Fuel Pump for VW Passat AFN Engine

Good evening everyone,
I wanted to check my pre-lift pump in the tank today, but I'm not sure how to proceed.
I'm not sure if this is supposed to happen or not! I supplied the pump with power (via fuse 2, and you can clearly hear it running. Next, I disconnected the hose leading to the fuel injection pump and started the pump again, but no fuel came out. Now the question is: should there be fuel coming out, or is this normal?

Thank you for your help!

No AFN engine comes standard with a pre-lift pump in the tank; there's no need for one.

Sorry, I forgot!
Is it a Passat Syncro? And apparently, it has this strange tank with a pump and three fuel level sensors!

"The pump located in the tank, in my opinion, is only there to constantly refill the surge tank within the tank."
If that weren't the case, eventually one chamber would be empty while the other two would still be half full.

The VP37 draws its fuel from these dust containers (where the pump is located).

So, that means that when the pump is running, no fuel is being drawn into the suction line of the injection pump; it's only serving to equalize the pressure in the tank. I'm asking because I simply don't have the same performance as before! I want to rule out certain parts immediately because they are either new or have been checked.
- LMM
- ESP
- Turbocharger
- Filters
I'm now of the opinion that he isn't getting enough fuel.

audi200 wrote:

I would like to exclude the following parts immediately because they are new or have been inspected! - LMM - ESP - Turbocharger - Filters I've just realized that he isn't getting enough fuel!

That might be true, but it doesn't necessarily have to be. Without personal data logging and analysis, it's more like groping in the dark -> Have you read any relevant articles?

I believe I've read all the articles and then processed them one by one.
'Starting with the LMM (likely referring to a mass airflow sensor), it's new. Then, the fuel pump is okay; its values are within the normal range. Next, the injection pump was inspected and replaced; there were debris in the injector control valve (causing it to be stuck), and finally, the valve on the fuel filter has been replaced. Initially, the car could reach 210 km/h and had some slight smoke, but now it only reaches about 200 km/h without any smoke, which suggests that it might be due to insufficient fuel supply.'

Good afternoon!!!

audi200 wrote:

It initially ran at a loose 210 km/h, with some slight smoke, and now it's running just under 200 km/h without any smoke, which might suggest that it could be due to insufficient fuel!

Okay, understood.
But it could still be the mass airflow sensor (MAF) – yours wouldn't be the first one to fail as a brand new part... However, I generally think the fuel system is more likely the culprit.

I've also been considering the mass airflow sensor (MAF), but I think it might be weaker across the entire RPM range. And from everything I've read so far, you only really notice a difference with the MAF at higher RPMs.

Thank you for the previous answers!

Have you ever logged data from the mass airflow sensor (MAF)? It would be good to also log the boost pressure at the same time.

Best regards, WarLord.

Evening, Warlord.
I've done it several times before, at different intervals, after your response.
I tried it again today on the highway, once using the logging feature and once with a Screenshot. Could you perhaps send me a Screenshot or the logged files of an AFN that are working correctly?

Best regards.
Audi 200.

@audi200

'What's your problem? In the relevant measurement groups, you have setpoint and actual values. These values are also included in the log. Either you compare them directly, or you can use a product from Bill Gates called Excel to prepare them graphically for easier viewing. If the curves for the setpoint and actual values are almost identical, then you don't have a problem; otherwise, you do. You don't need logs from other people that supposedly are okay or not okay. And if you don't trust your own data, then process the logs accordingly and upload them. Then we can take a look.'

First of all, thank you to everyone who responded!
To the Warlord:
After reading your post and, as mentioned above, logging the data during my drive home (31 miles), I noticed something while reviewing the measurement blocks. Specifically, the block that compares the fuel injection amounts of each cylinder showed a significant difference: cylinder 4 (42mg) deviates greatly from cylinders 1 and 2 (85mg each). I'm not sure yet what's causing it, but I can only check further this weekend.
Sure, thanks!

To Joergs:
You're right about what you wrote; I did the same thing. That's why the ESP and the turbocharger are new – they were also defective! But after investing so much money, one becomes a bit more cautious. And on that point, I think you'll probably agree with me: comparing data or graphs can sometimes be helpful!

Best regards.
Audi 200.

audi200 wrote:

While browsing the measurement data blocks, I noticed something, specifically where the fuel injection amounts of individual cylinders are compared.

There, cylinder 4 (42mg) deviates significantly from cylinders 1 and 2 (85mg each)! I'm not sure yet what's causing it, as I can only check it out this weekend.
Then you can check the values again.

The AFN has a maximum injection volume of 40 mg.
So, differences of 42 mg } between 2 cylinders } are impossible, and 85 mg is even more so...

That's simply not possible! As I said, I only noticed it on this trip and can only check it out over the weekend. I suspect the intake manifold might be clogged, but I'll investigate and let you know what I find. Or do you have any idea how such a difference could occur? But I think that's the root of the problem!

Best regards.
Audi 200.