Drehzahlruckeln ab 3300 u/min AVF, mit log-file! | Posts 16+

schewisch wrote:

I noticed on your Polo that you're tapping into the AGR valve. It looks good, but could I quickly find another place to tap into the LD (likely referring to a pressure line) for testing, without having to drill a hole in the "sackloch" (likely referring to a specific area)?

Perhaps by using an injector needle on one of the thick pressure hoses before the AGR valve. However, you will likely have difficulty permanently sealing this small hole without the cannula, and a new clip flange hose fitting costs an outrageous amount of money .

You replace the tapped AGR valve with a regular screw, applying some sealant, and that should do the trick.

hello,

Does anyone know the part number for relay 109 for a Passat 3BG manufactured in December 2002 with engine code AVF?

Unfortunately, I can't check the car myself at the moment. According to Volkswagen, my Passat doesn't have that relay. However, they can't find any other relay either. Well.

@Ulf: I now have a pressure gauge here. Unfortunately, I can't find one that measures from 0-2 bar; I only have one that measures from 0-6 bar, but that will be okay. I'm using a PU6 hose with an inner diameter of 3.8 mm. That should be enough to prevent any vibrations from being transmitted, right?

Best regards, Schewisch.

schewisch wrote:

As a hose, I use a PU6 with an inner diameter of 3.8 mm. That should be enough to prevent any vibrations from being transmitted, right?

I wouldn't bet on it.
Have you read the tips on pointer damping in the LDA-FA?

hello,

@ulf:

Yes, I have read the tips for LDA (Low-Density Ammonium) damper adjustment. Of course, I forgot to mention that I am installing an adjustable flow restrictor before the pressure gauge. I am familiar with these vibration problems from industrial pneumatics. This restrictor simply reduces the cross-sectional area. I am using it to try and achieve a meaningful level of damping. In control engineering, one would say to bring the damping factor close to 1.

Only the relay 109 is missing...

edit: ok, I think the relay we're looking for is number 167.

Best regards, Schewisch.

ulf wrote:

germa wrote: The error was a defective/loose speed ring on the crankshaft. . . It really took me a while and a lot of frustration to find the error back then. In the end, the customer went to VW and received a new engine as a goodwill gesture. Wow, you have to really think outside the box to come up with that. Did the problem only start "sometime" ago (like with Schewisch), or was it present from the beginning and only delayed beyond the warranty period as a matter of "state of the art"? @schewisch: It would be interesting to see if the drops in LD (Low-Density) are also visible on an LDA (Low-Density Array).

According to the customer at the time, the problem started very gradually and became increasingly severe, and it even disappeared completely from time to time.

I reported issues such as a clogged VTG (Variable Turbine Geometry), leaks in the vacuum system, and a faulty EGR (Exhaust Gas Recirculation) valve.

Of course, everything has been checked, with many test drives and using a diagnostic tool, and almost always there are these dips in performance around 2850 RPM to approximately 3350 RPM. It ran smoothly both above and below that point, sometimes with a wider range of problematic speeds, and sometimes with a narrower range.

AGR system cleaned, all vacuum hoses replaced, and the electro-pneumatic converters for both the AGR and the turbo were replaced as a precaution (you never know!).
Before I started disassembling the turbo, I stopped and called a friend who works at VW to ask if he had heard of this problem. Two days later, he called me back and told me about the sensor. He only found the information after searching for hours in VW's internal network. He also replaced the engine!

hello,

So, it wasn't relay number 167 (fuel pump and MSG) either. It's still going strong...

bashful

hello,

Short update:

- Checked the turbocharger system for leaks, everything is okay.
- Control line replaced for the injector elements.
- Checked the speed sensor... all okay.

I also installed a boost pressure gauge. I'm using a simple industrial gauge from Festo, with a range of 0-4 bar. Throttle adjusted... working very well.

I went for a drive, and lo and behold, the shaking/jerking was gone. I hope this proves to be true on a longer journey tomorrow.

"On the boost pressure gauge, I can see that the turbocharger overshoots briefly and then settles at 1.56 bar under full load. The overshoot goes up to almost 2 bar. It seems a bit high at first glance, but it only lasts for about 1 second." If at all.
But I think I need to check the VTG first. Are these swingers okay?

By the way: Can anyone recommend a laser diode alignment tool that integrates well into an indoor environment? With lighting?

bashful


edit: No more stuttering! It was the darn wiring harness.