Polo 1.4 TDI: Severe starting and idling problems

Hello,

"These problems are really driving me crazy. I'm asking all of you to help me a little, because I either can't afford to pay for everything anymore or I'm going to go insane."

Approximately 9 months ago, I bought a POLO 9N 1.4 TDI manufactured in August 2002, and I've had problems from the very beginning. The worst thing is usually when I get into the car and try to start it; it often takes two or three attempts before it starts running. During this process, the entire car shakes violently and idles at around 500 RPM. When I press the accelerator pedal, either the engine stalls, or it starts running at high RPMs.

When it's running properly, everything is great, and it can usually drive for about an hour without any problems. However, sooner or later, I approach a traffic light, and only when I come to a complete stop at the stop line, the RPM drops to around 600-700, and the whole car shakes violently. So I have to keep the RPM at 1000 by using the gas pedal.

Otherwise, everything seems to be working fine, except for the extreme shaking/jerking. When I open the hood, it feels like the engine is about to fall out.

Here's the really terrible part for me: every few days, I get in the car and try to start it, but it won't start, even after 10-20 attempts. Then I have to press the gas pedal all the way down, and sometimes I have to crank it for a minute while it idles around 600 RPM, but it still doesn't start. I keep cranking it until it finally starts.

The vehicle's diagnostic system (VAS) shows no errors in the engine.
Diesel filter replaced.
Oil and all filters have been changed.

No one knows where the problem lies.
At the repair shop, they said the engine needs to be replaced (almost as expensive as a Polo).

So, I think the engine is unlikely to be broken because when it does run, it has a lot of power and runs really well.
Sometimes it runs perfectly all day long. The start is good, the performance is good, everything is fine.

The car was a write-off due to an accident, but the engine was fine.
The mileage is extremely high for a 3-cylinder engine with 248,000 kilometers.

What I suspect:

1) Insufficient diesel fuel is arriving. (Possible causes: blocked lines, pump malfunction).
He's drawing in false air.
3) Injector nozzles clogged (due to biodiesel, heating oil, or high mileage).

I would be very grateful for a solution – please show it.
I really don't feel like getting into the car right now.

Sincerely,
Adrian W. (xadi1)

Hey.

Does anyone happen to have a solution for this problem? I'm experiencing the exact same issues with my car, and I've already replaced the mass airflow sensor (MAF) and other components.

"As I'm facing the replacement of both timing belts in the next two weeks, I would be extremely grateful for a solution, as this will ultimately determine whether I keep the car or decide to sell it."

Thank you, Olli.

Hello,

If you expect a solution, please provide more information than the first poster did. They wrote a lot, but didn't actually say anything useful.

The search function and links to common mistakes provide a lot of information on how to proceed.

Best regards, Rainer.

Okay, what can I say about my problem? I'm also having trouble finding anything relevant in the search function. Unfortunately, I can't find anything that fits my specific issue.

Here's a short explanation: My Polo has been starting very poorly lately (the battery was replaced a year ago, and I drive about 70km each way to work, five days a week).

To get started:
If it eventually starts, it shakes violently and the engine speed doesn't go above 500 RPM (even when you press the accelerator). Either it catches and runs, or it dies again, and you have to restart it. What's strange is that it usually starts more easily after that.

So far, the following items have been exchanged:
Battery, Mass Air Flow Sensor (MAF), Fuel Filter, Air Filter.

I initially thought it might be related to the fuel vent, as described in another thread, but unfortunately, that didn't solve the problem either. And what's more, once the car is running, it starts up perfectly fine again (without the aforementioned issues).

In addition to all of that, I also have very little power when the engine is cold (but it improves if I let it run for about 2 minutes). When I try to drive uphill, I really have to slip the clutch a lot so that the car doesn't stall (it doesn't respond to the throttle under load).

no errors found?
Water temperature sensor for iO?
It seems to be a cold start issue.
Best regards,

Unfortunately, no...

The donor for the temperature function isn't really working at 100% anymore, but surely that can't be due to the lack of minimum ^-1 , right?

Dirty South wrote:

No, unfortunately not... The sensor for the temperature is not really working at 100% anymore, but surely that can't be due to the lack of minimum -1 , right?

Possibly already.

I also have a Polo 1.4 TDI manufactured in 2002, and it currently has 216,000 kilometers on the odometer.
"I had the same problem a few months ago: the engine was hard to start, it idled very roughly, but everything was fine under load."
In my case, a common rail injector element was defective.
"At idle, it's injecting too little fuel, and the engine is only running on two cylinders."
You don't really notice that an element isn't injecting properly when it's running at full load.
Hello.

@mario27

My suspicion was along those lines as well, but my friend, who's a car mechanic, said that if that were the case, the emissions test (ASU) wouldn't have been okay either, and that my readings are completely normal.

Based on the mileage, it seems about right; I currently have 205,000 kilometers on mine, and it's also a 2002 model.

I think we're going to have to check that soon, because the time until the next timing belt replacement is unfortunately getting closer.

Thank you in advance for your contribution.

This diagnostic device is absolutely amazing.

It would eliminate the need for speculation about what happened to someone at some point in time.

Well, you could also just keep guessing... or simply swap everything around once. That might even lead to success. Why do people bother putting in the effort and writing about the process of troubleshooting ?

"Yes, but if the device doesn't produce any readings that correspond to the problems mentioned above, then even the best diagnostic tool won't be helpful. Moreover, I haven't experienced this problem at all since it started getting warmer!"

That's why I'm particularly interested in whether other people have experienced the same problem, or had it in the past, and if so, what caused it. This way, we can get some new ideas that we might not have thought of ourselves!

Check the sealing of the PD elements, as well as whether the valve timings are correct. Also, check if there is sufficient diesel reaching the tandem pump and that there is no foam.