Guest bobs302z Posted April 19, 2002 Share Posted April 19, 2002 I have a 77280 I took old fuse block out and put a painless one in most of my wiring works but my tack is giving me trouble . does anyone have a diagram of the wiring right of the tach to ignition .Ihave a msd6al. I believe theres a green wire & a red&black that needs to be connected thanks Quote Link to comment Share on other sites More sharing options...
Guest scca Posted April 19, 2002 Share Posted April 19, 2002 how are you going to calibrate a factory tach to a v8??????? Quote Link to comment Share on other sites More sharing options...
Dave Posted April 19, 2002 Share Posted April 19, 2002 As I recall the JTR conversion manual says that there is a adjustment screw in the back of the tac that you adjust it with. Dave... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 19, 2002 Share Posted April 19, 2002 Apparently you are looking to connect the tach sensing wire to the negative side of the coil. I have a factory maunual for a 78 Z that there is a blue with white stripe wire that goes from the tach to the ignition coil and a blue wire to a 10 amp fuse.(black wire to ground).Apparently the blue- white stripe wire going to the (-)coil REQUIRES a 15,000 ohm resistor(1/2 watt/ Radio shack) connected into the blue white tach sensing wire.I reviewed the JTR manual and threw it down in disgust due to the confusing wire color references without stating 240 or 280 Z and then author Mike Knell complicates matters further by instructing to wire it all in to the positive side of the coil if using points and etc. Apparently the author needs to edit and update his instructions since it appears that his only recorded experience has been to modify the "guts of a 280 to a 240 tach" without much experience in actually using a 280 tach or wiring a 280 Z (or definitely not a Ford V8). I would say find the tach sensing wire on the tach harness which according to Mr. Knell is alleged white or black white or white black or all shades of graytone and install a resistor in it and fuse the "power" blue wire with a 10 amp fuse connection. I hope this helps and not confuses you further. If the tach needle is bouncing you need a resistor. Quote Link to comment Share on other sites More sharing options...
Guest bobs302z Posted April 21, 2002 Share Posted April 21, 2002 I got it to work this is how I wired it . tack wires green & red black goes to (green to blue witch I connected to 12v) (the redblack goes to blue white witch I connected to msd tack wire)Its seems to work ok with out resister .hope this helps other people. Quote Link to comment Share on other sites More sharing options...
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