Injection Timing AEL: No Response to Fuel Temp.

Hello TDI community,
I drive an Audi A6 2.5 TDI with engine code AEL.

Okay, here's my observation: When adjusting the injection timing using VAG-COM, I noticed that the injection timing doesn't change in relation to the fuel temperature, meaning it doesn't follow the line in the TDI timing checker, but remains constant and shifts along the x-axis. At first, I thought I might not have observed it correctly, so I tried again.
I disconnected the fuel temperature sensor's wiring and connected a potentiometer to simulate a temperature change, and sure enough, I was right. There's no reaction to the temperature changes.

My question is: Am I making a logical error here? In the default setting, the valve for the ice crystal formation starts is constantly activated and set to 'late,' so that nothing can change it anymore?

'In any case, I'm getting the same value for the injection timing during cold starts and at operating temperature in the basic setting, which can't be right.'

Hello,

Quote:

My question is: Am I making a logical error?

Okay. The fuel injection pump and the fuel injection timing adjuster don't care what you do with the potentiometer; they will always be controlled in the same way (always at the maximum late timing).
However, the actual behavior with warm/cold fuel is different. If you want to simulate this, you need to compare the values once with a cold fuel injector and engine, and once with a warm fuel injector and engine.

Best regards, Rainer.

Okay, but then, when dynamically adjusting the pump, I wouldn't need a curve to reference, but rather a fixed value, because the control system only starts working after the initial setting is reached.

I've already taken measurements with both a cold and a warm engine, which is why I tried a simulation. However, the EDC (Electronic Diesel Control) only receives values from connected sensors, so it can't distinguish between a simulation and a real-world reading. I'm always getting the same value, regardless of the temperature, and that value is the one I've set. That's why I'm asking this question.

Quote:

However, the EDC only receives values from connected sources, so it cannot distinguish between a simulation and reality.

Basically, she doesn't even need to do that in the default settings.

Best regards, Rainer.

How come I don't get it?

When I go into the basic setting during a cold start, the displayed value is '38', which is already almost outside the acceptable range!

When I test it again after 15km, it's still showing '38', which can't be right!

And what's the same about that now?

Pictures of before and after getting the beer...

Best regards, Rainer.

Here it is right away, or what?

Just to be clear: around 10:10 AM and 10:30 AM, and it wasn't just about beer...

Okay, I'm curious now! Good night for now, Best, Holger.

Does anyone have any more ideas? The differences between Rainer's diagrams and mine are quite clear; while the injection start time follows the curve in his diagrams, it remains constant in mine.

Is there anyone among us who has observed the same phenomenon with AAT or AEL, or who might be able to try the same experiment?

I now believe that the problem is not due to a fault in my EDC system, as a second engine control unit that is already installed does not exhibit the same behavior.

Best regards, Holger.

Hello!
I'm currently dealing with a similar problem on an AAT. So, my first question is: What is your injector control valve doing? What is its duty cycle when cold/warm, in percentage? 0-40% would be okay... Or is it even moving at all? You should test it using actuator diagnostics.
Otherwise... what's the initial registration date of the vehicle? I believe there was a change in the procedure starting in 1996 for AAT/AEL systems. With the older system, the basic adjustment is done at idle, while with the newer system, the engine speed is raised to 1200 rpm during the basic adjustment via the MSG. Maybe it's just that?
Best regards,
Dominique.