rauher Leerlauf, Fehler G80+G28 | Posts 16+

Hello,

Current score:
I was able to adjust the start of the funding period, although it was a roundabout way to do so.
In my case, the ESP is easily accessible at 2 out of 3 screws, but the third one, a 6mm Allen screw, is located next to or underneath the ESP. I could only reach it with an extremely precarious extension. Unfortunately, the screw is so tight that it's now stripped.
So, I couldn't adjust the dynamic timing via the ESP (Electronic Stability Program). Instead, I rotated the camshaft wheel about 20 times until it seemed to be correct according to VCDS (a diagnostic tool).

I was quite surprised to find that it either wouldn't start at all if I adjusted the timing slightly towards "late," and when it did start, it always started too early (the values jump between 80 and 45).
The fact that the values were fluctuating like that made me suspicious.
The rough running isn't caused by a misadjusted fuel injection system, but rather...

*Drumroll*

due to a loose timing belt!
As I removed the cover, the rattling sound decreased, and I saw the timing chain "fluttering."

Okay, before I continue fiddling with the starting mechanism, I guess I need to take a quick inventory of some small parts first (tensioner, pulley, guide roller, water pump, and other small components).

Thank you for the suggestions! It was all helpful nonetheless.

Hi there,
The Northwest control system was required from the beginning. Also, please check if the bevel gear is securely attached to the crankshaft.
hg
Herbert.

benschke wrote:

Hello, Current score: I was able to adjust the start of the funding period, although it was a roundabout way to do so. The ESP is accessible at 2 out of 3 screws; one 6mm Allen screw is located next to or underneath the ESP. I could only reach it with a rather makeshift extension. Unfortunately, the screw is so tight that it's now stripped. So, I couldn't adjust the dynamic timing via the ESP (Electronic Stability Program). Instead, I rotated the camshaft wheel about 20 times until it seemed to be correct according to VCDS (a diagnostic tool). I was quite surprised to find that it either wouldn't start at all if I adjusted the timing slightly towards "late," and when it did start, it always started too early (the values jump between 80 and 45). The fact that the values were fluctuating like that made me suspicious. The rough running isn't caused by a misadjusted fuel injection system, but rather... *Drumroll* due to a loose timing belt! As I removed the cover, the rattling sound decreased, and I saw the timing chain "fluttering." Okay, before I continue fiddling with the starting mechanism, I guess I need to take a quick inventory of some small parts first (tensioner, pulley, guide roller, water pump, and other small components). Thank you for the hints! That was still all helpful.

Thank you for the feedback! But what about the polished sensor? Did I miss something that caused that?

Best regards, Rainer.

Hello Herbert,

I'm sorry, I think I misunderstood something.
Before starting the repair, I only checked the position of the camshaft at the rear end of the camshaft (I removed the camshaft sprocket and verified that the notch aligned with the edge of the housing when the engine was at top dead center, which it did quite well).
"While it was installed, I didn't notice that the timing belt was too loose; I only lifted the cover but didn't remove it. I wasn't planning on disassembling anything in the front yet. Right now, I'm doing all of this after work, on the street, and it's not as easy as it seems."
But you're right, of course. If I had checked all the steps starting from the crankshaft, I would have noticed the loose belt right at the beginning.



Hello Rainer,

Yes, I wrote something about it in my second post and attached some photos.

benschke wrote:

Thank you for your answers. I tried to press the G28 slightly to reduce the distance, but in doing so, the metal casing cracked and some oil leaked out. It probably sucked in the oil somehow. I replaced it as a precaution. Unfortunately, there is no change in the situation. The errors are still the same sporadic errors and they reappear after some time (not immediately).

Hello,

Regarding the starting process, the NHG (presumably a specific component or system) is irrelevant; therefore, proper configuration of the ESP (Electronic Stability Program) is crucial.
Unfortunately, the NHG (Neutral Hazard Generator) can sometimes exhibit intermittent malfunctions and then function normally for a long period. I experienced this with a customer vehicle, which caused unpleasant errors. After replacing the NHG, everything was fine.
However, I would first look for any chewed or damaged areas on the cables.
Also check the connectors as well. Please avoid using contact cleaner (it's too aggressive); it's better to use brake cleaner instead for cleaning connectors.

Best regards, Rainer.

Hello,
He lives again...

Over the past few days, I have replaced/updated the following:
Timing belt, front.
Front tensioner roller (including screw).
Water pump, front (including gasket).
Central screw.
Rear timing belt.

Adjusting the timing belt at the front and setting the camshaft at the front was quite simple. You just have to carefully control what you're doing. Although, you have to disassemble a lot of components at the front to access it.
Since I haven't been able to remove the hidden screw on the ESP yet, I adjusted the start of injection as best as I could using a dial indicator and the drive gear.

I checked the start of fuel injection using the default settings in VCDS with the engine at operating temperature.
The value usually fluctuates between the "early" and "optimal" lines at 90°, but every 2 seconds, a few values appear above that range, indicating they are too early.
After the test drive, the engine was slightly warmer, and the readings were generally a bit earlier, but they were still mostly within the range of the three lines (i.e., acceptable).

Okay, here's the question:
What will happen if I leave it like this?
Mehr Spritverbrauch? What else might be possible?


(As mentioned, I can't adjust it dynamically as intended because I can't loosen one of the three screws.)

Thank you for all your help!
Greetings.

You can use VCDS to display a "cloud" of fluctuating measured values, and I can show you a Screenshot of that here.
hg
Herbert.

"Cloud", see appendix.
The engine temperature was approximately 86°C after driving for about 10 kilometers.

Hi there,
Regarding the setting, I wouldn't change anything for now; it's a bit early on average, but the MSG (Motor Start Generator) will compensate for that under load.
Less desirable are the (too) significant fluctuations in the injection timing.
Since the default setting mode disables the injection start control (with ESP set to its maximum late position), the following options are possible:
- Mechanical wear of valve N108 for injection start.
- Mechanical wear in the high-pressure section of the electrostatic precipitator (ESP).
- Wiring to the valve,
- Erratic signal from sensor G28. Is the error reported earlier now resolved?
- Irregular signal from the G80 (needle lift sensor). Is the error gone here as well?
There may be other potential sources of error.
Does the engine have a VP37?
hg
Herbert.

Thank you for the assessment. I had already noticed the large variation.
The connector for valve N108 is slightly corroded. I'll try to verschandeln it.
"All the error messages from the engine are now gone and will not reappear. (The coolant temperature sensor and two actuators for the air conditioning system are still present)."
I'll take another look at the values from G28 and G80 sometime to see if anything unexpected is happening.
The fuel injection pump is a Bosch unit with the VAG part number "046 130 108 G".
Greetings.

That would be a VP37. The coolant temperature sensor should not have any influence in the basic setting mode.
Besides the ESP (Electronic Stability Program) and MSG (Multi-function Steering Wheel), only the crankshaft speed sensor, the needle lift sensor, and the fuel temperature sensor are involved. You can rule out the fuel temperature sensor based on the TDI graph; it doesn't affect injection timing in this case either.
hg
Herbert.

P.S. - The contacts should of course be cleaned as well. But you naturally have to decide when you are satisfied with the engine's performance. If it is running well now ,