ASZ suddenly ceases.

Hello

My neighbor Sharan's car suddenly loses power while he's driving.
It is a Sharan 7M with engine type ASZ, manufactured in 2006.

The vehicle is jerking and not delivering full power, as if it's not getting diesel, or experiencing "misfires." Then, after about 2km or after standing for about 3-5 minutes, it simply stalls. It only starts again after trying to start it four times. Then it will at least run quietly in idle mode, for now.

The PD (Pulse Density) elements for cylinder 1 and 4 are outside the tolerance during idle operation. In some cases, it exceeds 3.0. This is also very noticeable during idle. However, this is not permanent. He swings up repeatedly and then comes down again to approximately 1.4.

The cable assembly to the PD elements still looks quite good externally. No cracks in the insulation.

I exchanged the spare pump for testing purposes. I still had one left over. No way.
The booster pump is also working.

When the engine control unit (ECU) fails, the error codes don't initially appear in the diagnostic memory. After about 30 seconds, I can then access the diagnostic memory.
However, no errors are recorded.

These are the things I checked quickly, initially.

I think that the engine control unit (ECU) might have a fault. This would explain the engine stopping. Or could the old PDAs also cause the engine to stop? Thought it was only affecting the younger generation.
Maybe you have a few more tips and advice.

Greetings
Bolzer

Quote:

I think that maybe the engine control unit (ECU) has a fault. That would explain the engine stalling

Is it the case that he shuts off after every start, after about 2 minutes, and then restarts?

After several attempts, the engine gradually approaches its operating temperature, while the control unit (ECU) cools down relatively quickly.

If that's the case, it would rather be for a definite. STG speaking, especially if it doesn't respond immediately.

Previously, it was the case that he kept waking up.
I have tried it 3-4 times in a row.

However, the waiting time after the engine stops is irrelevant. Whether it's an hour, 10 minutes, or immediately after the stop. He still needs to "orgel" this 4-5 times before he eventually comes back.

After that, it also starts up cleanly every time. Until the next stop.
Then he needs the eggs.

I will reconnect the cable to the PDE tonight and see what the pre-feeding pump is actually doing. Not that you'll lose your enthusiasm and simply refuse to work.

If communication with the control center is no longer functioning in the event of an error, then on the PD side, and at the pre-filtration pump, you don't need to look any further.

I would rather look for a source of power. If everything is clean, then the STG is most likely the best option for me.

Greetings
Guste

Has the relay for MSTG power supply (located in the engine compartment near the battery, close to the fuse box) been checked? Unfortunately, I don't know which number this model has. In older models, the 109 relay was often the cause of the problem!

Quote:

Has the relay for the MSTG power supply (located in the engine compartment near the battery, close to the fuse box) been checked? Unfortunately, I don't know which number this model has. In older models, the 109 relay was often the cause of the problem!

If the control unit is no longer able to save a fault entry, then the power supply is the most likely cause.

Does the engine light briefly illuminate when you try to start the engine again immediately after it has failed, and also when you try to access it via VCDS?

Hello
Thank you very much for the answers.
I replaced Relay 109. I also thankfully still have one of these lying around.
What is the 109 relay from the Sharan, is it well hidden in the footwell or does the Sharan have 2 of them?

However, I haven't been able to check whether the power actually arrives at the individual connectors on the control unit so far. Is there actually an overview of the control unit where the required voltage for each pin is specified?

Unfortunately, I cannot tell you whether the indicator light flashes briefly.
I didn't pay attention.
I'll watch it tonight.

I also got a very cheap control unit. It comes from a Sharan and was installed in 2014, so it's almost new.

Greetings
Bolzer

Hi,
A hot candidate is also the ignition/starting switch.
Take a look over there:
/viewtopic.php?t=27386
Since the exchange, I've been feeling fine.
You can only reliably test it if it is completely broken. However, it can also be a little broken. That's the only option.
The problem could be explained by a contact issue in the switch.
hg
Herbert

Hello
There are new findings.
The control unit and power supply are not the issue.
The reason why he hasn't accessed the fault memory after the engine stopped is still unclear.
The engine runs up to just before the 90° Motortemperatur. Then it shuts off. Then, every 2 minutes.
At this moment, the fuel pressure is significantly dropping.
The fuel pressure reaches approximately 5.5-6 bar at 4000 RPM. Shortly before 90°C, you can observe it dropping. 4 bar, 3 bar, 2 bar, then it cuts out.
If the return line is blocked, the fuel pressure will rise to 8 bar and remain stable.
Now I'm going to remove the PD elements and take a look at them.
Maybe I'll also see something on my head.

Greetings
Bolzer

Hi
Now the PDEs are outside.
The PDE from cylinder 2 is slightly damaged.
Do you think this would be enough to significantly reduce the fuel pressure?
Greetings
Bolzer

[EDIT by DBär: Doppelpost entfernt]

Quote:

The gasket of the PDE from cylinder 2 is slightly damaged. Do you think this would be enough to significantly reduce the fuel pressure?

Now... that makes sense. What does the hole in the cylinder head look like?

Hi
The seat has been minimally modified.
Estimate approximately 0.1mm.
Best regards, Bolzer

How many kilometers has the engine done? Are these the first PD (Diesel Particulate Filter) elements? PÖL or similar experiments?

Hi
The engine has 160,000 km on it.
No experiments with PÖL, chips, or anything else. From the factory.

Further insight: PDEs are not the cause.
I sent them to Steinmetz Dieseltechnik in Estenfeld for inspection.
"You informed me that the PDEs are completely defective."
The diagnosis in the original:
"All submission amounts are too low. The GDP is at the upper limit or too high. The tax columns and housing are intact. "Repairing the PDE is not possible."
Subsequently, I took them back. They were running away anyway. Not necessarily brand new, but good enough for troubleshooting.

Reinstalled. It's starting up and running. Until it cools down again.
I've swapped the return hose for a transparent one.
Initially, the engine runs normally. No air in the return, everything is fine.
As soon as it heats up, there is suddenly a huge amount of very fine air bubbles in the return, so that it seems like pure foam, and then it also shuts down when you take your foot off the gas.

Slowly, I suspect that the cylinder head has a crack between the combustion chamber and the valves.
Has anyone else experienced this?

I would just take the head off and give it to someone to crush, if I didn't happen to see something right after taking it off.

Okay, hier ist die Übersetzung:

Then, one more question.
Is the head from the A3 ASZ with the Sharan ASZ absolutely the same?
Because I might get a headache if he falls over.

Greetings
Bolzer

Quote:

Slowly, I suspect that the cylinder head has a crack between the combustion chamber and the valves.

Possible... the combustion gases then force the fuel out of the supply in the ZK.
However, I have never encountered this case before.
Is the tank ventilation okay? Have you ever tried it with the fuel tank cap open?

Best regards, Rainer

Hi.
Yes.
I tried it right away with the fuel tank open.
Best regards, Bolzer