LDA Pulsing: 10 Cent per Pulse

Hello everyone!

Now that I've finally managed to install an analog LDA in my 1Z/AHU engine, I've noticed something that I can't quite explain.

'Acceleration in 5th gear (standard power): Full throttle from approximately 1600 RPM results in a pressure overshoot of up to 1.2 bar for about 1 second, after which it quickly stabilizes at the target pressure of 0.9 bar, which is the intended behavior.'

2) Drive the high-performance vehicle on a closed racetrack for just 10 cents!

The pressure spiked to approximately 1.3 bar for about 1 second (I believe Dieselmartin may have also noted that the pressure spikes were higher), and then the LDA injector pulsed about 3 times per second, fluctuating between 0.7 and 1 bar.

What does that mean? Is the boost pressure control lagging behind and fluctuating wildly? It's definitely due to the 10 cent [piece/coin].
Or is the LDA connected incorrectly? (The tapping is located very close to the intake manifold via a T-piece, and the hose runs to the STG).

Unfortunately, I don't have a VAG Com at the moment to log that data, because my old laptop has a faulty battery.

Sure, here's the translation:

'Thank you in advance!'

Regards,

P.S. I initially connected the Lambda sensor temporarily as a test, and once during a drive, the hose detached from the Lambda sensor... However, the engine control unit (ECU) didn't go into emergency mode, even though there was full pressure at that moment, which it should have, right? Shouldn't the ECU detect that something is wrong based on the injection quantity, engine speed, and a significantly low boost pressure?
Otherwise, the loader would stop working... Is the control unit already being serviced during the Christmas holidays?

P.S. I initially connected the LDa (turbocharger pressure sensor) temporarily for testing, and once during a drive, the hose detached from the LDa... However, the engine control unit (ECU) didn't go into emergency mode, even though there was full pressure at that moment, which it should have, shouldn't it? The ECU should be able to detect that something is wrong based on the injection quantity, engine speed, and the very low boost pressure...?!
Otherwise, the loader would stop working... Is the STG already closed for the Christmas holidays?

Calculate the air intake required by the engine and then determine how much air is being released through the LDA hose.
It doesn't significantly affect the boost pressure control or the turbocharger itself.

CU Gremlin.

Calculate the air intake required by the engine and then determine the amount of air being released through the LDA hose.
It doesn't significantly affect the boost pressure control or the turbocharger itself.


But the leak was right at the pipe that goes to the STG (essentially, the pipe was disconnected from the exhaust manifold to the STG), so the STG must already be detecting it.

If it were just a 'small leak' in the charge air duct, then your answer would be correct, as it wouldn't matter much with the volume of air that passes through.

'How do you mean?'

The leak is relatively small... the pressure is spreading evenly in all directions... why should the system react with emergency shutdown, etc.? It's not yet time to react!

Hmm, I'm not sure what flaw in my reasoning I'm having right now.

So, another thought (maybe this will make it clearer what I mean).
The hose that connects to the boost pressure sensor in the engine control unit (ECU) and comes off the intake manifold is disconnected = the ECU is not receiving a measurable pressure reading!
^^ Shouldn't that be 'rewarded' with an emergency stop?

Hi,

OK, but you wrote that only the hose leading to the LDA had come off. The pressure drop in the branch leading to the MSG isn't really that high because air is coming in with far too much pressure, and that small hole could potentially change things. The MSG might see a few mBar less, but who cares?

Best regards,

Jan.

That's correct! Although, of course, it's not necessarily implied that a system failure is the inevitable consequence. In my opinion, we've just introduced an error.

'But if you have a T-connector in the line leading to the turbocharger for the LDA, and the hose that connects to the LDA is different, then it's a completely different situation (at least that's what I understood from your description). The boost pressure sensor in the engine control unit 'senses' the boost pressure, which is only slightly lower than the boost pressure with a properly connected hose.'

edit: jan was faster.

@Jan:

Okay, now I understand .
I would have thought that a leak like that in the hose leading to the control unit (STG) would cause a significantly larger pressure drop, which would make the control unit suspicious.
There's also the 'wooden hammer method' for reducing the LD (low-pressure) by poking holes in the STG (silicone tubing), and I guess I had the wrong idea about how big those holes would need to be before the pressure in the tubing noticeably drops...


Edit: @joergs: Jan was faster . Yes, the T-piece naturally connects from the hose to the control unit (STG), meaning that one side of the T-piece was open due to the detached hose at the LDA...