Engine Failure at 180 km/h: Causes & Risks

Hello,

I'm having the following problem with my Seat Cordoba TDI (90 hp, no tuning, approximately 60,000 km mileage).
If I drive on the highway faster than 180 km/h, then the turbo shuts off and the power decreases drastically. If I then turn off the engine once and start it again, everything works fine again up to 180 km/h.

What could that be?

Thank you .

Hi,

Given the symptom you described, the engine control unit (ECU) is most likely entering a limp-home mode, which means that the fuel injection amount is being reduced to protect the engine from potential damage.
This can have several causes. In my case, it was due to excessive boost pressure that couldn't be reduced anymore because of a malfunctioning VTG (Variable Turbine Geometry) adjustment system.
Do you happen to have an OBD scanner that I can use to monitor the boost pressure? Otherwise, could you please read the error codes?
Please also provide the year of manufacture and engine code of your car.

'Please provide the text you would like me to translate from German to English.'

Okay, the year of manufacture is 1998. There's no LDA (Linear Drive Actuator) on board. The error memory is empty.

While I'm not a car mechanic, I'm also not completely helpless. Is it possible to fix the VTG adjustment issue myself?

Best regards, Kay.

If the engine enters a limp-home mode due to excessive boost pressure, there will also be an error code stored in the system's memory.
When did you read the error codes, Kay? Background: After a certain number of engine starts, errors that no longer occur are automatically cleared.
Regarding the number of engine starts: Search function, I've forgotten the value.

Best regards, Rainer.

Okay, I'll have the error memory read out again.

'Thank you anyway.'

Oh, the engine code should be AHU.

How can I make this rod functional again?

http://www.dieselschrauber.de/vtg.html

and

http://www.dieselschrauber.de/ladedruck.html

Hi Kay,

Please also check the pressure hoses of the turbocharger pressure control system -> See technical article on troubleshooting pneumatic controls!

I also once had this problem with an Audi 80 TDI: at 160 km/h, it suddenly lost power. The cause was a worn-out hose from the magnetic valve .

Best regards, Christian.

The 90hp TDIs don't have a variable geometry turbocharger (VTG), but instead use a bypass valve system. The whole thing sounds like it's experiencing excessive boost pressure, which is causing the engine to go into limp mode. It's possible that your control lever on the vacuum actuator has become misaligned with the bypass valve. Perhaps the previous owner tried to increase the boost pressure and thus the power in this way.

Thomas.

Thank you for the tip.

'Something strange happened to me today. When I got back on the highway, I thought I'd check exactly at what speed the emergency mode would activate. However, that didn't happen today. The car accelerated fully to 200 km/h and a little bit more (then the exit was already coming up). And the strange thing is that I haven't done anything to the car.'

Funny or what?

I'll keep an eye on it for now.

Here's the translation:

'Another question: What's the best way to verschandeln the mass airflow sensor (MAF), and where is the EGR valve located on the engine?'

Thank you .

The 90PS TDIs do not have a variable turbine geometry (VTG), but instead use a throttle-controlled turbocharger. In any case, it sounds like the boost pressure is too high, which causes the engine to go into limp mode. It's possible that your control valve lever has become misaligned with the throttle plate. Perhaps the previous owner tried to increase the boost pressure and thus the power in this way.

Thomas

objection:

ALH and AHF engines have the VNT17 turbocharger from Garrett. Please take this into consideration; it's a recurring issue.

Here is a picture of the type plate from my 66kW ALH loader.

CU Gremlin.