Golf 4 Speedometer for VW Vento

Enjoy your meal!

My friend would like to install a speedometer from a Golf 4 into his Vento diesel, which is a 1994 model with an AAZ engine. He bought the speedometer and the installation instructions on eBay.

We spent the whole day tinkering today, and everything seems to be working so far. However, in his AAZ engine, the signal for the tachometer is tapped from the alternator. If we now connect the corresponding pin of the Golf 4 speedometer to this signal, the tachometer shows 0 RPM with the engine idling. When you slightly press the accelerator, it jumps up to 5000 RPM and stays there until the engine is turned off.

Does anyone have any advice? I think it's because the AAZ engine doesn't have an ignition control unit from which the signal, as specified in the instructions, should be taken.

Hello,
The alternator's speed is significantly higher than the speed reported by the sensor in the engine (control unit)!!!
Best regards,
Günther.

Hmm, and what's the solution to this whole dilemma? Should I install a resistor? Should I reset the speedometer on eBay?

For the diesel combination instrument panels, a corresponding circuit needs to be built for this conversion, which has been the solution so far.

P.S.: Compare your instructions from the auction house with the following:

httP://theresias.com/tutorials/1h_g4t.htm

In general, the instructions I purchased matched the ones linked, but compared to yours, they appear amateurish and lack credibility.
I quickly skimmed through it, but I didn't come across the issue with the tachometer.
Do you have any ideas?

The topic (including the issue with the tachometer) is discussed in detail here:

http://www.motor-talk.de/showthread.php?threadid=88105

Okay, thank you very much for now. Let's see.