Engine Misfire: 1Z Won't Accelerate

My Audi 80 B4 1.9 TDi is giving me trouble. Right after starting, it revs up to a high RPM (around 25 seconds) before the engine control unit cuts it off (limp mode?). I had tuning chips installed before and wanted to go back to the 'standard' ones. Also, the magnetic valve for the boost pressure regulation is making a very loud rattling noise. What happened here? Is the engine control unit broken? I urgently need help!

Quote:

I had tuning chips installed before, and I wanted to go back to using the "normal" ones.

So, the problem only started occurring after reverting to the standard chips?
Then something probably went wrong (broke?).

Does the engine still behave normally with the tuning chips installed?

What does the error memory say?

Hello Ulf!

That's the problem, I installed those replacement chips, and then the problem started.
I've checked everything, but I haven't found anything. My notebook is currently away from me, so I can't check anything right now.
The tuning chips don't work at all. They won't even start the engine.

I'm really at my wit's end.