Re: @ Ulf | Posts 64+

bafische wrote:

Risstitsch, that's probably what I meant, only that the difference between "u" and "i" doesn't matter, as long as the "u" doesn't fall below 50 U/min several times, and the black box from Bosch knows that it's currently a "u". Don't pin me down to a specific speed. If someone is actually experiencing a problem where they hear a "uiuiuiuiuiiu" sound for 4 seconds or longer with a warm engine, and this "uiuiuiuiuiiu" sound only occurs at a constant RPM, they can reach out again - the purpose of this thread

should be to help.
Ah, finally we are making some progress step by step towards a solution for the troublesome starting problems .

The cars listed in my signature have started very reliably so far (both cold and warm), but I think some other people who are experiencing problems with warm starts will chime in here.

Previously, we had also considered the possibility that the minimum operating speed of the VP37 was not being reached (for example, because the vanes of the low-pressure pump were not yet being pressed tightly against the pump chamber wall due to centrifugal force).
Then one wonders why the same engine starts better when cold with a struggling starter motor than when warm at a higher RPM, or why it suddenly starts well when warm if you disconnect the connector to the water temperature sensor and simulate an arctic cold start...
Can you say something more about that?

ulf wrote:

bafische wrote: Risstitsch, that's probably what I meant, only that the difference between "u" and "i" doesn't matter, as long as the "u" doesn't fall below 50 U/min several times, and the black box from Bosch knows that it's currently a "u". Don't pin me down to a specific speed. If someone is actually experiencing a problem where they hear a "uiuiuiuiuiiu" sound for 4 seconds or longer with a warm engine, and this "uiuiuiuiuiiu" sound only occurs at a constant RPM, they can reach out again - the purpose of this thread should be to help. Ah, finally we are making some progress step by step towards a solution for the troublesome starting problems . The cars listed in my signature have started very reliably so far (both cold and warm), but I think some other people who are experiencing problems with warm starts will chime in here. Previously, we had also considered the possibility that the minimum operating speed of the VP37 was not being reached (for example, because the vanes of the low-pressure pump were not yet being pressed tightly against the pump chamber wall due to centrifugal force). Then one wonders why the same engine starts better when cold with a struggling starter motor than when warm at a higher RPM, or why it suddenly starts well when warm if you disconnect the water temperature sensor and simulate an arctic cold start... Kannst Du dazu noch etwas sagen?

I can rule out the minimum boost speed – definitely for warm starts, and possibly for cold starts as well. However, it would have to be extremely cold for that to happen, which is not common in our regions. Generating high pressure for the opening pressure of the fuel injector is not a problem for the VP37. Hot start problems due to steam bubble formation are more likely, but they occur in the high-pressure section and are also not relevant for our latitudes; it would have to be extremely hot (sweat, sweat).The design of the low-pressure section is very robust, so things usually don't go wrong with it.
However, it would be too complicated to try and find or fix the problem in the hydraulic part of the pump. Besides, there's not much a non-expert can do other than replace the entire pump.

Die zweite Frage (WTF) ist da schon relevanter. Die Menge Diesel die beim Startvorgang eingespritzt wird, wird proportional der Wasser-T. immer kleiner. Das abziehen des WTF steckers führt zu einer sog. Ersatzreaktion im MSG, d.h. die EDC rechnet mit worst case, einer simulierten WTF, d.h. - sehr sehr kalt. Da die Startmenge aber aus der simulierten WTF gerechnet wird, ist die Folge eine deutliche Erhöhung der Menge. Wenn dies der Fall ist und der Motor springt warm besser an (Müsste aber eine ordentliche Startwolke geben Okay, please provide the German text you would like me to translate into English. I will only provide the translation.l abgesehen von der Akustik und der hohen LL-DZ, hat das aber nichts mit fehlender Freigabe der Menge zu tun, sondern mit einer Mengenerhöhung die wahrscheinlich benötigt wird eine Mengendrift der Pumpe bzw. Düsen zu kompensieren. Und maThe engine does not maintain a constant speed when the starter is engaged.
However, there are other possibilities, as this experiment changes almost all parameters that influence the engine's behavior, and we only want to see the effect of the quantity being tested.

To test the following suggestion:

If the engine is warm and you're experiencing starting problems, remove the first "WTF" (presumably a sensor or component), install a second "WTF" as a dummy, then submerge the removed "WTF" in tap water heated to between 10-20°C, and then try starting the engine.
If the start is now working properly, you only need to adjust the starting dose accordingly, I would say by increasing it by 3-5mg. That's all.

bafische wrote:

: If the engine is warm and starting problems occur, then remove the first "WTF" (presumably a sensor or component), screw in a second "WTF" as a dummy, and then try to start it with the removed "WTF" submerged in tap water that's between 10-20°C warm. Ist der Start jetzt problemlos, müsst ihr nur die Startmenge entsprechend, ich sag mal um 3-5mg hochcodieren. Ready

That could be a good starting point for those who are tired of dealing with warm boot issues.

According to the sensor's characteristic curve, a water temperature of 10-20°C can also be simulated by using a 3.3 kΩ fixed resistor in the disconnected connector.

Simply insert two 3.3 kOhm resistors into the dual sensors (EDC and KI). This will cause the KI to report approximately -10°C, but hopefully the EDC won't be affected (sensor values from a Golf 3 TDI; hopefully they apply to all dual-sensor TDIs...).


By the way, my AFN (air fuel mixture) sometimes starts a little hesitantly (taking about 1 second to crank).
However, increasing the initial fuel injection volume hardly helped: the engine barely started faster, but afterwards it ran more "rough" and reached the idle speed more slowly.
More effective was adjusting the pump to the earliest permissible injection start according to the VAGCOM diagram, which resulted in a partial early injection timing of 1 to 1.5 degrees before top dead center, despite the adjustment at the late injection limit.
A correct pump setting (within the tolerance range) significantly worsened the warm start performance...

@bavarian
"On my car, the warm start used to take up to 5 seconds. The 'uiuiuiui' sound was at a consistent level and actually sounded quite fast. Now, with the new starter motor, that 'uiuiuiui' sound is significantly faster. I'll see if I can log the current starter motor speed this weekend."
The engine started immediately when the key was turned. Threatening to use the ignition key worked. When the connector for the temperature sensor was disconnected during a warm start, the car also started immediately.

@ wutz:

Since our ALH engine also suffers from this warm start problem, I would be interested in the part numbers for both the old starter motor and the new one (the one with the higher RPM).

Perhaps this summer I can finally muster the courage to give the little engine a new starter motor, so that you don't always have to crank it for 3-5 seconds with a warm engine .

I will also be conducting the WTG test.

Regards,
Alex.

Hi,

Wouldn't it be a nice "workaround" if you could simply modify the signal from the wind turbine (WTG) using a simple relay circuit (connected in parallel with the starter motor's solenoid) and a suitable resistor, so that even during a warm start, a correspondingly larger amount of power is drawn?

If the resistance is chosen in such a way that the "Russian cloud" disappears when starting or is only minimal, it might even be legally permissible.

Best regards,

Jan.

@donalexo
The part number for the new starter motor is 02A911024DX and it cost €287.10. I think the old one was 02A911023R, but I'm not entirely sure about that anymore.
So far, I haven't experienced any issues with cold or hot starts, and I'm satisfied with the product so far.
I would like to measure the idle speed sometime, but I understand that it's probably not that easy.
Regards,
Michael.

Hello!
Ein Werkstattmeister meinte gestern dazu daß das am am 'Limit' eingestellten Zahnriemen liegt. Ich war leider nicht dabei, aber er schwafelte was von 'unterer Grenze=30', und der ALH meiner Schwester hat 32. Also gerade noch im Soll, was aber schon zu Warmstartproblemen führen 'kann'. Wenn das Nachjustieren, was er aber nicht empfiehlt weil zu teuer, nichts hilft dann kanns echt am Starter liegen. Was er mit den 30 gemeint hat weiß ich nicht. Eapproximately the start of the pump's injection cycle, or something similar.

Yesterday, the Beetle was taken for a diagnosis. The Mass Air Flow sensor (MAF) was the main problem, but there's another issue. Apparently, there's overboost occurring, and according to the mechanic, this is due to a sticking Variable Turbine Geometry (VTG) adjustment mechanism. It's still working now, but it could completely fail in 3 weeks or even 3 years, causing the ALH engine to go into 'limp mode.'

Greetings.

Hello!
I also have an ALH model from 1998 with the warm-starting problems mentioned above. Recently, my starter motor failed, and since I didn't have time to replace the faulty solenoid, I quickly ordered a new starter motor online. I installed it, and the warm-starting problems are now a thing of the past.
Here are a few more details:
Starter motor No. (old): 02A911023R Bosch.
With this data, search on an online shop (e.g., Yabazzo).
Starter motor, new, now from Valeo.
Note: Power output 2 kW.
10 teeth.
Left-hand thread (for manual transmissions).
Price: €138 including all taxes and fees, excluding return of old parts.

It seems that the starter motor is often the culprit more frequently than one might think. If you've gone through all the checks listed here and haven't found a solution, then replacing the starter motor appears to be the answer.
Your starter motor was quite affordable, you can't really complain about that.

Dear fellow enthusiasts,

Of course, my 110 horsepower car also has the problem of 'starting easily when cold, but starting poorly when warm (almost embarrassingly so)' .
Pretending to have a low temperature is probably quite easy (Is the temperature sensor NTC or PTC ? ).
I have the feeling that when starting the engine warm, the starter motor barely manages to move the pistons past top dead center (TDC) due to the warm oil and good sealing of the piston rings, which results in high compression.
When the engine is cold, things work completely differently (despite my battery being 8.5 years old!).

Has anyone ever measured the starter current (cold/hot)?
Unfortunately, they didn't have the clamp meter available on Friday afternoon near the supermarket .

Copper increases its resistance by approximately 38% from, for example, -10°C to +90°C.
To decrease this value (at a constant voltage), the current drawn decreases. If the required torque now increases as well (as mentioned above, torque = current draw), it becomes clearer why the starter motor rotates more slowly.
Here, both effects come together (as you probably know, there's a saying about things going wrong).
Cold copper + low compression = excellent starting.
Warm copper + good compression = relatively poor ignition.

Out-of-the-box thinking mode: on.
A thermally decoupled starter motor should perform better.
Out of 'thinking outside the box' mode.

Simply replacing the 7-year-old battery helped improve my car's performance.

Off-topic.
A little while ago, on the highway (while driving at about 200 km/h), a ribbed belt broke on my Audi A4 (model 3B), and it also ripped off the belt for the air conditioning system.
All of that is approximately 40 kilometers from home.
The steering was stiff.
The temperature rose to almost 130 degrees, and the indicator lights started to illuminate.
And the engine barely revved up. I immediately took my foot off the accelerator and swerved to the right.
After driving home in segments of 2 kilometers (repeatedly stopping to let the engine cool down), I'm wondering if the engine might have sustained any damage. The temperature hadn't reached the red zone yet, but you still get a bad feeling when the gauge rises that high and the alarm starts beeping!

oldewurtel wrote:

Copper increases its resistance by approximately 38% from, for example, -10°C to +90°C. Um diesen Wert verringert sich (bei konstanter Spannung) der aufgenommene Strom.

That's not entirely correct!
That would only be true for a purely resistive load.
A motor is an ohmic-inductive load. Only a small portion of the supply voltage drops across the ohmic part. Consequently, the power loss will be significantly lower.

Copper increases its resistance from, for example, -10°C to +90°C by approximately 38%.
Um diesen Wert verringert sich (bei konstanter Spannung) der aufgenommene Strom.
That's not entirely correct!
That would only be true for a purely resistive load.
A motor, however, is an ohmic-inductive load. Only a small portion of the supply voltage drops across the ohmic part. Consequently, the power loss will be much lower.

Hello wolfi_b,

You are absolutely right when you say that the voltage is distributed in this way (due to counter-EMF), but purely theoretically, the voltage distribution in the winding doesn't matter. In an electric motor, when it comes to the torque produced, only the current flowing through the winding matters.

The resulting current, which depends on the magnitude of the ohmic resistance, then generates the magnetic field that produces the motor torque. This is particularly true during startup, when there is no counter-electromotive force (back EMF) yet, and therefore only the ohmic resistance is responsible for the current flowing through the winding.

Depending on the temperature of the winding, more or less current remains available for the starting torque.

But actually, I didn't want to talk in such detail about electric motors, but rather just share my experiences with the unexpectedly high copper TK (transformer coil) values that I keep encountering .