How Can I use GTI Tacho On My Diesel MK1 Correctly

I have a 1.6 diesel vehicle, I want to install the following gasoline mk1 tachometer on my vehicle, how can I activate the rev counter? how can i link it to work? Anyone with knowledge that can help?

Does it show correctly, will I have problems, what kind of problems will I have?

Note: My car was actually 1.1 petrol, it was converted to 1.6 diesel years ago. so now the tachometer and electrical installation on my vehicle belong to the gasoline engine.

has to do with having a "W" jack on the back of the alternator.

See the following:
https://www.4crawler.com/Diesel/CheapTricks/Tachometer/index.shtml