javila2468

1989 mustang

I installed an MSD HEI w/internal coil on my mustang and now the stock tach wont work. I connect it to the "TACH" side and it doesn't work. I tried connecting it directly to the negative side of the coil and still don't work. Tach worked just fine before the swap.

javila2468

bump!!

mjr46

is the car efi or carb converted?? when you say hei you mean them big ugly **** gm distributors??

Boss_Hotrod

Might need a tach adapter. That distributor might not produce the same signal as the stock setup did. Try calling MSD and asking them. They should know.

aode08

Yep, that's how they save money on the dizzy, because the circuitry is under load in the dizzy and cant drive the stock tachometer without overdoing itself.