Kniffelaufgabe: Ursachen für unrunden PD-BUK-Kaltstart? | Posts 160+

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hiho

Does the MSTG (presumably a diagnostic system) somehow detect when a glow plug is malfunctioning? It's possible that the resistance value is within range when cold, but then something fails due to the heat generated during operation?

I'm still working on our Touran (BMN) which has a cold start problem... but I suspect it might be an issue with the diesel supply. It only starts reluctantly, even at -1°C, and takes 2-3 seconds of cranking. Maybe VCDS can show if the glow plugs are working correctly (individually for each cylinder)? The reading showed a glow time of 2.02 (are those seconds? At around -1°C and after standing for about a week).

12-12-2010, 12:58 Subject:

Please check the rotation angle. We had a case of sudden stiffness at work.

Negative twist angle (-4 to -5 degrees): This results in significant jerking during startup, but lower fuel consumption. Positive twist angle (+4 to +5 degrees): This eliminates the jerking, but increases fuel consumption.

Within the range of 0 to +2, you can find a good balance.

12-12-2010, 13:43 Subject:

Stummel wrote:

Does the MSTG somehow notice if a glow plug is no longer working properly?

It doesn't with the BUK. That's why I want to check my glow plug system and also observe the current flow during preheating.

Quote:

Check the rotation angle. We had a case of sudden hardness at work.

Negative twist angle (-4 to -5 degrees): This results in significant jerking during startup, but lower fuel consumption.
Positive twist angle (+4 to +5 degrees): This eliminates the jerking, but increases fuel consumption.

From 0 to +2, you can find a range where you have a good compromise.

This is located at 0 to -0.5.
Adjusting the ignition timing to a later point would make the engine lose power at higher RPMs...

then it's better to have "some" hesitation during cold starts in winter.

12-12-2010, 14:18 Subject:

It's certainly possible that it involves some limping. I guess it's always a compromise. Some people experience it more severely, while others don't seem to have any issues.
The issue is also independent of mileage. The car with the problem had 30,000 kilometers on it. By the way, a new head with new injectors didn't solve the problem either. The target range is plus or minus 5, but that makes a big difference for this engine.

If you set the rotation angle to plus 4, the jerking will stop.

12-12-2010, 16:35 Subject:

ulf wrote:

Stummel wrote:

Does the MSTG somehow notice if a glow plug is no longer working properly??

It doesn't with the BUK. That's why I want to check my glow plug system and also observe the current flow during preheating.

Are you sure, Ulf?
If the candles are not functioning correctly > error log > check light illuminates.

12-12-2010, 17:52 Subject:

RedR32 wrote:

If the candles are not working correctly > Error entry > Check light.

... if a separate glow plug control unit is installed, such as in BLT models or in some years of ARL production.
A system like that doesn't have that capability.

12-12-2010, 19:05 Subject:

ulf wrote:

RedR32 wrote:

If the candles are not functioning correctly > error entry > check light.

. . . if a separate glow plug control unit is installed, such as in BLT models or in some years of ARL production.
Something like that is not what the BUK system does.

Okay ULF, you definitely have glow plug monitoring, wherever those glow plugs might be located. Just because of the EU4 emissions standard.

12-12-2010, 19:29 Subject:

Hmm, I believe the glow plug control unit wasn't introduced until the newer generations, like the Golf V, Fabia II, etc. I don't think the older Ibiza had it either.

12-12-2010, 19:32 Subject:

Skoda Doc wrote:

I don't think the "Olle" Ibiza has one either.

The BLT definitely has one.

12-12-2010, 20:55 Subject:

RedR32 wrote:

So, ULF, you definitely have a glow plug monitoring system, wherever it may be located. Just because of the EU4 regulations.

Believe me, I know the BUK system pretty well.

Despite having an EU4 engine, it doesn't have the vulnerable glow plug monitoring system, nor does it have a variable geometry turbocharger (VGT) like those found in AXR or BLT engines.
Somehow, the Seatler team still managed to comply with the EU4 regulations (by a narrow margin).

12-12-2010, 22:42 Subject:

ulf wrote:

RedR32 wrote:

So ULF, you definitely have a glow plug monitoring system, wherever it may be located. Just because of the EU4 regulations.

Believe me, I know the BUK system pretty well.

Despite having an EU4 engine, it doesn't have the vulnerable glow plug monitoring system, nor does it have a variable geometry turbocharger (VGT) like those found in the AXR or BLT engines.
Somehow, the Seattle team still managed to comply with the EU4 regulations (by a narrow margin).

Well, if that's the case - unbelievable

.

12-12-2010, 22:56 Subject:

ulf wrote:

Somehow, the Seattle team still managed to comply with the EU4 regulations (by a narrow margin).

Ja, durch die geringere Schwungmasse deines Ibis gegenüber den Konzernbrüdern (Polo ... G(olf anyway).

The AXR engine was only available in the Polo and Golf models for this very reason, and not in the Passat or as an automatic transmission option.

13-12-2010, 11:25 Subject:

RedR32 wrote:

ulf wrote:

RedR32 wrote:

If the candles are not working correctly > error entry > check light.

. . . if a separate glow plug control unit is installed, such as in some BLT models or in certain years of ARL production.
Something like that is not what the BUK system does.

So ULF, you definitely have a glow plug monitoring system, wherever those glow plugs might be located.

Just because of the EU4 regulations.

I've experienced the same thing with my 2004 3BG Passat.
"That's directly controlled by the engine control unit. I wouldn't know where a glow plug would be located."

While I don't fully understand the details, it was apparently flashed because it was converted from ceramic to metal candle holders.

I've also seen a warning message about a faulty glow plug before.

14-12-2010, 17:38 Subject:

Benni wrote:

I know that from my 2004 3BG Passat as well.
"That's directly controlled by the engine control unit. I wouldn't know where a glow plug connector would be located."
. . .

With a BUK (presumably a type of engine), I can remove the glow plug fuse before a cold start without triggering an error code.
First, the act of pulling the glow plug relay is criticized -> it's hard to find a better way to demonstrate that the engine control unit (ECU) doesn't have spark plug monitoring

.

Regarding PTFE seals again:
Ich habe ungefähr vergleichbare Logs vom BUK und ASZ gefunden: ca. 40 sec BAB-Bleifuß incl. Ddiesel temperature.
Given that a faulty intermediate pressure diesel injection sealing ring apparently significantly accelerates the diesel recirculation in the common rail system (otherwise, the testing method based on the pressure drop when disconnecting the return line would not work), I believe that the diesel temperature profile should also change noticeably compared to completely intact sealing rings.
According to the log data, the ASZ-Polo *) and the BUK behave almost identically, which leads me to believe that this possibility is highly unlikely... or what do you think?

*) It doesn't exhibit any significant issues during cold starts in freezing temperatures.

(The BUK log section is slightly shorter because there were 3 MWB running in that log; in the Polo logs, there were only 2 each.)

15-12-2010, 11:23 Subject:

What is the synchronization angle for that Active Steering Zone (ASZ)?
For older models, the window is only approximately +/- 3.

Have you tried connecting a new battery?
Even with good batteries, extreme cold can cause problems.
The voltage drops briefly at the engine control unit, which delays or makes the start-up process rough.

15-12-2010, 14:04 Subject:

Skoda Doc wrote:

What is the synchronization angle for that ASZ?
For the older models, the window is only approximately ± 3

. Both are within that range: the ASZ with about -2, and the BUK with approximately 0 to -0.5.

Quote:

Have you ever tried connecting a new battery?
Even with good batteries, extreme cold can cause problems.
The voltage drops briefly at the engine control unit

, which causes a delayed or jerky start. I want to rule out this possibility for the BUK with 95% certainty: when the "stuttering" video (link on page 1) was recorded, the 72Ah battery was probably about half a year old.

Currently, I'm testing (to see if it's possible to do without approximately 6 kg of battery weight even in winter) with a 45Ah battery, and so far, the cold starts, along with the other changes, have been more positive than negative.