CurrusDei

Hey guys. I bought my car (1971 911t) with an MSD ignition in place. It was professionally installed by a reputable Porsche shop, but the tach is acting wild. Its not dead, more like drunk...


I've been told to send off the tach for upgrades to work with the digital signal it is getting from the MSD setup, but its pricey and would take a while. If thats the answer, I'll do it, but has anyone found a better fix alternative for this? Changing a ground or something?


MSD setup:

MSD-5520




MSD-8920





MSD-8222 (installed in factory location on fan shroud, upside down)

Steve Weiner-Rennsport Systems

Where did they connect the black/purple tach wire to?

CurrusDei

Here are some pics I grabbed. There are a lot of loose ends back there... Almost looks like the tach adapter was installed then removed??

ron mcatee

Back in 1984, I did the same thing. I put a transistor ( resistor) in line between the distributor and the coil wire. Was working when I sold the car in 1986. There are probably better permanent fixes nowadays.