My 110hp Audi TDI with the AFN engine is misfiring when idling

Okay, so my car has 300,000 kilometers on the clock. For the past six months, it's been shaking when idling. When I turn on the air conditioning, the shaking stops. If I give it a little gas, it also stops. The problem only occurs when the engine is warm. So, I took the Audi to my trusted Audi workshop and spent 1000 euros. They said it's the fuel injection pump's quantity sensor, which has too much play. Before my father spends 1600 euros on a new one, I wanted to ask you what it could be.
Best regards, Uncle Tom.

Hello,

At 300,000 km, a number of wear and tear parts are likely to need replacement. The injectors, if they haven't already been changed, are certainly at the end of their lifespan. The ESP (Electronic Stability Program) is also questionable. How long do you plan to keep the vehicle? It might be cheaper to just keep driving the car until something more serious happens.

Sincerely,
Christian

'Hey there... Since the car has many new parts and is also in excellent external condition (it's the only 1996 model here that has the original front end from the 2000 model, so it's all genuine Audi parts, not aftermarket), I have to drive this car for another 3 years... or 150,000 km... That's when I'll get a company car. The compression was tested, and it's between 24.5 and 26.7 bar, which is a very good value. The alternator has been replaced, as has the timing belt... If it were the injectors, I think it would manifest differently.'

Bosch charges 80 euros per piece for a new unit.

I think that's something you could invest in.

m;

telz wrote:

... if it were the nozzles, I think it would be expressed differently.

If you approach things this way, then any further advice will be useless.

Without checking the nozzles for their spray pattern and tightness, I would not perform any further troubleshooting based on the mileage.
Injectors are wear-and-tear parts and typically last for 150,000 to 200,000 kilometers (approximately 93,000 to 124,000 miles), depending on the quality of the fuel. You have already exceeded that interval by more than double.
Use the search function (check the nozzles...), and you'll be overwhelmed by the results. The error patterns are also rarely uniform.

And by the way, you could also try searching for "fuel pump jerking" or "fuel pump surging." This issue occurs more frequently with the VP37 (not just the 1Z model). Especially with high mileage (which you have).

Okay, so the Bosch service center nearby says it's not the injectors. You can't verschandeln injectors on a TDI anyway; they're just replaced. They suggest adding 1 liter of denatured alcohol per tank of fuel. It seems the fuel sensor is probably dirty... Well, I guess I'll go buy some denatured alcohol.

'So, the Bosch service center nearby says it's not the injectors. (But I'll check the injectors anyway). They also said that injectors on a TDI can't be cleaned; they have to be replaced. He suggested adding 1 liter of denatured alcohol per tank of fuel. Apparently, the fuel sender is probably dirty... Well, I guess I'll go buy some denatured alcohol.'

telz wrote:

So, the Bosch service around the corner says it's not the injectors. ...

Loosely inspired by Christian Morgenstern: "...because, as he concludes with sharp precision, what cannot be, must not be."

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(But I'll take care of checking the nozzles.)

It's definitely better.

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"You can't verschandeln those on a TDI either; they're just replaced," he says.

Yes, No, Yes, No... it all depends on the equipment of the specific Bosch service center. Normally, however, the nozzles are replaced.

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He means adding 1 liter of denatured alcohol per tankful.

Argh..... what kind of craft store is this
"Spiritus completely destroys the already limited lubricating effect of diesel fuel and will definitely ruin your fuel pump."
He probably wants to force you to buy a new pump!

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The donor seems to be contaminated.

That is certainly possible, and also probable.

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... well, then let's go buy some spiritus...

Have fun .....


Here's a tip: Instead of using denatured alcohol, I would try using a diesel fuel system cleaner. These products are available from various manufacturers (e.g., Liqui Moly) and can be used safely even in a concentrated form (we've discussed the search function before). These cleaning solutions are naphtha-based and are completely harmless to injection equipment.

Hello,

If you're referring to strange vibrations caused by jolting, I suspect it's the motor mounts. I definitely had exactly the same symptoms.

Regards,
Thomas (A4, AFN engine, 240,000 km)

I'm having the same problem! But only when the outside temperature reaches 20 degrees Celsius!

It seems like one of my injectors is faulty. It's injecting three times the amount of fuel compared to the others.

I will know more tomorrow!

Regards,

Manuel.

AHHHH HAAAA.... For me, the outside temperature sensor is also a Rolex (expensive). The engine mounts are like new... but I also mentioned the nozzles, but Audi says the pump is broken. Of course, that's more expensive. I went to a workshop that specializes in this kind of thing. They say that the Audi people around here don't know what they're doing. So, they're going to take a look at the car.