Polo 9N3 (1,4l TDI PD) springt schlecht an, nach Standzeit | Posts 16+

Does it have a fuel extraction pump in the tank?
If so, is it running?

[Edit]
He has a suction pump.
Control is achieved via relay J17 (slot 4), which in turn is controlled by pin 80 of the...
The MSTG is powered by a circuit breaker (upstream protection: SB61 - 15A).
Please provide the German text you would like me to translate into English. I will then give you only the translation, without any explanations.

I haven't made much progress on this topic yet.

The pump shows no signs of leakage, and I don't want to simply replace it without a clear reason.

Currently, the situation is that the Polo frequently has difficulty starting after being idle for an extended period (2 days). I have to crank the engine for a relatively long time before it starts pumping fuel again.

I'll let you know if there's anything new to report!
Thank you to everyone involved for your help!

Thank you for the feedback. Is the electric extraction pump working?

dieselschrauber wrote:

Thank you for the feedback, is the electric extraction pump running?

Yes, it's running.
Sometimes, before it struggles to start, it also makes a gurgling sound. Otherwise, you can usually hear the typical humming noise. The fuel has probably drained back into the tank in that case.

I don't want to jinx anything, but recently, in all the cases I'm aware of, the pump-nozzle units have been leaking onto the cylinder head.

Autoservice wrote:

I don't want to invoke anything, but recently, in all the cases I know of, the pump-nozzle units have been leaking into the cylinder head.

Wouldn't the engine oil also become contaminated with diesel fuel in that case?

And I just had the cylinder head refurbished (75,000 km ago), including the PD seals. Surely nothing should be leaking yet?

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Wouldn't the engine oil also become contaminated with diesel fuel in that case?

Not necessarily... only if there is a leak between the engine block and the PD (presumably referring to a specific component).

Most of the time, the leaks are small enough that only air (not liquid) passes through once the system is depressurized.

Autoservice wrote:

Not necessarily... only if there is a leak between the engine block and the PD (presumably referring to a specific component). Most of the time, the leaks are so small that only air (no liquid) passes through once the system is depressurized.

Hmm, checking that would be very time-consuming. In other words, you could really only replace the seals based on suspicion, right? I was missing the specialized tool for that...

"Put differently:" or "To put it another way:"
Is it okay if I accept that it occasionally struggles to start? Could anything get damaged by the engine "rough idling"?

Hi there!

Even if it might only alleviate the symptoms, I would install check valves on both the inlet and outlet to prevent the system from draining completely.

Cost: Under 20 euros, and some DIY required.

Best regards, Rüdi.

Hi Rüdi!

Good idea!
Do you have any other suggestions on where I can find them?

Best regards,
Volker

You can find them at a well-stocked automotive parts store, just make sure the diameter is correct!

Hello everyone!

For reference:
http://www.pierburg-service.de/ximages/pg_si_0044_de_web.pdf

Best regards from Munich!

Quote:

You can find them at well-stocked automotive parts stores; just make sure the diameter is correct!

Thank you very much!

Quote:

Hello everyone! For reference: http://www.pierburg-service.de/ximages/pg_si_0044_de_web.pdf Best regards from Munich!

Hello!

Thank you very much to you too!

Quote:

You can find them at well-stocked automotive parts stores; just make sure the diameter is correct!

Now I've taken a closer look at the valves.

According to the recommendation, a valve should be installed in the supply line, close to the tank. However, rigid plastic pipes are installed there. So, I can't easily install the valve there, right?

Hi Stolli!

As you correctly pointed out, this is merely a recommendation.
The further the check valve is located upstream of the tank in the supply line, the more potential sources of error related to the piping will be "compensated for."
On the other hand, I see a risk that by messing around with the cables and such in this already very cramped space, we might introduce even more air leaks.

Therefore, install the valve (the right way up!, of course) near the injection nozzle in the engine compartment and continue to observe. In most cases, this should resolve the problem.

Best regards from Munich!