AAT with VP37: Key Values to Display

Hello,

"I bought an older Audi TDI with an AAT engine and automatic transmission some time ago, but unfortunately, it hasn't been running smoothly from the beginning. It has what the forums call an 'old, well-known problem': idling roughness."

After days of searching and reading in this forum and elsewhere, I finally got to work and started cleaning the VP37 and readjusting the injection timing (which was completely out of sync - it's a wonder the car even started).

"The stuttering is gone, but unfortunately, it's now difficult to accelerate, and at full throttle, the car only reaches a maximum speed of 130 km/h. The error memory is empty. I spoke with the previous owner, and he had already disassembled the VP37 injection pump, but unfortunately, he didn't mark anything or record any values."

What can I do now? Is there a list somewhere that I can use to reset the VP37 to its default settings? I'm missing all the required values. I'm especially concerned about the setpoints for the flow meter, i.e., the flow rate. According to the diagram, the start of the flow is set correctly and is at 120°C with a value of 45.

I'm at a loss.

Have you ever checked the LMM?

It's possible that the idle fuel flow is too low, especially if it's difficult to start. A value of 4-5 mg/hour is a good reading.

Hi.

Quote:

Have you ever checked the LMM?

Because I only checked the LMM (lambda sensor) using VAG diagnostic software, specifically by reading the error codes, but without any results.

Quote:

It's possible that the idle mixture is too low, especially if it's hard to start. 4-5mg/H is a good value.

In which data sheet (datasheet) can I find this value, or how do I adjust this value?

This afternoon, I tried again, adjusting the ESP unit towards the radiator, and it resulted in a noticeable improvement. Specifically, the starting behavior was perfect at -1°C, and the performance was also good. The throttle response is excellent.
Unfortunately, what happens now is that the light bulb starts blinking after about 1 minute, and the error log shows "implausible signal" from the mass flow sensor. When I turn it back towards the pump impeller, the blinking stops, but the values get worse again.

Could it be that this small lever from the MSW unit doesn't fit?

The idle speed (in the engine control module 1) needs to be adjusted very precisely (we're talking about fractions of a millimeter). I can't imagine the lever being incorrect, because in that case, the preheating indicator would be constantly flashing.

slow-moe wrote:

The idle volume (in the glow plug control module 1) must be adjusted very precisely (we are talking about fractions of a millimeter). I can't imagine that the lever is wrong, because in that case, the preheating indicator would be constantly flashing.

It's also constantly blinking, so it turns on about 30-50 seconds after the engine starts and doesn't turn off again.

If the lever were incorrectly adjusted, the preheating indicator would flash in every position of the pump head. However, it wasn't flashing before moving it, so the lever must be correct; the idle fuel quantity, however, may not be.

Hello,

Is it possible to read the amount in mg/stroke from measurement block 1? Or can this control unit not do that yet? If not, we would need to ask another experienced AAT driver what value is displayed in measurement block 0 for the injection amount (engine at operating temperature without load).

Best regards, Rainer.

Measurement blocks from a truly old AAT are likely rare because it resisted the simpler adapters. However, this one is relatively new for an AAT, probably third generation. It seems that someone experimented with an AEL on it at some point. The differences probably aren't that significant.
However, there is still a possibility that the pump or the high-pressure component is worn out, and it may no longer be possible to achieve the desired values.

Hi,

Okay, I have the AAT 3 Generation, which can read out all types of ECUs (Engine Control Units). I want to read out all the ECUs, one by one, in the new year, following the list.

http://www.dieselschrauber.de/Solldaten_5_Zylinder_VE.html

Then I'll make them available to you, maybe you'll spot some inconsistencies.

Regards,
And a happy New Year to everyone here in the forum.