Injection Timing ALH: Understanding the Basics

Hello, fellow diesel enthusiasts.

My Golf IV ALH 90 hp, manufactured in 02.

Since I've only been dealing with this for a few weeks, here are my questions for the ESP experts.

I used VAGCOM and the 'Basic Settings' module (specifically, module 000) to access the TDI graph.
The measured value is well above the ideal line when the engine is warm, but still within the tolerance range.

My conclusion:

The ESP is firing early and seems to be hitting the target late. (correct?)

During the trip, I checked the values displayed on the MWB 004 device.

In the LL system, the injection point is set to 0.4 degrees before TDC (BTC?), but is currently at 1.8 degrees before TDC. The touch probe ratio is 2.8%.
Therefore, I can assume that the injection timing cannot be adjusted very far towards a later timing, as TV 2.8 (the later timing limit is almost reached).

During operation, the actual values cannot reach the set points that are supposed to be achieved later in the process. However, the control range (injection timing adjuster) is very wide towards the earlier setting. Under full load (10-80), the TV (likely referring to a temperature or pressure value) is likely around 95, possibly with occasional peaks.

Are my conclusions correct?

For example, if the target line is adjusted retroactively via adaptation 004, the late values cannot be achieved anyway.
In this case, the control system doesn't adjust quite as early when operating at full load (indicated by the setpoint line). (Is this correct?)

Perhaps I am completely wrong with my claims!

Regards,

Borys.

Hello Borys,

Your conclusions are correct. If you don't mind the slightly louder idle, you don't need to adjust the injection timing.
Reason: The latest possible start of injection typically occurs at low load (LL).

A worse scenario would be a delayed injection, as this could prevent the fuel from being injected early enough, wasting power and fuel, and causing the exhaust gases to be hotter than necessary.
In addition, there's the problem that the car doesn't start easily.

Best regards, Rainer.

You were either just lucky,
or your previous owner may have specifically adjusted the ESP in order to save fuel.

Because in low-load conditions and during cold starts, late fuel injection is used for comfort and emissions reasons.
This reduces efficiency and, consequently, increases consumption.
In theory, it works, but in practice, there are different opinions and observations.

Our search function is designed to provide you with some reading material.

In my opinion, your ESP is perfectly set up, and you don't need to change anything.

Best regards, Georg.

Hello Rainer,

Thank you very much for the quick response.
I'm relieved that I finally understand the matter somewhat.
Sometimes it's difficult.
By the way, your adapter works very well.

Hello Georg,

Thank you very much as well.
The previous owner was an elderly woman. The timing belt hasn't been changed yet, it's only been done at 120,000 km. It might still be the factory setting.

Regards,

Borys.

Quote:

By the way: Your adapter works very well.

Thank you for the flowers .