Golf IV TDI 66KW ALH WARMSTARTPROBLEME | Posts 32+

Hi Rainer,

Rainer K. wrote:

...So, I think it's better if I delete the thread then, right?

och nöööö. Bitte nicht.

Quote:

Although there is a certain level of entertainment value, but there are other forums for that.

@Rainer

So, it would at least make sense to mark everything from '... and temperature sensor for the starter. The starter speed is thermally regulated in the TDI, because...' onwards as nonsense, or to delete it altogether.

Aber auf die Idee ist bisher absolut noch keiner gekommen also dickes Plus an Tagessuppe für die abgedrehteste Idee die mir bisher in diesem Forum begegnet ist.

Regards,
-Private

Hereby, I award the "Soup of the Day" to Tagessuppe for his outlandish idea: turning a wrench into gold .

The temperature dependence is purely physical; the copper windings heat up with the motor or during starting, and this change will be difficult to track with simple measuring devices. However, even this small change can cause a voltage drop due to the high inrush current, which in turn reduces the starting speed. That's my explanation, and my ALH starts perfectly fine (when warm) even at the current temperatures.
Andreas

Hello everyone.

To get back to the initial problem (I also had to laugh quite a bit about the issue with the regulated starter motor):

Just like Hähnlein, I have now personally experienced how the cold start performance depends on the pump setting.
The injectors with the larger nozzle size (216) and higher opening pressure in the AFN had shifted the unregulated injection start (in the basic setting mode) slightly later.
According to the diagram, the reading is between "three-quarters early" and "three-quarters late," but both values are still within the acceptable range, where, according to VAG specifications, a workshop would not typically make any adjustments.

However, the warm-up time sometimes took twice as long as usual (okay, about 2 seconds instead of 1 second is still a relatively small difference).
After adjusting the setting back to approximately three-quarters of its original value, it starts up normally again.

My tip is this: Set the pump to the tightest end of its tolerance range!

Hello everyone!
I also have an ALH engine with the well-known 'hot start problems.' In addition, I still experience occasional idling fluctuations when transitioning from under load to idle.
Today, I took the plunge and, as described in this forum previously, used VAG-COM to change the coding of the control unit from manual transmission to automatic transmission.

Result: It's running!!! No idling issues, perfect warm start.

Has anyone else had experience with this? What modifications are made to the engine? (Injection timing? Injection quantity?)

Hello everyone!
Our "new" G4-ALH also has the typical warm start problems. However, they are still within acceptable limits. After about 3-4 seconds of cranking, the ALH starts without any issues.

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Today, I took the plunge and, as described in this forum previously, used VAG-COM to recode the TCU from manual transmission to automatic transmission. Result: It's running!!! No idling issues, perfect warm start

.

It's a shame that vw66kw didn't log the meaningful measurement blocks before and after, as that might have clarified the main difference between automatic and manual transmission coding with regard to warm start behavior.

Could it be that in an automatic transmission, the pump is immediately activated without needing to reach a minimum speed, because the torque converter slows down the engine during startup?

Regards,
Alex.

Hello everyone!

I was busy this weekend and wanted to fix the cold start problem on my Audi A4 (Golf 4).
I adjusted the pump timing and set it almost to the upper tolerance limit (the maximum early setting).
Diese Maßnahme hat leider nur eine kaum merkliche Verbesserung gebracht.
Inzwischen bin ich Meister im "oberen Druckrohr aus- und einbauen". Da ich mal wieder 4-5 Versuche benötigt habe, um die Einstellung genau auf die "früh"-Linie hinzubekommen, bekommt man mächtig Übung bei solcherlei Aktionen. Für die Aktion: Druckrohr ausbauen, Pumpenrad neu justieren, Druckrohr wieder einbauen und Motordaten mittels VAG-COM prüfen habe ich max. 5 Minuten pro Durchgang benötigt. Da hat sich die Übung an meinem A3 ausgezahlt gemacht!
Occasionally, I had a setting that was so early that the timing point was no longer within the VAG timing window. With this setting, the ALH engine started immediately. Unfortunately, this setting is not suitable for normal engine operation because it's far too advanced.

I also checked the starter motor's ground connection for corrosion, but without success.

The ALH starts very sluggishly, even though all the settings are actually optimal .

Maybe I should try automatic coding sometime!

Regards,
Alex.

EDIT: I also tried increasing the cold start amount via the adaptation channel (I believe it's channel 5). Unfortunately, I couldn't achieve any change in the displayed value (I think it was 26.2 mg/H). Then, I simply reset the value back to the factory setting of 32768 and finished.
What are your values like? In my opinion, wouldn't an increase in the cold start injection amount also proportionally increase the warm start injection amount? Or am I mistaken?

donalexo wrote:

At one point, I had a setting that was so early that the timing point was no longer within the VAG timing window.

With this setting, the ALH started immediately. Unfortunately, this setting is not suitable for normal engine operation because it's far too early.
What does "viel zu früh" mean?
As long as he doesn't excessively rev the engine, I would maintain this setting, and that's good -> it results in better partial load performance and lower fuel consumption .

When starting the engine, it's my understanding that the injection timing is controlled, and therefore adjusted somewhat towards a later ignition point.
If you temporarily disable it by interrupting the injector control circuit, does the problem persist?

How does it start when warm, after being allowed to cool down?

Have you ever measured the voltage drop along the thick cables between the battery and the starter motor on both sides } (+ and ground)?

How much voltage does the battery provide when playing the organ?

Hello Ulf!

Quote:

What does "viel zu früh" mean? As long as he doesn't excessively rev the engine, I would maintain this setting, and that's good -> better partial load response and lower fuel consumption

.

If we define the tolerance range between the ideal and early lines as a 100% adjustment range, then the pump is currently operating at approximately 200%. This is quite a significant deviation, which could potentially lead to an error message and/or emergency operation.

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Beim Anlassen wird AFAIK der Spritzbeginn gesteuert, also auch etwas in Richtung spät gezogen.

The injection start is initially set to the maximum "early" position during starting because the ignition delay is at its highest when the engine is cold. However, this advance only occurs once a certain pump pressure has been built up, which can then act on the injection control valve. Therefore, the IMO injection start control system only begins functioning after the engine has started, which is why the initial setting is so important for starting behavior.

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Wie startet er denn warm beim Anrollenlassen?

Never tried it.

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Hast Du mal den Spannungsverlust entlang der dicken Kabel zwischen Batterie und Anlasser auf beiden Seiten (+ und Masse) gemessen?

No, it's difficult to do well when you're working alone.

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Wieviel Spannung liefert denn die Batterie beim Orgeln?

It is beyond my knowledge. However, I don't think it's related to the battery.

Do you have any experience with the adaptation channel for cold start injection volumes?

Regards,
Alex[/quote].

donalexo wrote:

IMO wird der Spritzbeginn beim Starten auf max. "früh" gezogen, da der Zündverzug bei kalter Maschine maximal ist. Allerdings gelingt diese Frühverstellung erst, sobald ein gewisser Pumpeninnedruck aufgeabut wurde, der auf den Spritzversteller wirken kann.

That's true. But if I remember correctly from my AFN training, the injection timing was already being adjusted slightly during the initial acceleration phase, which reduces premature ignition.

Quote:

Quote: Hast Du mal den Spannungsverlust entlang der dicken Kabel zwischen Batterie und Anlasser auf beiden Seiten (+ und Masse) gemessen? Nein, geht schlecht, wenn man alleine hantiert.

Disconnect the starter solenoid control cable and attach a temporary jumper wire (with a 6.3 mm spade connector) so that the starter motor engages when it is connected to the positive terminal (B+).
Then attach the measuring device to the thick cables and start it from under the hood .

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Hast Du Erfahrungen mit dem Adaptionskanal für die Kaltstarteinspritzmengen?

Not much.
The AFN started up slightly better after the warm-up adaptation, but it was noticeably "rougher" during the ramp-up to the low-load speed (difficult to describe precisely).

It worked best with the pump set to the early threshold and the standard starting amount.

The AFN started slightly better after warm-up and adaptation, but it was noticeably 'rougher' during the ramp-up to the low-load speed (difficult to describe precisely).


It sounds like: 2544 or, in other words, my worst-case alarm clock with 10 cylinders, each with a displacement of 1.5 liters .

My car (ALH) sometimes starts exactly like that (when it's cold). It makes a really awesome starting sound .

alex: Don't you have any decent crocodile clips? The good ones, the Hirschmann ones, don't even shake off an ALH connector .

CU Gremlin.

Hi Alex,

donalexo wrote:

If we define the tolerance range between the ideal line and the early line as a 100% adjustment range, then the pump is currently at approximately 200%. This is quite a large deviation, which could potentially lead to an error message and/or emergency operation.

Did he really nail it perfectly? I wouldn't want him to accidentally select the wrong timing setting in the VAG-COM software for a different control module (MSG), and then you end up adjusting everything based on an incorrect value...

I would just let it run with a deliberately "incorrect" setting to see if it starts up and runs properly (assuming normal operating sounds and no error messages).

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

I took my car to the service center today for its inspection (which was necessary due to the warranty). Of course, they noticed this extreme (4-5 second) cold start problem. I had already tried several solutions, but not all of them worked.
Starts perfectly in cold weather, mileage: 85,000 km.
Done: Had the battery checked.
Starter cleaned, brushes checked and lubricated.
Cable connections cleaned.
Diesel filter replaced.
Just a small air bubble in the diesel line - I think it's okay.
Removing the temperature sensor results in the engine starting warm immediately.
Error memory - empty.
verschandeln the air filter and the pre-filter screen (inlet to the air filter).

The friendly person wanted to replace the starter motor today and claims that the new starters have higher performance and also a higher RPM. Has anyone heard of this before? Is this actually true, or is it just a sales argument?

I don't know when starters are considered "new," but the one in my car (see signature) is from a Passat TDI made in the early 2000s. They looked identical on the outside, and I just needed one at the time... which would suggest that there hasn't been much development in starter motors over the last 15 years.

Hello everyone,

Since my ALH A3 also has these warm start problems, I tested the control unit coding by setting it to automatic mode.
Difference:
The injection amount increases from approximately 5 mg/hour to over 9.1 - 9.6 mg/hour.
The airflow meter is displaying a value of 355 instead of the expected 255.
Some other values have also changed. If anyone wants to know the exact details, I can take a closer look again.

I doubt that the mass airflow sensor is suddenly letting more air through. Does that mean that the automatic coding is interpreting the delivered analog values differently?

And what are the consequences if I leave it set to automatic encoding?

Sure, no problem! Just provide the text you want me to translate.

Regards,
Chris.