DPF und Motorkontrollleuchte leuchtet, 2.0 CR TDI | Posts 24+

dieselschrauber · 07-09-2019, 8:23 Subject:

Because it's possible that previous owners may have modified it (if applicable).
hg
Herbert.

07-09-2019, 10:14 Subject:

"No, that can't be right. I've driven this car for 180,000 km, and before that, it was always serviced at VW because it was a leased vehicle."

dieselschrauber · 07-09-2019, 10:20 Subject:

I'm just trying to help you before you start replacing parts. The simplest things to do are visual inspections and reading out values.
How would you tell if an ESD (electrostatic discharge) device is defective?
hg
Herbert.

08-09-2019, 10:41 Subject:

Herbert wrote:

I'm just trying to help you before you start replacing parts. The simplest things are visual inspections and reading out values.
How would you tell if an ESD (electrostatic discharge) device is defective?
hg
Herbert

Yes, I know that, and I haven't been using diesel for very long. I've always been a gasoline fan. I once did a test drive:

08-09-2019, 16:40 Subject:

Hi,
However, the values of the LLR have changed significantly since your last publication.
What is also noticeable is the clearly negative values of the rail pressure calibration for all cylinders. The injectors spray very easily (open very easily). I wouldn't say they are "incontinent" (yet), but it would explain some things.
Perhaps a colleague here knows more.
Are the correction values entered in the MSG (Main System Generator) the same as those embossed on the injectors?
hg
Herbert.

09-09-2019, 4:56 Subject:

Good morning Herbert,
I haven't checked the values yet. I'll do that this evening. I'll also measure the return flow. Also, I've noticed that it smells like exhaust fumes. And at around 1800 RPM, it makes a strange noise. It sounds like a piece of metal is loose and hitting something, but I can't find anything that's loose.

09-09-2019, 8:16 Subject:

Frankbe wrote:

And at approximately 1800 revolutions, it makes a strange noise. It sounds like a piece of metal is loose and hitting something, but I can't find anything that's loose.

Release bearing of the clutch?

09-09-2019, 12:22 Subject:

The release bearing is unlikely to be the problem, as the clutch has only been in use for about 70,000 kilometers. Also, the noise comes from the top, regardless of whether the clutch pedal is pressed or not.

2019-09-09 17.25.51.jpg

Okay, now let's talk about the return quantity.

dieselschrauber · 10-09-2019, 3:28 Subject:

Nice, but without any volume specifications, measurement duration, or speed during the measurement, it's just aesthetically pleasing.
Let me tell you what I think.
- Vehicle purchased with 90,000 km (approximately 56,000 miles), with previous engine repairs likely unknown.
- White smoke upon regeneration indicates incomplete combustion, likely due to excessive fuel injection.
- Problems with regeneration -> likely due to the old DPF, but excessive soot formation is probably also a factor;
- The oxygen sensor reports "too rich" -> indicating either insufficient air for proper combustion or an excessively high fuel injection volume.
- AGR and DPF clogged with soot -> possibly due to excessive AGR operation, or potentially a generally high soot content in the exhaust.
- Soot on the exhaust side -> The air-to-fuel ratio is incorrect, indicating a faulty injection system or poor compression.
- Significantly negative values in the zero-quantity calibration for all injectors -> worn nozzles, excessively high injection quantities (which cannot be corrected further), nozzles are dripping.
In the image, all the ESDs (Electrostatic Discharge devices) need to be replaced, and after the prolonged period of malfunction, the cylinder liners should be inspected for signs of melting.
Perhaps there was an exchange of ESDs (Electrostatic Discharge devices), and maybe someone tampered with the initial quantity matching calibration (IMA). That's why I suggested a quick check in that area.
By the way, the noise you're hearing could also be caused by a collapsed hydraulic lifter. Those are likely worn out at 270,000 km. I would check that immediately.
hg
Herbert.

10-09-2019, 4:50 Subject:

Okay Herbert, the measurement was taken over 6 minutes, and that was at idle. I did give it some gas at the beginning for about a minute to get it started. I've ordered some new injectors, and they're arriving tomorrow. Tonight, I'll remove the old ones and take off the valve cover. Then I'll take a look at how the valve lifters look.

18-09-2019, 20:07 Subject:

After changing the injectors, it's a little better. But only a little. It also doesn't run as rough anymore. And it starts up better again, but not like it used to.

dieselschrauber · 18-09-2019, 20:48 Subject:

And what have you recorded just now?
hg
Herbert.

19-09-2019, 5:09 Subject:

That was a log in a stand.

Herbert · 19-09-2019, 5:32 Subject:

Hi.

Frankbe wrote:

That was a log in the stand.

It seems to be an issue with the idle speed control. It could be a mechanical defect in the cylinder or a faulty fuel injector.

-> Perform compression test and inspect nozzles.

Best regards, Rainer.

dieselschrauber · 19-09-2019, 7:53 Subject:

It would be helpful if we knew what you did, and what you didn't do.

Which specific nozzles were replaced?
Were new seals installed?
Part numbers for the old nozzles?
Part numbers for the new nozzles?
Supplier and manufacturer of nozzles?
IMA values have been read and accepted by the control unit?
Were the learning parameters reset?
Was the fuel injection system bled?

And as for that:
What are the current values for the rail pressure calibration?
Are the hydraulic lifters okay?

hg
Herbert.