Audi A6 3.0 TDI ASB: Specs & Info

Hello.
After replacing a set of injectors from part number 059130277AB to part number 059130277BE on a 2006 Audi A4 B7 3.0 TDI (engine code: ASB), almost all values are identical after the zero-quantity adjustment. This is visible in measurement blocks 072-077. The new injectors are refurbished units with a test report, and are not used.
The engine has been completely rebuilt (with new pistons, cylinder head, valves, etc.). For this reason, the problem should not be related to the mechanics.
Even consulting with a certified Audi technician did not provide any clarification.
He said he's familiar with the phenomenon, but he doesn't know what causes it either.

Maybe one of you has an idea.

Thank you in advance.

What is your problem?

He's experiencing a knocking combustion noise on the right cylinder bank (cylinders 1-3). I checked the values of the injectors and found that they are almost identical to the old ones, even though these are new injectors that were coded into the engine control unit, and the engine is brand new. This is confusing, and I can't interpret these values or assess their significance. It would be a huge coincidence if the values of the old and new injectors were almost the same. I'm going to measure the return flow rates now to assess the mechanical condition, but I simply don't understand the problem described above.

What is the purpose of the idle speed control on the cylinder in question? Possible cause of the noise: A valve may not be closing properly, or there may be a leak in the gasket on the exhaust manifold.

Best regards, Rainer.

Okay, the idle speed control. I'll check that out today. It definitely should provide more meaningful information.
That's exactly why I love this forum.
I'll get back to you.

Thank you very much for now.

Okay, I've measured the idle speed control. The values seem fine to me, and the sum always adds up to almost zero, which is what it should be.
I performed three measurements and recorded the data. The first two were taken using the measurement blocks in the MSG, and the last one used the extended measurement values. The values in the blocks fluctuate significantly when read directly, making it difficult to obtain accurate readings in real-time. Checking the boxes for cylinders 1-6 under the extended measurement values provides a more stable display.

Address 01: Engine Control Module (8E0 910 401 P)

MEASUREMENT 1 (via 01-MSG / Block 13+14):
Block 013: Fuel injection control 1 (fuel injection quantity deviation).
-1.84 mg/H, Cylinder 1.
0.52 mg/H, Cylinder 2.
0.47 mg/H, Cylinder 3.
Block 014: Fuel injection control 2 (fuel injection quantity deviation).
-0.47 mg/H, Cylinder 4.
-0.66 mg/H, Cylinder 5.
1.98 mg/H, cylinder 6.

MEASUREMENT 2 (via 01-MSG / Block 13+14):
Block 013: Fuel injection control 1 (fuel injection quantity deviation).
-0.42 mg/H, Cylinder 1.
-0.71 mg/H, Cylinder 2.
0.71 mg/H, Cylinder 3.
Block 014: Fuel injection control 2 (fuel injection quantity deviation).
1.22 mg/H, Cylinder 4.
-1.22 mg/H, Cylinder 5.
0.38 mg/H, cylinder 6.

MEASUREMENT 3 (using extended readings 01-MSG / checkmarks for values for cylinders 1-6):
Block 013: Fuel injection control 1 (fuel injection quantity deviation).
-0.71 mg/H, Cylinder 1.
0.14 mg/H, Cylinder 2.
-0.19 mg/H, Cylinder 3.
Block 014: Fuel injection control 2 (fuel injection quantity deviation).
0.24 mg/H, Cylinder 4.
-0.24 mg/H, Cylinder 5.
0.75 mg/H, cylinder 6.

Next, I'm going to perform the return flow rate test, let's see what the results are.

Regarding my initial question: The new injectors (remanufactured new parts) have almost identical values compared to the old ones (original parts from the factory, approximately 140,000 km mileage). Shouldn't the new injectors, after being coded, all have values close to zero? See the table in the attachment for the values.

What about cross-boring? Could that be beneficial, perhaps by moving from one side of the cylinder head to the other?

I found this online, and while it mainly discusses idle speed values that are too far apart, the point about values that fluctuate is interesting.
'The injector codes are printed on each injector. The engine control unit (ECU) needs to know the injector code for each injector in every cylinder. This code includes information such as the injector's resistance value and its tolerance range. If, after replacing the injectors and successfully adapting them, the values of the idle speed control still show significant differences between cylinders 1-3 after an extensive test drive, but the resistance values of the injectors have changed, then the injectors are likely fine. However, if the idle speed control continues to fluctuate, injector problems will eventually arise.'

I would slowly start to stop messing around with the injectors.

If both the zero-offset calibration and the idle speed control show no abnormalities, why are you making such a big deal out of it?

Could you please record the sound and upload it here?

Best regards, Rainer.

Okay, I'll get back to you. Best regards.

Quote:

The engine has been completely rebuilt (with new pistons, cylinder head, valves, etc.).

For this reason, the cause should not be related to the mechanics. }

How many kilometers does it have on it...? Maybe it hasn't been fully broken in yet?

... and did the nailing pattern change between measurements 1 and 3?

Hello,
The new engine has approximately 5,000 km on it. In my opinion, the noise hasn't changed. However, to be certain, one would have needed to listen closely near the engine bay during the measurements, which I can certainly do. Recently, when listening near the cylinder head, I didn't notice any change; it ran for a while while stationary.

Okay then...

Quote:

Could you please make a sound recording of the noise and upload it here?

... before we continue searching.

I will get back to you with the audio recordings of the cylinder banks and the results of the return flow test.

Sounds from cylinder bank left + right:
In the recording of cylinders 1-3, a distinct, bright knocking sound can be heard, in contrast to the other bank (possibly due to slightly higher RPM). Each recording lasts 30 seconds.

Return flow rate test:
Der Test ist unauffällig, die Rücklaufmengen sind schön gleichmäßig. Füllung von ca. 20 Min. Motorlauf. Siehe Photos.
In my opinion, the test indicates that at least the needle guides appear to be tight and nothing is leaking through.

Thank you very much!

It looks good and sounds like it too. As I mentioned before, I wouldn't adjust anything else on the nozzles.

Hello,

If by 'further tests' you mean more tinkering, I'm pretty much at my wit's end. But it's certain that the injectors can't stay within these values. I think new parts shouldn't have such significant positive readings after such a short time.
While making a complaint isn't a problem since it's still under warranty, I would really like to understand why the values of the new injectors are almost exactly the same as the old ones. Especially concerning the distribution of fuel to the cylinders. It's almost like a lottery; it can't possibly be a coincidence.

P.S.: You say the noises are normal. Do you think they are the same on both sides? Maybe it's not as noticeable in the phone recording, but with your own ear, you can hear a much clearer, brighter 'ticking' sound on the left side compared to the right. The engine sounds 'normal' even when idling, I just wanted to point out the difference between the two sides.

Quote:

...the values of the new injectors are almost exactly the same as the values of the old ones.

Have you already looked for comparison values from other V6 TDIs?

What are the values now?
Shortly after the change, nothing else may be displayed except possibly all zeros, because the values are only determined under specific driving conditions and rather sporadically.
(However, I don't know the exact criteria.)