Diesel Injection Timing Deviation Strategy

Hello everyone.
For most diesel engines, the injection timing deviation can be observed when the engine is idling.

If, for example, cylinder 1 shows a value of 0.17ms, does this value refer to the last combustion event (i.e., 720 degrees prior), or is the error corrected by the previously firing cylinder (cylinder 2)?

Regards,
Dominik.

In the older VEP diesel engines (1Z, AHU, AFN, etc.), one cylinder was always omitted from the display. This served as a reference point for all the other cylinders. Therefore, in a four-cylinder engine, only three readings were displayed.
It was actually quite easy to understand. However, not everyone understood it.

I can't say off the top of my head whether that's still the case with the newer models, or whether the STGs today represent an average value and all cylinders are now displayed relative to that average.

Regards,
Guste.

For the four-cylinder engines, values are displayed for all 4 cylinders. In the 2.0 CR TDI engines I'm familiar with, it shows "fuel injection deviation" in mg/stroke, while in the 1.6 CR TDI engines, it displays "injection time deviation" in µs.
Dominik has the problem that his CXXB is experiencing cold jolts, see https://community.dieselschrauber.org/en/viewtopic.php?t=30984.
According to my understanding, the idle speed control system works by providing more fuel to the weak cylinder. In this case, cylinder 1 is weak when the engine is cold. The cause is currently unclear. I would like to continue the discussion in the original thread.
hg
Herbert.

"Addition: For the 2.0 TDI's low-pressure fuel pump (LLP), we considered differences of 2mg/stroke to be borderline. In previous records, I noted injection times in idle, warm conditions of 600µs (main injection), 400µs (pilot injection 2), and 330µs (pilot injection 1), with an average of 5.4mg/stroke. If the injection time deviation for the 1.6 TDI refers to the sum of the main injection and pilot injection, then a few hundred µs would be acceptable. Of course, one would need to know the average injection volume and the logic behind the measured values."