I've installed the MSD Ignition, including an 8388 "Ready to Run" distributer, 6A ignition control, and 8207 Blaster coil. I was unable to get the tach to work, so based on the installation instructions, and the recommendation of the local reseller, I installed an 8910 tach adaptor. The tach still doesn't work. The MSD Certified Tech on their forum told me to install the 8920 adaptor because,

"Your tachometer is a current triggered (coil positive) type which will require the 8920. The 8910 cannot provide that type of signal. Any current triggered tach requires the 8920 regardless of the type of trigger source you're using. If you had a voltage triggered tach, the 8910 would be used. Early Ford and Chrysler vehicles used current trigger type tachs."

My tach triggered off the negative side of the coil with the stock mopar ignition. Anyone have experience getting a tach to work with these MSD components?

The car is a 1973 Challenger Rallye with a 340.

Rick

 

The only info I have read about is many people complained about the tach either not working at all with the MSD ignition or working but the tach was way off. The most popular solution I have seen and I did it also was to send the tach out for upgrade with new internals. I had RedlineGaugeworks upgrade mine with VDO internals. It handles most all new ignitions now. Sorry I don't have any tech info on adapters. Haven't heard anybody talk about them or their success.

Chris

 

Per the MSD tech support, I purchased the 8920 adaptor. The suggestion was to hook it up as a current triggered tach, but that didn't work. When I hooked it up as a voltage triggered tach, it worked fine. Tomorrow I'll take it out for a road test.

Rick

 

My worked perfectly. Hope you get it figured out. Electrical gremlins are the worst!

 

I would just jump the signal wire straight to the firewall connector for the tach.

 

Test dirve went fine. Car runs well. Now I have to get down to refining the timing and plug gap. I still don't know why it works as a magnetic pickup distributer, but as long as it works and it's accurate, I'm not going to complain.