VAG-COM: Spritzbeginn fixed, AFN engine

Hello,

After several measurements of the injection start time on my AFN, I have noticed the following:

The start of the injection process (Block0, Field2) fluctuates between values of 51 and 60 when idling.
Field 9 (Engine Temperature): 104 or 120. (2 measurements at idle).
A sequence of events based on the timing diagram from the forum cannot be established because the start of injection at idle always remains the same (or displays fluctuating values within the same range), regardless of the engine temperature.

When I'm in the Basic Settings mode, Block4 displays 8° BDTC (setpoint), while the actual value fluctuates between 7.4° and 8.6°. In Measurement mode, the display jumps between values of 1.0° and 2.0° BDTC.
The duty cycle in measurement block 4 is between 60% and 73% (idle), while in the default settings, the value fluctuates between 70% and 85%.

If I want to adjust the injection start time (Login & Adaptation, Block 3 or 5, I can't remember exactly), I can enter any value, but neither in "Test" mode nor in "Save" mode does the measured value for the injection start time change (except that the values fluctuate within a range of 1°).
All the other modules can be easily adapted.

The value for the mass of air intake is fluctuating slightly between 109 and 114 (Block0).

Is that normal?
If not, where might the defect in the system be?
Unfortunately, I don't have a "comparable vehicle," so I'm relying on your help and experience.

Regards,
macro

Hi Macro,

Is the dataset in the control unit original?
Normally, in the basic setting mode, the injection timing is set to the "latest" position, which is somewhere around 0° crank angle before or after Top Dead Center (TDC).

Best regards, Rainer.

Hello,

Well, that's a good question.
I'll look for signs to see if the control unit has been opened before.
If so, I can open it up and check the circuit board for any signs of tampering.

Is there perhaps a way to check the dataset using software, or to import the correct one (or even the entire software)?
Perhaps from a VAG workshop?

Here's something else I found in a tuning article:

Quote:

The simplest tuning approach is achieved through tuning boxes (or the functionally equivalent 10c tuning), which manipulates sensor signals, causing the engine control unit to extend the injection duration into the working cycle. "Nevertheless, the engine's computer generally doesn't detect the increased power output because it believes that the normal amount of diesel is still being injected. A characteristic feature of such operating conditions is, for example, a reduced average fuel consumption reading compared to the amount of fuel actually added."

... and I'm experiencing the same issue with my car. (There's a 10-15% discrepancy every time I refuel.)

Regards,
macro

Hi,

With the AFN, the software can only be replaced by soldering.
However, a diagnosis cannot definitively determine whether there is any tampering or modification within the program.

At the very least, the VAG part number that is read out should also be the one that is printed on the control unit.

Best regards, Rainer.

Rainer K. wrote:

However, diagnosis cannot definitively determine whether something has been tampered with in the program.

Well, if he logs the amount of fuel and the pump voltage (instead of just going through a diagnostic routine), especially in the 4th gear (since that provides more data points), I think most chip tuning modifications could be identified by comparing the logged data with the stock file.

Hello,

@Rainer: I just visited the VAG workshop. They used a touchscreen tester to read the data from the MSG (Modular Steuergerät). The identification number on the MSG matches the marking printed on the connector, and the mechanic ruled out chip tuning. He even looked in the engine compartment to check for a P-box or any other cheap tuning modifications.
The MSG appears unopened and is covered in a thick, sticky layer of dust. If you touch it firmly, you can feel this. There is still a small possibility that the MSG was modified when the car was new.

@Ulf: I'll be doing a flow test later today in 4th gear, from 1000 to 4000 RPM, and I'll log the requested values and post the log here. By the way, block 000 will also be logged, which clearly shows the injection angle.

Noch ne Frage bzgl. Software:

If I were only to modify characteristic values in an original file, it shouldn't be possible to detect those changes through the software version number displayed by VAG-COM or similar tools...
Then you could simply burn a new EEPROM and have "original software" with modified data sets (after replacing the EEPROM), or not?

Regards,
macro

Hi,

Quote:

If I were only to change characteristic values in an original file, it shouldn't be possible to see that through the version number of the software, which is accessed via VAG-COM or similar... Then you could simply burn a new EEPROM and have "original software" with modified data sets (after replacing the EEPROM), or not?

That's also the typical way it's done. However, specialists simply insert some kind of EPROM (which has been copied a hundred times beforehand) and then wonder why the car is running "weirdly." I've seen this constantly with my customers, who were sold this kind of junk.
If 'Irgendwo' is changed in the original file, that's obviously not great either. You could try changing a few bits of 'irgendwo' somewhere in a PC program and then see what happens .

What surprises me about you is the strange key mapping in the default settings.
If the injection molding machine's shut-off valve isn't closing late, and the duty cycle also doesn't indicate anything unusual, then there's definitely a problem with the software or the control unit itself.

Without further measurements and a test drive combined with measurements, a mechanic wouldn't be able to detect a chip tuning modification, even if you wrote it in size 24 font on the windshield.

Best regards, Rainer.

makrospex wrote:

@Ulf: I'll do a power test later today in 4th gear, from 1000 to 4000 RPM, and I'll log the requested blocks and post the log here. By the way, block 000 will also be logged, where you can clearly see the injection angle.

Instead of logging "000", it's better to log the actual SB-MWB value (4) -> this allows you to see the values in plain text, including the target value, and interpret them more easily.

Regarding potential tuning in your specific case, it's best to start with modules MWB 1, 4, and 8.

Hello,

@ulf: I only read your post after I returned from the logistics trip .

Here are the files:
(Group 0, 1, and 4 converted and saved as an Excel 97 workbook.)

Idle
(Here, you can clearly see the fluctuations in the values.)

Full load 1100-4000

During the full-load test, I didn't observe anything unusual in the values.
Unfortunately, I don't have any points of comparison with another AFN engine.

Regards,
macro

makrospex wrote:

During the full-load test, I didn't observe anything unusual in the values. Unfortunately, I lack comparison possibilities with another AFN engine.

Hi,

I once compared the log data from sections 1 and 4 with an AFN file from my collection: MSG 028 906 021 GH.

The fuel quantity and injection start correspond to the standard characteristic fields, but the pump voltage might indicate a 10c-style tuning (if your car and the Golf 3 have the same pump and injectors), because your pump voltages are significantly higher than what would be expected for a 021 GH characteristic field.
I was too lazy to interpolate values for quantities far outside the support points in the 5mg grid, but even the 3 red "normal?" values in the appendix illustrate my suspicion.

Hi everyone, I'm relatively new to this forum (basically a newbie), but I'm enjoying it so far.
I'm sorry to tell you that no one can check this file of the EEPROMs, at least not a VAG authorized dealership. We write the software via the PROMs (AM29F400BT), and nothing changes regarding the software number .
Even reframing the prom can be just as nice .
If you're not sure, I can also send you an .org file.
I probably still have another one.

Sincerely, herold

herold4 wrote:

If you are not sure, I can also send you an org.file. must definitely have another one

Hi,

If you have the original document from "021 CK" (which is what this is about), I would be interested. Please send it to ubeck13 aol.com, or as a zip attachment in a private message.

Thank you .

Quote:

(Here, you can clearly see the fluctuation of the values)

Well, I wouldn't call that jitter; it's more likely normal measurement inaccuracy of the EDC and normal regulatory activity.

m;

Hello,

Today, I spent 6 hours working on my Passat to ensure the following:

1.) No signs of any tampering or modifications to the ESP (Electronic Stability Program) unit, its connectors, or cables are visible.
2.) Control unit opened, no signs of tampering.
3.) Starter motor removed and tested (functioning).
4.) I also cleaned the connectors.
5.) No signs of tampering were found behind the fuse box.
6.) The vacuum system is leak-tight.

I was therefore unable to find a reasonable explanation for the increased voltage readings .

I'm going to do another 0.4, 8 Log ride tomorrow and will post the log here.

What I also found out is that the timing belt replacement was done at a Fiat workshop. There, I was told that it is generally not possible to adjust the ESP (Electronic Stability Program). I think that the ESP was not checked or adjusted after the timing belt replacement.

Now, let's go back to the secondary questions:

What could be faulty if adjusting the injection timing with VAG-COM has absolutely no effect?
Why doesn't the injection angle change with diesel temperature when the engine is idling?


Regards,
macro

makrospex wrote:

Now, let's go back to question 2: What could be defective if the injection start adjustment shows no effect at all with VAG-COM?

Nothing, because depending on the software version, adaptations for certain channels may be blocked.

Quote:

I was therefore unable to find a plausible explanation for the increased voltage values.

A real 10c tuning is certainly not behind it, because that would be reflected in the RWG voltage as a controlled regulating variable.

Since the 10c tuning only affects the RWG signal, and I couldn't detect any manipulations in the other log values, it seems like this is a chip tuning that essentially incorporates the 10c principle into the engine file.

Tell us the year your Passat was manufactured, and I'll try to figure out if it has a different fuel pump or injectors than the AFN G3, for which I've posted the RWG data.

Hello,

My Passat GT is a 35P model from the year 1996.
Model year is 1995 (which is also the year the MSG was manufactured).

I know several types of EPROM, and none of them are included in the MSG.
Or are they already available in SMD form?
Should I just try having the standard software installed by a VAG workshop?
Is that possible?


Regards,
macro