AHF: Optimal Spray Start Values Needed Now

Hello,

My mother's Golf 4 was recently in for a timing belt replacement, and it's been starting poorly ever since! I read an article about cold starting problems, so I thought I'd check it out.
According to the diagrams, the value (at 100 degrees) should be somewhere between 30 and 70, but it's actually around 20.
However, I'm not sure because the AHF (presumably a specific term or acronym) isn't listed in the diagrams, and I'm wondering if it might be different in that case.
I couldn't find anything related to that in my search.

Surely, someone must have something to say about that...

andre wrote:

Surely someone must have something to say about that...

Set the initial value relatively high and use VAGCOM while driving to ensure that the control system disengages from the late-engagement setting at the latest when operating at moderate load.

Then the starting problems should also be resolved, provided they are caused by the pump settings.

I didn't actually want to just start tinkering with the car without knowing if it's even necessary.

Hello,

Here's the procedure:
VAG-COM -> Engine Control Module -> Basic Settings Mode -> TDI Timing Button to start the injection timing tool.
Then you'll see what's going on.
The engine should be nice and warm, so it's a good idea to drive it for about 10km beforehand.

Best regards, Rainer.

Rainer K. wrote:

VAG-COM -> Engine Control Module -> Basic Settings Mode -> TDI Timing Button to start the injection timing tool.

Hi Rainer,

It was about finding the correct diagram for the engine.

Does VAGCOM reliably provide the correct target value based on the control unit (ECU) number, if there are multiple possibilities?


@andre:
If you don't want to unnecessarily tinker with the car, perform the diagnostic drive as described beforehand, as a check against your diagram.

If the system triggers the early detonation at full throttle or even at partial load, the pump is set too late (assuming the knock sensor is functioning correctly).

ulf wrote:

If there are different values: does VAGCOM definitely provide the correct target value based on the STG number?

Almost .

Currently, you need to select the correct engine from a drop-down menu.
I am currently working on a modified version of a plugin interface that will allow us to retrieve this information directly from the control unit.

Best regards, Rainer.

Okay, I've looked again, but I can't find the described option with the dropdown menu, and I'm also not sure how to properly check when the thing triggers on which input.
Okay, it's a bit of a hassle, but maybe someone can give me a little guidance on where to find this in VAGCom and what I should log so that someone can actually use the data (I already have a VAGCom device).

andre wrote:

Hmm, I've looked again, but I can't find the described option with the dropdown menu, and I don't know how to properly check when the thing goes to which contact. It's a bit annoying, but maybe someone could give me a little guidance on where to find this in VAGCom and what I should log so that someone can actually use the data (I already have a VAGCom device). (From the original post:) Since I read the technical article about the start of injection molding . . .

. . . you would have had to find this too.

Fachartikel wrote:

If you don't have a diagram for your engine, you can use the following method: while driving, check the injection timing ratio of the fuel injection control unit (normal mode, measurement block 4, field 4).

There should still be some reserve available, both above and below the minimum and maximum values.}

The error rates are in the range of 3% to 97%.