adam Posted August 7, 2016 Share Posted August 7, 2016 Gday all, Hope you guys could give me an idea into what could be happening. Bit if background, I have a '73 240z running an L28 with a 280zx electronic distributor, MSD 6A ignition, stock tacho with MSD tacho adaptor/booster. My issue is the tacho fluctuates with every indicator flash, drops dramatically when the headlights are on (relays installed) or if my heater blower is on. Note, driving/revving does not change, purely a tacho reading issue. I have just bought a new battery and had a 280zx internally regulated alternator installed about two years ago. Any ideas what is causing this fluctuation? It's bloody annoying! Cheers, Adam Quote Link to comment Share on other sites More sharing options...
WA240Z Posted August 8, 2016 Share Posted August 8, 2016 Hi Adam, One thought is the tacho is quite sensitive to fluctuating supply voltage, given you have covered a lot of bases with the (+) positive side of the supply, I would be checking the quality of your (-) ground connections. Try taking the negative supply to the tacho direct with a new wire to a nice clean ground point. Poor ground connections unfortunately dont raise there ugly head until there is load on the circuit making tracing a real pain in the neck. Hope this helps, and good luck. Billy Quote Link to comment Share on other sites More sharing options...
adam Posted August 9, 2016 Author Share Posted August 9, 2016 That was my next step Billy, cheers. I am all ears for any other suggestions. Quote Link to comment Share on other sites More sharing options...
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