So I solved my jumping speedo with a new sensor and that's now perfectly stable. My tach is another story. It seems to be stable above 3500 rpm or so, but kind of wanders at lower rpms. Wondering if there's a simple fix to this or if this is just "normal" for an '82 308
I think one thing that you could try is just swapping the connectors on the two Digiplex ECUs (as only one of them generates the tach signal). If still the same tach wackiness = most likely the tach itself.
Not sure that I'd say "on its way out", but just that something in the tach signal generating circuitry of that Digiplex ECU isn't working correctly. I'd still go with the higher probability being something wrong in the tach itself, but easy enough to swap those Digiplex connectors as an initial test.
I have seen it before. I believe it is the tach itself but for sure try Steves suggestion. If that has no positive outcome call Mo-Ma Manufacturing in Albuquerque and talk to them I am reasonably sure they can fix it for you.
