That's a known issue with the Auto Spiders. TSB 40.93.04 has a fix which involves running a dedicated 12V line to the cluster. It's in the cardisc if you want the procedure.
That's a known issue with the Auto Spiders. TSB 40.93.04 has a fix which involves running a dedicated 12V line to the cluster. It's in the cardisc if you want the procedure.
Correct me if im wrong, but in your `74 speedometer is mechanic not electronic, and to its functionality you dont need to have any power, unless yours is modified. So in this case I cant imagine how bad ground can couse jumping effect in speedo?This has happened periodically with my '74 Spider (manual)...mostly around the time I had some ground issues (inconsistent starting, speedo jumping...sudden failure of throttle cable and hood release cable). Cleaning and tightening the various grounds seemed to alleviate the problem...could be a coincidence though...as a good car wash also seemed to fix things!
This has happened periodically with my '74 Spider (manual)...mostly around the time I had some ground issues (inconsistent starting, speedo jumping...sudden failure of throttle cable and hood release cable). Cleaning and tightening the various grounds seemed to alleviate the problem...could be a coincidence though...as a good car wash also seemed to fix things!
Uh yea, improving the ground on a mechanical speedomenter isn't going to solve much. Replacing the hood cable will though...This has happened periodically with my '74 Spider (manual)...mostly around the time I had some ground issues (inconsistent starting, speedo jumping...sudden failure of throttle cable and hood release cable). Cleaning and tightening the various grounds seemed to alleviate the problem...could be a coincidence though...as a good car wash also seemed to fix things!