gjc5500 Posted June 16, 2007 Share Posted June 16, 2007 I am planing on running new ignition wiring. I have a crane cames ignition w/ msd blaster 2 coil. Attacted to the coil is 2 wires that run only to the ignition box, and 1 power wire from the balast resistor. I know that aftermarket tachs take their signal from the - side of the coil, my honda did too, so does our vette. where does the Z get its signal? Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted June 16, 2007 Author Share Posted June 16, 2007 anyone? Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted June 17, 2007 Author Share Posted June 17, 2007 Some one plz respond. i searched here and on google. i checked the fsm and cant find out how it works. Quote Link to comment Share on other sites More sharing options...
naviathan Posted June 17, 2007 Share Posted June 17, 2007 I thought the Z got it's tach signal from the "-" side of the coil also... Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted June 17, 2007 Author Share Posted June 17, 2007 no. the only thing on the - side is wire that goes to my crane box. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted June 18, 2007 Share Posted June 18, 2007 Aren't the early Zs kind of screwy where they get the signal from? I know this is a cop out answer but if you switch to a 280z tach you can take it from the "-" on the coil (just make sure to keep the stock resistor in the wiring). Mario Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted June 18, 2007 Author Share Posted June 18, 2007 If i was gonna swap the tach, id prolly go AM or Sunpro(lolz). I was wondering because i am going to run new power wiring for the coil that draws from a fused line strait from the batt thru a relay. and im very curious of where the signal comes from. is there a wire that goes to the dizzy or something? Quote Link to comment Share on other sites More sharing options...
2savage Posted June 20, 2007 Share Posted June 20, 2007 Diagram from S30 wiring shows the signal coming from the coil +ve. Quote Link to comment Share on other sites More sharing options...
rags Posted June 20, 2007 Share Posted June 20, 2007 I don't have it in front of me but I do remember the JTR book showing the tach signal changing from an inductive source to the negative coil terminal. I thought it was done in 73 but I'm not 100% sure.Someone will have to chek the book for you. Joe Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted June 21, 2007 Author Share Posted June 21, 2007 So if i run a different wire for power, my tach wont work? Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted June 21, 2007 Administrators Share Posted June 21, 2007 240 tach is current triggered (pos. side of coil) and 260/280's are voltage triggered (neg. side of coil), as are most aftermarket tachs. Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted June 21, 2007 Author Share Posted June 21, 2007 so when the power dropps it triggers it? Quote Link to comment Share on other sites More sharing options...
rjracin240 Posted August 24, 2007 Share Posted August 24, 2007 MSD sells a adapter that I used with my MS-6AL Tach works as advertised. Quote Link to comment Share on other sites More sharing options...
NZeder Posted August 25, 2007 Share Posted August 25, 2007 The points based tach's are a direct copy of the Smiths setup so they have a loop from the + side of the coil. Here in NZ our 260z (up to 1978) still had a points based dizzy so therefore this older type + loop tach setup. So given how hard it is to find a 280z tach locally I took my tach to a local smith instruments guys who was known to have a conversion kit that can upgrade the UK Jag Smith based tachs from the + loop type to the modern - coil type. So a few days later and a new circuit board my 240z (and 260z) tach have been converted and calibrated to the more modern - coil signal type. So much so is the Zed tach a copy of the Smith unit they even use UNC screws not metric like the rest of the car - makes you think that Nissan had a license to use these Smith style tachs in the cars in the first place. If you want to have the stock tach look I would contact a local speedo/tach/instruments shop and tell them you have tach that is a copy of the Jag smith + loop type and do they sell/do a conversion kit. I know the Jag kit works as this is what has been installed in my 240z tach. Hope this info is of use. Quote Link to comment Share on other sites More sharing options...
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