AFN Engine: 3900 RPM Limit - Runaway Mode?

Hello,


I installed a 98 AFN engine in my T3. When idling, it only revs up to about 3960 rpm, and a short test drive showed very little power. There are no error codes stored. Is this the limp-home mode? How is it defined?
If so, could it be due to the well-known VTG issue?
I should probably take sick leave, but since the aggregate speed is zero, I can skip it.
Just to let you know, the engine has been sitting unused for quite some time, over a year. However, the position of the valve rocker arms is different when the engine is idling versus when it's turned off.

Regards,

Toto.

dokatoto wrote:

I installed a 98 AFN engine into my T3. At idle, it only revs up to about 3960 rpm, and a short test drive showed very little power. There are no error codes in the diagnostic system. Is this the limp-home mode? How is it defined? If so, could it be due to the well-known VTG issue?

Hi.

The symptoms, in my opinion, most likely indicate an improperly adjusted valve setting on the pump.
It's strange, because there doesn't seem to be any logic to it, but still...

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

Tell us what VAGCOM reports as the idle injection volume.

Hello,

I will check it out tomorrow morning.
What's bothering me is that, with the pedal fully depressed (100% position), the engine only revs up to exactly 3961 rpm every time.
Unfortunately, I can't do a full-throttle test drive because the bus isn't registered, and you can't register it without a technical inspection (AU), which creates a vicious cycle.
I'll still start by cleaning and checking the LMM (lambda sensor) and the entire turbocharger.

dokatoto wrote:

I'll still start by cleaning and checking the LMM (lambda sensor) and the entire turbocharger.

Hi.

I would be quite surprised if the problem was there, but you never stop learning...
In any case, during the AU test, the boost pressure briefly rises to approximately 1 bar and then drops back to around 0.3 bar when the system cuts out.

Therefore, I believe that even without turbocharging, the normal engine speed can be reached – as is the case with naturally aspirated engines.

Deleted upon request.

1. Previously, the original JX diesel fuel was used.
2. The complete AFN (artificial neural network) was implanted, including all sensors, etc.
3. Has 68,000 km (approximately 42,000 miles). The timing belt has been replaced, the pump has been adjusted to its optimal setting. Insert the key, and it starts immediately without any rattling, knocking, or smoking.
4. Yes, with original AFN filter.
5. I think it will be equipped with an open sports air filter.
6. I have nothing to say about that, but the combination of the AFN engine with the original T3 exhaust system has been installed many times without any problems, both privately and commercially by various tuners.
7. Does the original 4-pin pressure and temperature sensor have all the necessary connections?
8. I have the electronic accelerator pedal from a Golf 4.

It was the LMM (mass airflow sensor) that was the issue. It was only delivering 250mg. I disconnected the connector, and the program then showed a value of 550mg. The engine started up and ran perfectly.
I just got the replacement for the DC unit. I'll check how it performs tomorrow, and then see what the AU (presumably 'Arbeitsunfähigkeitsbescheinigung' - sick note) says.