the car is a 1985 s model and i have had trouble with the tach from day one. It would work on it's own terms from time to time . The car has a msd 6a installed and the problem is the wire off the secondary coil back to the cluster does not seam to do anything( i have tried primary as well). I have used a digital meter and have continuity I removed the interior just to make sure


So naturally i bought a cheep tach to test it out.

The thing is it doesn't work either. it will bump from 0-8 back to 0 like it should but still no tach. Also i tried coming straight off the msd to no luck.

Now i ask any ideas? Between this issue and the rubik's cube that is the dash i"m trying to remove i might be loosing my mind

thanks for any advice

 

https://www.summitracing.com/parts/msd-8920

"MSD magnetic pickup tach adapters maintain accurate tachometer readings. If you are using the magnetic pickup input (green and violet wires) to trigger your MSD Ignition, you will need one of these tach adapters."

I see green and violet in your picture.



Good luck!

 

so you verified the wire from the factory tach to the coil, but have you verified that the coil is firing? bad ignitor = no ignition = no tach

 

​​​​yes

 

thanks ill give it a try

 

if the ignition is working, and the wire is good, then the only other thing is the tach, i have seen a couple of flaky ones.

 

It very well my be. The only thing that leans me from that is the digital tach not working straight off the battery, but I haven't had the opportunity to do this before and know nothing about car mechanics.

 

the Rx7 just drives the tach from the coil like every other car in the world before the mid 90's.

if the coil is firing, and the wire is in the right place, the only other thing is the tach itself

 

so here is a kinda quick update. I pulled the secondary spark plug to ground to the frame of the car and cranked the ignition,no spark. So moving on i tested my coil and it checks out. I then checked my j-109 ignition module according to the fsm. it works light turns on and off however when i put a multi meter to check resistance it only works one way but im reading 26-27 mega ohms. i haven't found any threads covering that kind of resistance. I also hooked up my msd to the secondary mag-pickup and my car stars up so i can only assume that both pickups are good also the wire from coil to dizzy is good. At this point i'm probably just going to buy a second msd. any more suggestions, what im i missing. thanks for any help as always