Golf IV TDI 66KW ALH WARMSTARTPROBLEME | Posts 48+

Hi,

I would explain other LMM (lambda measuring module) values by different AGR (air-gas ratio) control, as this has a significant impact on the amount of air.

Best regards,

Jan.

Does an increased fuel injection amount not also mean increased fuel consumption?

Why is this even done? Perhaps to ensure that the specified engine power remains consistent despite losses incurred by the automatic transmission?
If so, does that not imply an increase in performance for cars with manual transmissions?

Doesn't an increased fuel injection amount also mean increased fuel consumption?

Why is this even done? Perhaps to ensure that the specified engine power remains consistent despite losses incurred by the automatic transmission?
Wenn ja, bedeutet das nicht eine Mehrleistung bei Schaltwagen?

Hello,
In an automatic transmission, the torque converter 'splashes' even without a gear being engaged, and the hydraulic pump already consumes some of the engine's torque.
Best regards,
Günther.

Warm start problems with the venerable ALH engine, like with almost any other engine, usually have only one cause: not enough fuel is being delivered! The causes are extremely varied due to the complexity of the EDC15 system and potential hardware defects, and a thorough analysis of all possible causes would fill volumes. Everything else is just speculation.
Wenn kein Drehzahlanstieg bei Anlasserbetätigung messbar ist, d.h. EDC-Drehzahl ist gleich Anlasserdrehzahl, findet auch auf keinen Zylinder eine Einspritzung statt. Dies ist ein Indiz für eine fehlende Freigabe für die Einspritzung in der EDC. Die Ursachen hierfür sind begrenzt. Häufig ist es eine "verspätete" Syncronisierung von Kurbelwelle und VP, da hier Toleranzen im Geberrad (Temperatur!) die Signalqualität beeinflussen können. Der Hinweis das bei Automat Codierung der Fehler weg ist, könnte diese These stützen, da hier aufgrund unterschiedlicher Geberräder die Drehzahlsignale unterschiedlich ausgewertet werden - kann aber auch tausend andere Gründe haben da der Automat Datenstand sich deutlich von Handschalter unterscheidet. Das EDC - "Bit" stands for "success"."Synchronization," however, cannot be measured using your "tools" because it is deeply embedded within the engine control unit (ECU) software architecture. Therefore, troubleshooting with the original ECU is not feasible for VAG workshops or hobbyists, but rather an interesting task for the development departments of manufacturers who are happy to deal with such field problems – although this applies less to the very old ALH engine.I'm afraid you might have to live with your cold start problems, or just hope for the best. Sorry.

@bavarian:

Does the automatic transmission version of the ALH engine actually have a different crankshaft position sensor (crankshaft pulley) than the manual transmission version? I would be surprised by this, as it would undermine the policy of using identical parts.
"Furthermore, I don't quite understand the meaning, as I don't see any difference in the speed evaluation/resolution between the two mentioned options. But perhaps you can clarify this for us?"

Regards,
Alex.

So, this morning I tested the coding while driving.

I have found that automatic coding is absolutely unsuitable.

Reasoning:

After the realignment, everything worked perfectly. However, after driving a few meters, my ESP light started to stay on constantly. According to the control unit, the ABS/ESP control module is not receiving a response from the automatic transmission control module and is therefore reporting an error.
'The engine control unit (ECU) is showing an error: 'No signal from the powertrain bus'.'
The errors can only be deleted after I reset the encoding.


Conclusion:

Not recommended.

bafische wrote:

Wenn kein Drehzahlanstieg bei Anlasserbetätigung messbar ist, d.h. EDC-Drehzahl ist gleich Anlasserdrehzahl, findet auch auf keinen Zylinder eine Einspritzung statt. Dies ist ein Indiz für eine fehlende Freigabe für die Einspritzung in der EDC.

Hmm - how do you define the EDC engine speed and starter motor speed here?

According to my understanding, the EDC can only detect the speed at which the starter motor brings the engine up to.
With that being said, would the EDC speed always be equal to the starter motor speed, and therefore would the TDI engine never start?

Okay, I picked up my car from the mechanic. The new starter motor is actually showing impressive results. For me, the warm-start problem seems to be a thing of the past now. The engine starts better than ever before. The new starter motor definitely spins much faster than the old one. If anyone's interested, I can also post the part number and current price.

Finally, a sensible start.

Okay, so it's the starter motor after all.

It's understandable that an increase in engine speed can be helpful. I could certainly imagine a combination of different causes at play, so that the fuel injection amount might also have an influence.

I would like to clarify something: It seems to me that this is a problem specifically affecting ALH engines, or perhaps it's more pronounced in those engines?

The ALH engine has different injectors and, consequently, a higher fuel injection volume (compared to the 110 hp TDI). Perhaps this results in a less favorable combination with the ALH engine, where deviations (starter speed, fuel injection volume, injector wear, etc.) become more noticeable.

"@wutz: Did you take a look at the old starter motor, or did you happen to notice anything during the post-mortem analysis? Did the workshop perhaps also install new cables at the same time (to check for contact resistance)?"

ich hatte ja vorher hier die möglichen Ursachen alle gelesen und nach und nach abgearbeitet. Sprich Grundeinstellung überprüft, Kabel alle geprüft, Batterie geprüft usw. (siehe Seite 2 in diesem Bericht). Den Anlasser hatte ich selbst auch schon ausgebaut. Kohlebürsten sahen perfekt aus, alles sauber gemacht, gefettet und wieder eingebaut, jedoch ohne Verbesserung. Da der Anlasser im Austausch ist, habe ich den leider nicht mitbekommen. The workshop claims that the new starter motor has a higher RPM than the old one.
Currently, the car has 85,000 kilometers on the odometer, so it hasn't reached its maximum mileage yet. The engine is in its original condition, with no modifications or tuning, and it's only ever run on "Dino Diesel" fuel.

ulf wrote:

bafische wrote: Wenn kein Drehzahlanstieg bei Anlasserbetätigung messbar ist, d.h. EDC-Drehzahl ist gleich Anlasserdrehzahl, findet auch auf keinen Zylinder eine Einspritzung statt. Dies ist ein Indiz für eine fehlende Freigabe für die Einspritzung in der EDC. Hmm - how do you define the EDC engine speed and starter motor speed here? According to my understanding, the EDC can only detect the speed at which the starter motor brings the engine up to. Damit wäre immer EDC-Drehzahl = Anlasserdrehzahl, und der TDI dürfte nie anspringen?

Die EDC erhält natürlich ihre Drehzahlinformation nach einer Auswertelogik vom 60-2 Rad über den Drehzahlsensor. Die mittlere Motordrehzahl bei Anlasserbetätigung ohne Einspritzung liegt danach, je nach Ladezustand der Batterie, Stellung VTG, Zustand Luftfilter, Temperatur Öl usw.., so um die 250 U/min. Das ist hier die Motordrehzahl die sich mit diesen Parametern und dem festen Übersetzungsverhältnis zwischen Motor und Anlasser ergibt. Die könnt ihr doch bestimmt mit euren Diagnosetools über die K-Line messen. Das What do you mean by "starter motor speed"?

When you talk about a delayed warm-up behavior of 4-5 seconds, I assume that during this time the engine speed does not increase, so the motor speed remains at that average of 250 RPM. Then, the cause here is also likely to be found in the missing fuel injection authorization.

However, if speed increases occur, this can naturally be ruled out; in such cases, there are other problems that are not related to speed detection circuits or similar components.

bafische wrote:

When you talk about a delayed warm-up behavior, 4-5 seconds, I assume that during this time there is no increase in engine speed, so the engine speed remains at that average of 250 RPM. Then, the cause here can also be found in the missing fuel injection authorization.

That still seems strange to me.

If the battery and starter motor can only bring the engine up to, say, 250 rpm, and therefore nothing is initially injected, where would a sudden increase in the starter motor's power come from that could cause the EDC (Engine Control Unit) to finally start injecting fuel?

On the contrary, discharging the battery while cranking will more likely lead to a decrease in starter performance and thus engine speed, meaning that TDIs would be even less likely to start.

Or am I completely missing something here?

donalexo wrote:

@bavarian: Does the automatic transmission version of the ALH engine actually have a different crankshaft position sensor (crankshaft pulley) than the manual transmission version? I would be surprised by this, as it would undermine the policy of using identical parts. Furthermore, I don't quite understand the meaning, as I don't see any difference in the speed evaluation/resolution for either of the two mentioned options. But perhaps you can enlighten us? Regards, Alex

The flywheels (also known as "rotors"!) are almost always different due to the varying moments of inertia of the clutch or torque converter. However, that is a separate issue.
It's important to know if the flank angle or air gap between the sensor and tooth is different for the 60-2 wheel. This is often the case; I don't want to claim this specifically applies to the ALH engine, but if it does, a different calibration might be needed for the digital crankshaft position sensor (DZG) evaluation logic. This could be the reason why the warm start problem disappeared with automatic transmission coding (as mentioned in a previous post). Since the thermodynamic parameters for warm start are the same for manual and automatic transmissions, that's my suspicion.

ulf wrote:

bafische wrote: When you talk about a delayed warm-up behavior, say 4-5 seconds, I assume that during this time, there is no increase in engine speed, so the engine speed remains at that average of 250 RPM. Then, the cause here can also be found in the missing fuel injection authorization. That still seems strange to me. If the battery and starter motor can only bring the engine up to, say, 250 rpm, and therefore nothing is initially injected, where would a sudden increase in the starter motor's power come from that could cause the EDC (Engine Control Unit) to finally start injecting fuel? On the contrary, discharging the battery while cranking will more likely lead to a decrease in starter motor performance and thus engine speed, meaning that TDIs would be even less likely to start. Oder wo stehe ich hier auf dem Schlauch?

I'll give it a try.

The starter motor essentially has nothing to do with the initial engine speed during startup, and its power is not increased (nor would it come from anywhere). The fuel injection release is also not directly related to the engine speed, which depends on other parameters.
The engine's acceleration from standstill to idle speed occurs solely through energy conversion within the combustion chamber. In a diesel engine, the starter motor only provides the necessary ignition conditions in the combustion chamber, namely pressure and temperature, which are directly proportional to the engine speed during starter operation.

Just for information, the current engine speed during starter operation alone is approximately between 150 and 350 RPM above idle, meaning that the EDC threshold for fuel injection release (usually around 50 RPM) is not the issue.

Just to clarify, my initial analysis assumes that all obvious potential sources of error have already been checked and resolved, such as the starter motor, battery, compression, fuel injector spray pattern, etc., and that conventional methods have not proven helpful. If someone is trying to start a direct injection engine with insufficient starting assistance (e.g., the starter motor struggles to reach just 150 RPM), further questions on this topic are unnecessary.

bafische wrote:

The engine revving up (start) to the idle speed occurs only through energy conversion in the combustion chamber. In a diesel engine, the starter motor only provides the necessary ignition conditions in the combustion chamber.

So, do you understand "start" to mean the successful (and controlled) injection of fuel that causes the engine to run up from the starter speed to its idle speed?

Quote:

Nur zur Info, die Momentan-Motordrehzahl bei reiner Anlasserbetätigung, liegt ca. zwischen 150 und 350 U/min über ein Lastspiel, d.h. die EDC-Schwelle für Einspritzfreigabe (liegt meist bei 50 U/min) ist nicht das Problem.

Are you referring to the "uiuiuiu" sound produced by an organ, where 'u' represents approximately 150 revolutions per minute (rpm) and 'i' represents approximately 350 rpm?

And does the EDC (Engine Control Unit) typically start injecting fuel when the difference between "u" (engine speed) and "i" (target engine speed) is at least 50 rpm?

I'm sorry if I'm asking a question at a rather figurative level, but since you apparently have quite a bit of insider knowledge, I would like to translate it as closely as possible into my/our way of speaking .

ulf wrote:

bafische wrote: The engine revving up (start) to the idle speed occurs only through energy conversion in the combustion chamber. In a diesel engine, the starter motor only provides the necessary ignition conditions in the combustion chamber. So, do you understand "start" to mean the successful (and controlled) injection of fuel that allows the engine to run up from the starter speed to its idle speed? Quote: Nur zur Info, die Momentan-Motordrehzahl bei reiner Anlasserbetätigung, liegt ca. zwischen 150 und 350 U/min über ein Lastspiel, d.h. die EDC-Schwelle für Einspritzfreigabe (liegt meist bei 50 U/min) ist nicht das Problem. Are you referring to the "uiuiuiu" sound produced by an organ, where 'u' represents approximately 150 revolutions per minute (rpm) and 'i' represents approximately 350 rpm? And does the EDC (Engine Control Unit) typically start injecting fuel when the difference between "u" (engine speed in revolutions per minute) and "i" (another engine parameter, likely also in rpm) is at least 50 rpm? I'm sorry if I'm asking a question at a rather figurative level, but since you apparently have quite a bit of insider knowledge, I would like to translate it as closely as possible into my/our way of speaking.

I probably meant Risstitsch, but what matters is that the difference between "u" and "i" doesn't matter, as long as the "u" doesn't drop below 50 U/min, and the black Bosch device knows that it's currently detecting a "u".
Don't pin me down to a specific speed.
If someone is experiencing a real issue where they hear a prolonged "uiuiuiuiuiiu" sound (for 4 seconds or longer) on a warm engine, and this sound only occurs at a constant RPM, they can reach out again – hopefully, this thread will be helpful.