V6 BDG Kompression im Keller, Grund? | Posts 16+

Hello everyone!

TDI-GTI-4-Motion wrote:

... It was measured with a warm engine, but since that wasn't done, it doesn't really tell us much. ...

Before we go around in circles completely unnecessarily another 15 times...

Perform the compression measurement exactly as described in the RLF!
...then it makes more sense to philosophize.

Otherwise, as mentioned many times before, the wear limit is 24 bar *WARM* (!!) with a *SIMULTANEOUS* maximum deviation of 5 bar between the highest and lowest measured values *WARM*.

Best regards from Munich!

So, the engine is starting poorly because the pressure difference between the individual cylinders is too large, even though the compression in each cylinder is sufficient to safely start the engine?


If I now remove the covers and the camshaft lobes show no signs of wear, and the camshaft itself shows no signs of torsion, what should I do next?
Checking the roller lever is straightforward, but what about the hydraulics?

Set the cam to the top dead center (TDC) position and measure the distance between the cam and the rocker arm.

edit: DieselBär, the workshop measured a low temperature because the engine didn't start easily even in the summer.
But shouldn't the compression be even better than 24 bar in the summer, with a "cold" machine?

Hi again!

What specifically are you concerned about right now?
1.) To determine the wear condition of the engine?
1.1) Is the cause of the compression loss being ruled out?
-> Perform the compression test AFTER the RLF (Relief Load Function) and only when the engine is warm.
If there are no anomalies, then you can repeat the test in cold mode for systematic troubleshooting, but measuring it in a cold state initially doesn't really provide any useful information.

As the editor mentioned, I would leave the assessment of the NW (Northwest), Hydros, etc. to a specialist, as it requires some experience.
Please quickly recover the amount for this, before you unnecessarily cause someone trouble .

Best regards from Munich!

Hi,

Actually, all I want is for the car to start properly.
It's clear that the compression is likely the cause of the problem.
Now I want to know what the problem is.

The car remained in the workshop for a full six weeks.
I wanted to rule out the VP44 because it's a relatively new component.

After 2-3 weeks, I should be able to pick up the car. The temperature sensor has been replaced (apparently, it was showing incorrect readings).
It should work perfectly again...

As soon as we arrived at the farm, the boss was standing outside and said the car wouldn't start.
He then used starting fluid to get it going... I always managed to start it myself.
I think the battery was probably discharged.

Then it said, "had to leave it here," probably because the pump was broken.
Three more weeks off the road because the Bosch service apparently messed up when testing the pump, blah blah.
Result: The pump is functioning correctly.

Then, a compression test was performed, a faulty glow plug was drilled out, and a new battery was installed for testing purposes.
You already know the results of the compression test.
Well, now it's December 19th, and I'm still stuck in the Allgäu region until Thursday, and I'm racking my brains trying to figure out what's wrong .


I don't think I trust that repair shop with my car anymore.

I'm going to remove the valve covers and perform another compression test myself. I'm also going to pressurize the cylinders with compressed air to see where the air is escaping, if anywhere. I'll get back to you after Christmas.

I'm bored and looking for suggestions on where to start.

Sorry for the inconvenience .

Hi,
Here's a thought.
- According to the table in this forum, the BDG has a compression ratio of 1:18.5.
- The 1st gear has a compression ratio of 1:19.5.
The wear limit for compression is 19 bar for the 1Z model, while the new value is 25-31 bar of overpressure (Relative Load Factor).
Why is the wear limit so much higher at the lower compression ratio of the BDG, at 24 bar?
It seems strange to me. Can someone consult with the RLF regarding the BDG?
hg
Herbert.

RLF says:


BDG: New: 27...33 bar overpressure. Wear limit: 24 bar overpressure.

AHU: New: 25...31 bar overpressure. Wear limit: 19 bar overpressure.

Therefore, the RLF does not correlate with the compaction .



Best regards, Georg.

If anyone has Motor-Talk:

http://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=681731

Does that also come from the RLF?
"For some reason, it says 17 bar..."

Hi,
I had also seen the reference to "17 bar," which is why I asked the question, but the quote from Georg in the RLF (presumably a document or source) should be quite clear.
hg
Herbert.

It seems the RLF contradicts itself in several places.

Now that an official source has confirmed a lower (compared to the four-cylinder engines) value of 17 bar, be happy about it!

Have you ever considered the possibility of a too-low starter motor speed, regardless of the battery quality?


Best regards, Georg.

Well, but you don't really see much about "17Bar" online.
I'm not sure how old this information is.

The Bosch workshop also said that the pressure should not exceed 24 bar, and I don't believe they would provide unreliable information.

I've also been thinking about the starter issue, but I haven't tested anything yet.
A new starter motor was already replaced because the pinion gear was constantly engaged.

It's possible that I have a resistance issue in the crimp connection leading to the starter motor, although recently, after starting the engine, I saw a starter speed of 350 RPM in VCDS.

It doesn't make a loose or rattling sound when turned.

It wouldn't really align with the LLR values after launch.
They're already running on two cylinders within the first minute, even though they're supposed to be measured only when the machine is warm...

Are there any known cases of IHU waves exhibiting self-rotation?
So, is there a torsion in the pipe?

Perhaps the wave could deform from the camshaft drive towards the injection nozzle, thereby altering the valve timing for cylinders 4 to 6?

Just a thought, I haven't read anything like that before.

Hi,
two conflicting repair manuals? They may change, but to such a fundamental extent?
- @Exciter - I'm interested in the thread on motortalk. Could you please provide a link to it? I knew about the 17 bar from another source.
- @Georg - I assume you have an original RLF (from the Volkswagen Group). Which vehicle and what production date?
hg
Herbert.

I unfortunately haven't been able to find the link quickly.
Perhaps Audi adjusted the values downwards due to claims of good faith.

I also found the 17bar specification in an Italian forum. Where did you get this value from?

Hey everyone!

"Wash me, but don't get my fur wet!!"

Wouldn't it be simpler to now perform a compression test according to RLF while the engine is warm, and then perhaps realize that it doesn't really matter whether it's 17 or 24 bar, because the values are anyway higher than that?
This has now been suggested 6 times (or so), but persistently overlooked.
If you do not want to have the proper compression test performed (or performed by someone else), and/or if you absolutely want to inspect the NW drive yourself, please let us know.

Dear exciter, please don't misunderstand me...
Personally, I don't see any way to solve your problem right now, but only fundamental philosophical approaches .

We can certainly discuss the incandescent light bulb regulation, but whether that will allow YOUR 6Ender (= not mine! ) to start better remains, equivalently, an open question .

Best regards from Munich!

You are right, Dieselbear .
I'll test the compression again while it's warm, and then I'll need to see what else needs to be done.

As I mentioned, I haven't had the opportunity to work on the car in the past few months, so I've been looking for ways to locate the problem beforehand.

I think I've become a hypochondriac during this training course .

No problem .

Either do it yourself or have someone else do it, then we can better help you!

Best regards from Munich!