83 - 9? Rabbit or Golf or Jetta

[bowmanrl]

I am putting the electronic distributor from a 85 vanagon and the Ignition Control Module from a Rabbit in my 74 super air cooled beetle. This is the same hall sensor and ICM used in the early Rabbit/Golf/Jetta. In the Rabbit section of my Chiltons manual when using a Dwell/Tach meter to check idle RPM it talks about making an adapter which is basically 2 wires connected together in a "Y" formation with a resistor on each leg. You connect the positive lead from your tach/dwell meter to were the 2 wires are joined and then it tells you to connect 1 leg to the positive side of the coil and one to ground. Otherwise it says you can damage the electronics in the ignition. It doesn't say if it is the ICM or the Hall sensor that will be damaged. My question is..... is anyone familiar with this procedure. And if I were to put a sunpro tach on my bug would I need to incorporate this "Y" resistor setup to keep my my ignition system safe? I guess the short question is has anyone ever put an aftermarket tach on a 83 or later Rabbit/Golf/Jetta and if so did you have to do anything special?

Rick

[driverlost]

All electronic tachometers work the same. They need:
A hot (positive battery)
A ground (negative battery)
& a signal. This comes from the negative coil terminal no mater mechanical points or hall effect sender.
4th wire on aftermarket tach is for illumination.

I attempted this same mod on my 65 Sundial camper with a 1641 dual port and a jetted correctly Weber Progressive carb.
I used the complete electronic ignition system from a 84 Vanagon. Distributor, Coil, and ignition box. I made it about 10 miles before the engine got so hot I had to stop to let it cool before I could make it back home.

I never went further with looking into why this happened. My guess is the advance was too much no mater where I put it to keep a decent idle. It idled and revved up nice, but the test drive showed a no good.

Anyway just wanted to share that. I'm sure someone out there has perfected this mod. I just went back to my Compufire ignition that was fine before I tried it.
_________________
Rob

May the war on Air vs Water end in my lifetime that we may all come together and enjoy the hobby.

[bowmanrl]

Yeah ignore my previous rambling....... In looking at the documentation on my tach I realized it uses the negative terminal from the coil not the positive thus eliminating the issue of concern dealing with the positive terminal of the system. Interesting feedback on your encounter with the electronic ignition. I wonder if I will encounter the same.... we will see...... I had the opposite experience with the pertronix system I bought..... it worked great for 3 months then one day on my way to a car show about a mile from the house it just quit.... not reliable enough for me. Anyone else tried converting a 1600 to the electronic hall sensor setup from a vanagon with any feedback?

Rick