditioning or other consumers running, and under full load (approximately 2000-4000 RPM), except for the LLR (lean/rich mixture) control (which is logical). The timestamps 1 and 2 always indicate the full load phase.

Greetings.

Hello!

Does anyone have any comments on my monthly work report? Well, never mind, but I think it should be okay.

Can someone please tell me where I can find the power supply relay for the engine control unit (ECU)? It's not in the fuse box near the ECU. There's only one black relay there, and I think that's for the glow plug system. But where is the other relay located?
I still haven't found the check valve. I wonder if it really exists on the 'new' AVF model?

Thank you.

Besides, the door lock also broke. After all, there's nothing else to do }.

Greetings.

Hi,

Are the values from G62 checked even during the error condition?

Are the logs not being created during the startup process?
If so, what's the point of logging the boost pressure during the starting process?

Answers to the rest of your questions can be found using the search function and in specialized articles.

Best regards, Rainer.

Hello Rainer!

No, of course, the logs are typical full-load logs, and one is an LLRR log. They are intended to determine if the vehicle is otherwise completely okay. The underlying idea is that if it shows even slight signs of abnormalities during normal operation, it could be a clue to the starting problem, which might "linger" and only be visible in the logs, with the driver barely or not at all noticing it while driving.
As I said, to ME, as a layperson, it looks normal. But maybe you'll notice something that I don't see.

I haven't logged G62 in error cases yet, as it doesn't really make sense at the moment. It probably only occurs about once a month (due to higher temperatures).

Before I start tearing things apart: Where is the gray power supply relay for the engine control unit in the 3BG TDI? Is it on the relay panel in the footwell? I've already searched before, and someone mentioned the electrical box in the coolant reservoir. I was in there yesterday, but as I said, there was only a black relay, and I think that's for the glow plug system.

Thank you.

Greetings.

Hello.

"Hmm, my AVF engine in my Audi A4 Avant 2003 sometimes does the same thing, in my opinion, especially when I'm driving uphill (which could indicate a vacuum leak). I also hear that "tuk tuk tuk" sound *g* – that's the combustion cycle in my case, from the second cylinder, which works fine every other revolution, but the rest doesn't... hmmm. I've suspected the camshaft sensor, but if that were the problem, the second cylinder wouldn't be working correctly either. Well, as long as it doesn't get worse, I won't do anything else."
Sure, here's the translation:

"lg" is a German abbreviation that stands for "liebe Grüße," which means "best regards" or "warm greetings." It's commonly used in emails, letters, and other forms of communication to express affection or goodwill.

Install clear tubing properly and securely into the fuel line(s) and check if larger air bubbles or foam are visible in case of a fault.

Best regards, Rainer.

"I've been using clear inlet and outlet hoses for a year, with very few or no bubbles. The problem with the clear hoses is that they turn black over time! When I installed my auxiliary heater, I had to remove the fuel level sender, and to my dismay, I discovered that the sender, which is supposed to be made of white plastic, is covered with a thin black film. The entire tank is coated with it, but the fuel itself is clean! Apparently, it's normal for a small amount of oil (engine oil) to leak into the fuel system (from the O-rings of the common rail injectors). I'll check the fuel tank of a friend's Golf at ATD sometime *gg*. Okay, let's move on from that topic..."
almost no air bubbles, but every 10 starts, it starts poorly .