Defective Injection Start Valve: Troubleshooting & Repair

Hello professional thief!

Today, out of curiosity, I performed the function test for the injection start control, as described in the repair manual.
Here's how it works: You connect your laptop to the vehicle using VAG-COM, enter the basic settings mode in display group 0, and observe field 2 while the engine is idling. Initially, you'll see a value that fluctuates slightly (in my case, between 32 and 34).
By removing fuse number 43, the power supply to the injection timing control valve should be interrupted, causing the valve to move to the "closed" position. As a result, the pressure inside the ESP (Exhaust Gas Recirculation) system should increase, causing a gradual advance in the injection timing.
This is then indicated by increasing the display value to 255, which represents the maximum early offset or trigger setting.

That's the theory. In practice, unfortunately, I couldn't detect any difference at all, whether I had removed the fuse or not.
Even small gas leaks when the circuit breaker was tripped did not cause the value to increase.

I was seriously concerned about the injection start timing, but when I logged the target and actual injection start values during operation, I couldn't detect any anomalies. For example, at 4000 RPM and full load, an early timing of 15.8° was achieved. From this perspective, everything seems to be okay.

Can someone help me out? (I think I've identified the correct fuse, but I've checked it multiple times!).

Thank you for your help.

Regards,
Alex.

Deleted upon request.

@ diesel.gutav:
Thank you for the detailed help, Gustav!

Unfortunately, I have the 10-pin connector, which represents the worst-case scenario in terms of effort required.

But I'm not really too worried, as the logged values for the injection start control during operation seemed reasonable.

@all:
During this examination, I also noticed something else. When checking the dynamic injection start, I unfortunately found that my injection start is just within the tolerance range at the upper limit.
I have a feeling (I'm itching to) adjust the pump so that it operates closer to the maximum pressure setting.
But actually, the effort isn't really worth it as long as the system is working properly and the early release doesn't get affected by the early trigger, right?

It's just a feeling, but perhaps the slight loss of top speed is due to this pump setting. Under normal operation, it's rare (except maybe when overtaking) to rev the engine above 4000 RPM. However, when driving on the highway, you often keep the engine in this high RPM range for longer periods, which might be where the fuel injection timing control reaches its limits.

Has anyone in this forum gained experience in this area?

Regards,
Alex.

Hi,

Unfortunately, I don't have any experience with this topic, but I have another question.

After the ZR (presumably a component or value) was replaced, the value of '2' in group 000 is now hovering around 30.
'It was fluctuating. Before that, the value was around 50, and subjectively, the car felt like it was running at around 3000 RPM.'
lively.

Okay, here's a question.
Can I adjust the fuel injection timing via engine control unit (ECU) adaptation to achieve the same effect?
How can the previous value be reached again? By how much and in which direction would the value need to be changed?

Or is it only possible by adjusting the fuel injection pump?

After replacing the water pump, it is recommended to adjust it correctly.

You can adjust the values using adaptation, but the EDC system already does that automatically if the injection timing is incorrect.

However, if the pump is nearing its limit, the available adjustment range may not be sufficient to achieve all the desired values. In such cases, error messages such as 'injection start control limit reached' may appear.


The injector control valve can be activated using actuator analysis while the engine is running. In that case, the engine noise *must* change noticeably.

Alternatively, you can set the basic settings to channel 004, which will cause the injection control to switch between 0% and 100% every 10 seconds.

see: https://community.dieselschrauber.org/en/viewtopic.php?t=3385&highlight=

CU Gremlin.

Hello pump experts!

Quote:

The injector can be activated using actuator analysis while the engine is running. In that case, the engine noise MUST change noticeably. or you can set the basic settings to channel 004, and then the injection regulator will be set to 0% and 100% at 10-second intervals

.

I actually ran that scenario yesterday. The sound of the engine was noticeably different, just like the displayed value for the injection start.
However, what was suspicious was the fact that the displayed value always remained stuck between 7.8° and 8.1°, and did not increase further.
"In my opinion, shouldn't the value actually reach up to 15...16° when the injection timing control valve is fully actuated? Perhaps the pre-charge volume of the rotor vane pump at idle is not sufficient for further adjustment, meaning the rotor vanes cannot generate enough internal pump pressure to allow for further advance timing?"

During operation, the VAG-COM diagnostic readings often show values exceeding 15° Celsius.
Or is this a sign of a mechanical issue causing difficulty in the early adjustment range?

Thank you for your opinions and suggestions.

Regards,
Alex.

donalexo wrote:

Hello pump experts! Quote: The injector can be activated using actuator analysis while the engine is running. In that case, the engine noise MUST change noticeably. or you can set the basic settings to channel 004, then the injection regulator will be set to 0% and 100% at intervals of 10 seconds . I actually ran that scenario yesterday. The sound of the engine was noticeably different, just like the displayed value for the injection start. What was particularly strange was the fact that the displayed value always remained stuck between 7.8° and 8.1°, and did not increase further. "Wouldn't the value actually reach up to 15...16° when the injection timing control valve is fully actuated? Perhaps the pre-charge volume of the rotor vane pump at idle is not sufficient for further adjustment, meaning the rotor vanes cannot generate enough internal pump pressure to allow for further advance timing?" During operation, the VAG-COM diagnostic readings often show values exceeding 15° Celsius. Or is this a sign of a mechanical stiffness in the area of the early adjustment?

Hi Alex,

The VP 37 is based on the old distributor pumps (see technical articles on adjustment), and in those, the advance of the injection start is realized through the internal pressure, which increases with the speed, via the .
The principle is the same with the VP 37. Therefore, the full advance angle cannot be achieved at idle, just like at higher speeds.

The values you posted seem to be generally okay.
If you give it gas with the fuel injector blocked, the injection timing would almost certainly be adjusted even further to be earlier.

Hello everyone,

Here's another question about the start date of the funding.

With tuning boxes, the injection duration is extended.
to allow for a larger injection volume.
Would it not be better to turn the ESP towards the early side?
to compensate for the longer injection duration.
Or would the injection adjustment affect this mechanical aspect?
Is this about making a correction or dismissing something?

I previously submitted a post about the start of the funding period.
I read it. Unfortunately, I can't find it anymore.

Regards,
Hturbo01

@htturbo01:

Quote:

Wouldn't it be better to turn the ESP in the direction of early? to compensate for the longer injection duration. Or would the injection adjustment eliminate this mechanical issue? correcting to make it disappear?

Okay! After all, it's a control loop that is constantly trying to adjust to the target value. If you adjust the mechanical baseline so far towards "early" that the control system is constantly hitting the "late" limit, then the EDC (Electronic Diesel Control) will likely recognize this, and the result will be abnormal operation and an error message.
One approach involves a moderate mechanical adjustment to favor an earlier start, combined with an adjustment of the injection start time to also favor an earlier start, so that the static conditions are once again aligned.
However, the mechanical stress on the engine will increase significantly, as the volume of the combustion chamber increases (resulting in very high combustion pressures!!).
Sure, here's the translation:

"If at all, then only make very minor corrections!"

Regards,
Alex.

very high combustion pressures!!

One should be very cautious with such things , because excessive burn pressure can lead to the following consequences:

[img]http://www.ross-tech.net/vag-com/misc-images/TDI-kaput.JPG

-Uwe-[/img]

Hello,
Could someone please take a look at my readings? They don't really match the target values in the table (in idle, there's a 2° deviation, the duty cycle is completely off, but according to the Bosch service, everything is OK ). The engine is an AFB with TT5, and the engine noise, especially at idle, is much rougher than before.

Regards,
Dieter.

Group A: '004
RPM Ign. Timing Ign. Timing | Duty Cycle
TIME
STAMP /min ° ° %
11.88 742 -0.8 -1 73.8
12.32 742 -0.8 -1 74.2
12.76 742 -0.8 -0.8 73.4
13.2 742 -0.8 -1 73
13.64 742 -0.8 -0.8 73.4
14.08 742 -0.8 -0.8 71.8
14.52 742 -0.8 -1 74.2
14.96 742 -0.8 -0.8 73
15.4 742 -0.8 -0.8 73.4
15.84 742 -0.8 -0.8 71.4
16.28 742 -0.8 -1 73.4
16.72 742 -0.8 -0.8 73.8
17.16 742 -0.8 -1 71.8
45.76 1230 -1.6 -1.8 78.5
46.19 1253 -0.2 -1.8 74.2
46.63 1276 5.4 6.8 54.4
47.07 1346 5 5.4 56.4
47.51 1415 5 5 55.6
47.95 1508 5.6 5.4 56.4
48.39 1624 6.2 6.8 56.4
48.83 1717 5.2 6 60.4
49.27 1833 4.6 5.6 61.9
49.71 1949 4.2 4.6 62.3
50.15 2088 4.2 4.6 62.7
50.59 2181 4.4 4.6 60.8
51.03 2297 4.6 5.2 58
51.47 2436 4.8 5 56
51.91 2552 5.2 5.4 55.2
52.35 2668 5.6 5.4 52.9
52.79 2784 5.8 5.6 51.3
53.23 2900 6.2 6.6 51.3
53.67 3016 6.6 6.4 48.9
54.11 3132 7 7.2 48.9
54.55 3248 7.2 7.4 48.1
54.99 3341 7.6 7.8 46.2
55.43 3457 7.8 8.4 45.8
55.87 3550 8.2 8.4 44.6
56.26 3642 8.6 8.8 43.8
56.7 3735 9 8.4 40.6
57.14 3828 9.4 10 42.6
57.58 3944 9.8 10 42.6
58.02 4037 10 10.2 42.2
58.46 4130 10 9.8 40.2

Where is the 2-degree deviation (it's probably more like 0.2 degrees, which is fine)?
It looks good!

However, I don't think you obtained the readings at high RPM under full load, did you? Because if you had, the ignition timing advance should be around 15-16 degrees.

Regards,
Alex.

Um, I didn't mean between the target and actual values, but rather in relation to the target values of the AFB (idle 1.1-4.2°, full throttle 5-10°)... the values with 742 RPM are idle, and the rest are full throttle in 4th gear until my TT5 indicated that it needed to shift .

Regards,
Dieter.

PS: According to the list, the pulse width should be 3-70 in idle mode and 80-95 at full load -> what's going on there?

Hello,

Uwe@Ross-Tech wrote:

Quote: Very high combustion pressures!! One should be very cautious with such things , because excessive burn pressure can lead to the following consequences: ... -Uwe- What happened there? It looks more like excessive use of N

2 _O.


Best regards, Rainer.

I initially thought it might have been a water hammer or something similar, but in that case, it would have just been a connecting rod.

It doesn't seem like it was running for very long.
but that small amount seems to be achieved with A LOT of boost pressure .

1.8T?

CU Gremlin.

Gremlin wrote:

I initially thought it might be a water hammer or something similar, but in that case, it would have just been a connecting rod...

... Nonsense, that's a TDI with MEDERER connecting rods