Idle Speed Smoothing: 1Z Engine - Missing Data

Hello, I have two questions.
Here's the translation:

'The first issue: When using VCDS (Vag Com) and accessing Group 13, Field 4 (Idle Speed smoothing for cylinder 4), my device shows no reading (an empty field) for my engine (1Z from 01/95). I previously thought this might be normal, but then I connected the device to a friend's 2002 Passat TDI, and it displayed readings for all 4 cylinders.'
Furthermore, no value is displayed in field 14 either.

2. Question: How is it possible for a distributor injection pump with edge control to supply each cylinder with an individual amount of fuel during idle, effectively achieving what the 'Idle Speed Smoothing' regulation does? Does anyone have experience with this? How does it actually work in detail?
Best regards, Harri.

Hello Harri!

It's perfectly normal to only get 3 display values with VP engines. The EDC uses cylinder 3 (with NBF) as a reference and only displays the relative differences of the other cylinders compared to that reference. With this type of evaluation, it's possible for cylinder 3 to always show a 0, but that's not very useful.

The 2002 Passat is likely to have a PD engine. With that type of engine, you'll get a reading for each cylinder.

The determination of the cylinder-specific idle injection quantity is realized via the quantity adjustment device of the VP37. Yes, it definitely has to be quite fast .
The control sleeve is moved axially to deliver the correct amount of fuel to each cylinder. However, this only works properly on the VP37 at idle and perhaps at slightly higher speeds. At even higher speeds, the dynamic range of the control system is no longer sufficient to selectively meter the fuel for each cylinder.

Regards,
Alex.

Okay, I was already worried that the control unit might be faulty. What does VAG Com group 14 show? Nothing appears for me there.
Best regards, Harri.

Hello Harri!

That is perfectly normal. The MWB 14 value is not specified, at least for VP engines.

...and keep experimenting happily!

Regards,
Alex.