1,9 Tdi läuft nach Komplettüberholung nicht richtig | Posts 16+

@roadrunner505,

In my opinion, the engine knocking sound you're hearing is likely caused by a valve sticking in its guide.
The piston pushes it back into the valve seat, or there is a faulty hydraulic lifter.

Regarding the computer, I'd say with a fair degree of certainty that it has a hanging issue.
"There's an issue with the valve, but have the valve drive checked."


best regards, jose

Nice idea, thank you for that.
"But that would mean that the cylinder where the valve isn't sealing doesn't have any compression, and the car would only be running on three cylinders. You would definitely notice that very clearly when idling, right? Also, I heard that the distance between the piston and the valve is so large that the piston couldn't push it closed (suggestions for improvement welcome...)"

The idle speed is relatively normal, except that the RPM occasionally fluctuates from 903 to 880.

Where can I get the valve timing checked?

P.S. The wires connected to the magnetic switch are correctly connected.

@Roadrunner505,

It's all imaginary, of course, and you should compare the car to the one that...
The engine has been overhauled.
Imagine that after the working stroke, the camshaft opens the exhaust valve and...
The piston moves from the bottom dead center (BDC) to the top dead center (TDC) to "expel" exhaust gases, but now the exhaust valve is stuck.
In this situation, the valve remains open because it is held open by the camshaft and is not pulled back into its seat by the valve spring before the piston reaches top dead center (TDC). Consequently, the piston pushes the valve further into its seat.
As the piston moves from Top Dead Center (TDC) to Bottom Dead Center (BDC), it draws in and compresses the air-fuel mixture.
So, the engine is running on all cylinders.

I also don't understand how you end up with work like that, or whatever the reason may be.
Why didn't you immediately take the car back to the workshop?
Unless you did the work yourself, you should probably give it a try sometime.
Let the workshop run.

The valve drive can be checked by any workshop.

Also für mich hört sich das Geräusch auch wie (mindestens) ein laut klappernder Hydrostössel an. LasLet's check that out.

Regards,
Matte.

jocasfe wrote:

@Roadrunner505, Consequently, the piston pushes the valve into its seat.

I've now discussed this theory, but I was told that there is always a gap of 1-1.5 mm between the valve and the piston. This would mean that the piston cannot completely close the exhaust valve, which would result in compression loss. However, the compression is good on all cylinders.

I also suggested looking at the lifters, but apparently that sounds different. The noise we're trying to identify seems to be coming from lower down in the engine.

I know, it all sounds very strange now, and especially like a crankshaft bearing or something – but we've checked the crankshaft and connecting rod bearings twice, and haven't found any play.

Are there any new theories? As I mentioned before, thank you very much for any suggestions.

Were the pistons mounted correctly?

Best regards,

SD16 wrote:

Were the pistons installed correctly? Regards

.

I already asked the guy who assembled the engine. He said he was sure. He mentioned that you couldn't install it backwards on this engine because there's a nozzle for cooling the piston with oil, and it wouldn't fit properly if it were installed incorrectly.

P.S. I've created some new sound files; they have less background noise.
The first recording was taken from inside the car, on the driver's side, and the second one was taken from the front bumper. Although the second recording is a bit distorted, you can still hear the idle quite well. I don't think that noise is present yet in that recording...

Okay, guys. I'm officially at my wit's end.
I had another fuel injector replaced yesterday because it wasn't working optimally and was opening too early. The car runs a bit better now. I routinely logged the current values, so please take a look at this .
I mean, the values mentioned above in the thread are only two weeks old. And with the new ones, I don't even know where to start: Mass airflow sensor readings are catastrophic - soot is causing partial blockage, turbo pressure is completely too low, the displayed requested fuel injection amount at idle is 0, and the displayed fuel injection amount at idle for group 1 (not included here) is still 8.8mg...

What is this now?

" color="red">Bitte keine Links zu externen Dateihostern! a) nerven die zusätzlich notwendigen Klicks, b) Wartezeit, Werbebanner/Werbepopups und notwendige Registrierungen, c) ist nach einiger Zeit die Datei weg und das Thema für andere Leser nutzlos!

Bitte nutze 'Attachment hinzufügen' bzw. das Upload Forum hier.

"I would like to address the issue of boost pressure first. This has been a recurring problem from the beginning of this thread. The regulation itself hasn't worked for the past two weeks either. The insufficient air mass is known to be a consequence of the low boost pressure, so let's not focus on that for now."

If the turbocharger pressure is correct, you still need to adjust the fuel injection amounts.
Did the workshop perhaps cut corners during the installation of the charger? Was the new charger definitely okay?

What else I've noticed is:
The target values for the turbocharger boost pressure are only at a basic 90 horsepower level, and I'm not sure what changes the chip tuner made. It's a strange chip...

Current status: I've at least found the error related to boost pressure and mass airflow sensor (MAF) values. I relied on a specification from VW in the ET** system, and it seems the connection of the magnetic valve is described incorrectly there.

Okay, I received another connection diagram, and now I have the following values for groups 3, 8, and 11 (see Appendix 1). Since the airflow rates are still quite low, I re-examined which groups are still showing issues. That's when I noticed group 1 (see Appendix 2). Does anyone have any other ideas?

It seems a diode was installed as a fake mass airflow sensor (MAF), and the tuning chip is active.
The boost pressure is achieved to some extent, but still too late.

It seems to me that around 3,600 RPM, it starts hitting the soot limit, and apparently, even the slightly too low boost pressure is enough to cause this.

With that amount of fuel injection, it should run really well.

No, no you - The LMM (likely referring to a machine or process) ran completely normally, without any bypasses or anything else.
But as you mentioned, with the correct fuel injection amount, it should actually run quite well. However, it doesn't.

Here's a question about the MFA's strange fuel consumption readings: Could it be that the control unit is only *thinking* that so much fuel is being injected, but in reality, it's not actually injecting that much?

That would also explain why my average fuel consumption, as indicated by the car's onboard computer, of over 9 liters is not realistic.

Perhaps it would also be interesting to ask: Where does the engine control unit (ECU) get the values for the amount of fuel injected and the consumption?

I'd also like to mention this again: With the 205 injectors and the chip, I should definitely be leaving a noticeable trail of black smoke behind me. However, there is absolutely no smoke at all. Not even at 4500 rpm in second gear, or at night under the lights of the car following me...

The injection amounts are just calculated values; a real-world measurement of the amount injected is not taking place. Therefore, a misadjusted or defective pump could inject significantly less fuel. I hadn't fully considered that.

I was surprised by the mass airflow (MAF) values because, even with a boost pressure well below the target at 1900 rpm, it's already hitting the upper limit for air mass. That's why I suspected a faulty sensor, especially since your readings in the last log were rather poor.

Unfortunately, the problem with boost pressure still persists. It only builds up enough pressure to reach the target value starting around 2,400 RPM. Ideally, it should be reaching that level by at least 1,800 RPM. The duty cycle of the turbocharger control seems to be constantly at its maximum, and even then, the turbocharger only briefly reaches the target pressure. Still, it's 500 RPM earlier than in the previous logs. A correction of the VTG (Variable Turbine Geometry) rod might help if the entire charge air system is 100% airtight (!). Ulf wrote a technical article about this topic.

I don't understand why you seem to be logging data alternately with and without a tuning chip. This makes it much harder to pinpoint the cause of any problem. A systematic search becomes impossible if you change parameters in every possible way. Why don't you keep everything at the standard settings until the issue is resolved? That way, you can also compare your data more effectively with other cars or tables.

@ Roger

As far as I know, the Roadrunner has a 1Z engine, so it's not related to VTG.

EDIT: Yes, it's a Passat with the 1Z engine (/viewtopic.php?t=9770&highlight=).

At the very least, the "serial logs" with a maximum torque of 35.4-35.2 exactly match what's seen in a 1Z engine (specifically, a 90 HP wastegate VP TDI).

To the best of my knowledge, the ALH engine (also with 90 horsepower, but VTG) has a maximum limit of 35.8 mg.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

What type of boost pressure sensor is installed in the 021 AT?

Is it an MSA12 or an MSA15? (Plastic or metal housing?)

It might still have the 2-bar sensor installed, which means it can't actually regulate the boost pressure to 2 bar (absolute).

I have the 021 AF (MSA12) model, which is supposed to have the 2.5 bar sensor.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

021AT is an MSA15 with a 250 kPa sensor.

Best regards,
Rudi