I just cannot figure out this tach issue

[DynaBro]

Running an MSD 6A with tach adapter. It's wired up solid. Purple to the tach, white to grey. The tach is functional. The issue is it only works when it feels like it, which is just about 1/4 of the time. No rhyme or reason to why it does or does not work and when. I don't understand what's happening. I've gone over every connection and ground. It's all good. Could the old adapter just be shot?

One thing I believe may be incorrect is the gray wire off the tach is connected to the purple wire from the MSD and the dark blue I have no idea where it is going. I think this is backwards?

 

[RR Fan Dan]

Have you tried a different tach?

 

[DynaBro]

Have you tried a different tach?

I don't have one. Or any friends who might.

 

[RR Fan Dan]

I don't have one. Or any friends who might.

 

[WileE]

Once had an employee just like that... worked when he feels like it. Fired.

 

[DynaBro]

I am going to test the purple wire coming from the adapter with a multimeter. If that is sending the signal then I might need a new one. Or preferably someone on here who rebuilds tachs.

 

[WileE]

Get a Sun Super-Tach. Like we all did.

 

[Billccm]

Factory tach?

 

[F4R/T]

Vintage Stewart Warner or a Sun Tach

 

[RR Fan Dan]

Get a Sun Super-Tach. Like we all did.

No we all didn’t.

 

[DynaBro]

Yes factory and I aim to keep it that way. The adapter is sending a signal so it's the tach that's bad. Anyone rebuild them for an affordable price? Or is there a guide on how to open it up and troubleshoot it myself?

 

[RR Fan Dan]

What year and instrument cluster is it?

 

[DynaBro]

What year and instrument cluster is it?

70 super bee

 

[Geoff 2]

Which adapter? There is more than one type.