Audi 80 TDI: Jerking/Shaking in 5th Gear Above 120 mph

Hello.
Could any of you perhaps give me a tip if I'm driving at a speed of around 110-120 km/h?
'When I accelerate quickly with full throttle, it briefly behaves as if I'm releasing the gas, but then it doesn't accelerate further and gets stuck at that speed. If I release the gas or accelerate gently, this behavior repeats until around 140 km/h, after which it drops off. However, I can accelerate quickly, even with full throttle, in the lower gears without any issues.'
Würde mich über ein paar Tips von euch freuen. DThank you!

Holger.

Hi,

He who seeks shall find.
You should be able to find a lot of information about that by using the search function.

Most likely, it's a defective (and inexpensive) 'boost pressure limiting solenoid valve.'
Let's try swapping them out for now.

Okay, and if you look at the error memory of the MSTG (Motor Steuergerät), you can narrow down the cause even further...

It sounds like the diesel filter needs to be replaced. I can definitely understand the issue you're describing, as I've had a similar experience with the same type of car.

Hi Holger,

Check the hoses on the magnetic valve for boost pressure limitation (-> replace all of them). In our Audi 80, one of those hoses was worn through, causing the same symptoms. It's also a good idea to replace the valve itself at the same time.

Why doesn't anyone check the error memory? The reason for the limp-home mode is written in there... I just don't understand it. Are we back to aimlessly replacing parts again?

Rainer K. wrote:

Why doesn't anyone check the error memory? The reason for the limp mode is written in there... I just don't understand it. Are we back to aimlessly replacing parts again?

Hi Rainer,

You are of course right . However, it seems like a diagnostic system is not available. A specific hose connected to the solenoid valve is very likely the culprit, as it was not installed very intelligently in the AUDI 80 and therefore rubs during operation (this problem, for example, does not exist in the Passat). I would check that first before getting too worried.

Hi,

Rainer, logically: of course, read the error memory.
But anyone who can't figure that out without asking in the forum... well, I don't know what to say.

However, Holli's description strongly suggests that the problem lies with the solenoid valve (or hose).

Well, I'm curious to see what it is.

Hello.
I just wanted to let you know what the problem was that caused it not to start. I replaced two hoses, one of which went from a valve to the turbocharger, and since then, it's been running perfectly again.
I wanted to thank you all for the many helpful tips.

Holli.

Holli wrote:

Hello. I just wanted to let you know what the problem was that caused it not to start. I replaced two hoses, one of which went from a valve to the turbocharger, and since then it's been running perfectly again. I wanted to thank you for all the tips you gave me.

OK, thank you for the clarification!