Sporadic performance drop

Hello,

"I've been having a small problem lately, although when it occurs, it's not really small anymore."

This manifests itself as follows:
When accelerating to overtake, there's suddenly a complete loss of power, like hitting a wall. This happens in the higher RPM range, around 3500 RPM, which is why it only occurs when overtaking, as I rarely reach that RPM otherwise. What's strange is that it doesn't always happen, and when it does, it only occurs once per trip! It's like something is getting stuck and then working again after one occurrence. It only happens when the engine is warm.
The problem is that when you're driving on a country road at 100 km/h in third gear and the engine suddenly loses power, it's definitely not a good situation.

"A relay 109 should occur more often, right? It doesn't always happen. Or could it be related to a faulty AGR valve?" But then I thought, the AGR valve regulates at full load, so if it's stuck, it should cause problems sooner rather than only in the higher RPM range, right?

Sure, no problem.

PS: Approximately 180,000 km, first injectors, original EGR valve, timing belt replaced 2,000 km ago.

Hello, you meant that AGR (Abgasrückführung) regulates the exhaust gases at partial load, because at full load you can't use exhaust gas recirculation, as you need a full oxygen content.
It's possible that your AGR (Abgasrückführungssystem) isn't always closing properly, but that wouldn't typically result in such a sudden loss of power.
Sometimes, the wastegate valve can malfunction, which then results in a sudden loss of power.

@x world one

Does your computer continue to perform poorly until the next restart, or does it eventually recover on its own? 'The former, I haven't gotten around to yet (I haven't had the chance to set up logging - it's a pain).'

Best regards, WarLord.

Hi,

A typical case where the diagnosis would be easier with LDA.
That's all I can really say about it for now.

"I've installed a boost pressure gauge. However, I'm not yet sure if the boost pressure drops. The moment is quite short; as soon as I shift into fourth gear, the power returns, meaning that once the engine speed is lower again, the boost is back." It's difficult for me to look at the LDA .

Imagine this: you're in third gear, driving at around 100 km/h, and it feels like you're hitting a wall. Then I shift into fourth gear and briefly release the accelerator. After that, everything's fine until it happens again.
I've also noticed that the car smokes, even without the 10c tuning. For example, when accelerating hard from a standstill in third gear, I can clearly see "clouds" of smoke in front of the headlights of the car behind me. Or, when I'm at a traffic light and want to accelerate quickly, revving the engine to around 3500 RPM, I also see smoke coming from the exhaust.

Okay, sometimes I have problems with adjusting the boost pressure; specifically, the LDA (Lambda-controlled Diesel Air intake system) is fluctuating, sometimes only with a 10° timing advance, and sometimes even without it. But in that case, you experience a fluctuating acceleration, but not a loss of power.

Okay, then check the colored hoses that regulate the boost pressure.

Possibly 30 EUR for a new turbocharger solenoid valve 028 906 283 F.

A log would be the best way to diagnose the problem...

m

Also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also, also,

Just a side note: Not all products from 1Z are designed for use in underpressure environments.

All pressure-regulating devices are overpressure valves.

That, of course, doesn't change the fact that they should be whole .

m;

Okay, I'll check the hoses then. I think I can rule out any modifications or alterations; to my knowledge, nothing has ever been changed.
The solenoid valve should be intact, and I've checked it with a multimeter. However, it was only 3 ohms above the tolerance. Otherwise, I guess I'll just have to spend the 30 euros.

So, it happened again today.
I replaced the diesel filter and also the faulty diesel line at the same time.
After that, I'll do my usual "test run" to see if everything is working and leak-free.

And right during the test drive, the problem reappeared. As I was leaving town, I accelerated, not very strongly, because the engine was still cold. At approximately 110 km/h in 5th gear, suddenly there was no power, as if the engine had stalled. I was still gently accelerating, reaching a speed of approximately 120 km/h.

I remembered Ulf's suggestion and immediately checked the LDA. It showed almost 1 bar of boost pressure! Then the LDA dropped to around 0.6/0.7 bar and went back up to almost 1 bar. Then suddenly everything was okay, and the boost pressure was at a moderate level of around 0.5 bar, which is roughly acceptable in 5th gear at 120 km/h.

That's clearly a defect in the turbocharger pressure control system.
I noticed a small hole in a red hose connecting the magnetic valve to the turbocharger. I temporarily patched it with sealant tape from the heating sector. A new hose has already arrived, but unfortunately, the hardware store didn't have any suitable hose clamps, so I guess I'll have to use VW ones.
But this leak can't be coming from that hole, otherwise it would be happening all the time!
It only happened once during the test drive. After that, I did two pull tests and also stressed the car with a temperature of 10 degrees Celsius, but nothing, absolutely nothing. Besides the usual boost pressure fluctuations that occur with a 10c tune.

Should we just replace the solenoid valve as a precaution?

Replace the valve.

Mine sounded like a steam locomotive again today:
I installed and adjusted a fog light, so I turned the ignition on but didn't start the engine.

At first, there was nothing to hear... WEIRD...
Then I heard a faint ticking sound... it got louder, and eventually, it clicked like always!!

If I can assume that it only switches correctly when it also makes a loud ticking sound, then mine probably has a problem.

You should probably invest those 30 euros.

m;

For information:

Replacing the faulty hose on the magnetic valve - wastegate didn't solve the problem. But with the new solenoid valve, the problems of sudden pressure drops seem to have been resolved.
Anyway, the problems haven't reappeared since then.
By the way, that old solenoid valve was the very first one, manufactured in 1995 and installed in my 1996 Golf. So, it has seen approximately 180,000 kilometers (around 112,000 miles). Sometimes, it's okay if it's defective .