AFN: High Boost Pressure - Troubleshooting

Hello!

'Yesterday, the N75 pressure sensor failed on my Golf 3 AFN. The consequence was that the engine was running in SDI mode (error code 'Intake manifold pressure control difference 565 017').'

Boost pressure: Target: approximately 1900 mbar, Actual: approximately 1100 mbar.

I bought a new one and installed it today. And it seems like the problem is already fixed.

Boost pressure: Target: approximately 1900. Actual: approximately 2500.

'However, after prolonged full-throttle driving ( >10 seconds), it switches back into limp mode (error code 'Intake manifold pressure control difference 565 017'), which I suspect is due to...'
due to excessive boost pressure.

What could be the cause?

VTG secure?


PS: I also plugged the AGR valve at the same time. It can't be related to that, right?

'EDIT by Guste: Corrected complete capitalization of the title.'

doppelteglasur wrote:

Hello! VTG secure? or?

That's a good question, have you already checked it?
Of course, it is possible.
Another possible solution is to disconnect the vacuum hose from the vacuum pump.
you put it directly on the VTG can. I think it's nice that one can achieve that.

I just tested it. It moves smoothly when suction is applied. Since I didn't have a syringe, I used my mouth. It probably isn't related to that...

doppelteglasur wrote:

Target boost pressure: approximately 1900. Actual boost pressure: approximately 2500. However, after a longer period of full acceleration (>

10 seconds), it switches back to the emergency mode.}
Well, no wonder.

The boost pressure is clearly too high. Also, 2500 is the upper limit of the measuring range, so the actual pressure might have been even higher.

If you don't want to ruin your battery, figure out what's going on before you drive again.

My guess: The hoses are twisted and improperly connected.

Please refer to the piping layout diagrams in the technical articles; it is described in detail there.

Regards,
Guste.

please provide the text you would like me to translate from German to English. i will provide only the translation, without any explanations, and i will not use consistent capitalization, even in the title.

Okay, thanks for the tip! I'll check that out right away.

I only realized about the title later ----> Sorry.




PS: @ Guste
Do you perhaps have a link to your piping plan?

doppelteglasur wrote:

Do you perhaps have a link to your piping plan?

No, I'm not going to look for it for you. Simply browsing through the articles is perfectly sufficient. There are only three pages of articles, and you'll easily find the right one just by looking at the title.

Regards,
Guste.

At that point, I had already tried searching for it myself, but I couldn't find it.
'Tax pneumatics'
According to the plan, I connected everything correctly!

Is there actually a vacuum connection between the AGR solenoid valve and the VTG solenoid valve?

I solved this problem, among other things, with the help of Gusto.


The problem was with the hose. The excessive boost pressure was caused by the fact that...
A vacuum had formed in the ATM connections between the solenoid valves.
The reason was that my predecessor had replaced the air filter box with a Twister kit.
That wouldn't be a big deal, but since the device no longer has a connection for ATM functionality, he...
He quickly removed the T-piece. Consequently, there was a vacuum in the ATM hose, which caused the VTG valve to apply full vacuum to the turbocharger.

doppelteglasur wrote:

A vacuum had formed in the ATM connections between the solenoid valves. The reason was that my predecessor had replaced the air filter box with a Twister kit. That wouldn't be a big deal, but since the device no longer has a connection for ATM functionality, he... He quickly removed the T-piece. Consequently, there is a vacuum in the ATM hose, which causes the VTG valve to control full vacuum to the turbocharger.

. . . a typical DIY project for beginners .
Following: not only excessive boost pressure, but also a constantly open EGR valve (if it is not "defective").
-> Have you ever looked inside the intake manifold?

The intake manifold doesn't appear to be excessively carboned up. Fortunately, the EGR valve seems to have been inactive for quite some time. At least, it doesn't show any activity during the actuator diagnosis.


Generally, I find it amusing that the issue wasn't noticed before (with the defective VTG pressure transducer), but only after the replacement.