Rustyfriend Posted August 13, 2009 Share Posted August 13, 2009 Hey guys, I would just like to start off by saying I have tried searching random combinations of "turbo, swap, tach, signal, 280z" and I haven't really found any concrete info as to how to get tach signal after the turbo swap, just "maybe" and "i think" statements. I am aware I need to hook something up to the negative side of the coil, but I am just not sure on what wire it is and/or how to test it. I have tried looking at my Hayne's manual, but I honestly cannot read the tiny print that is there and I am not 100% sure on what I am looking at. Any advice or direction would be greatly appreciated. -thanks, Adam Quote Link to comment Share on other sites More sharing options...
thetremendoustim Posted August 13, 2009 Share Posted August 13, 2009 Hey thanks man i was just gonna post something http://forums.hybridz.org/showthread.php?t=104715&highlight=l28et+tach+wiring this guy had the same question and no answer! So you've completed your L28et swap and you can't wire your coil to your tachometer in your S30? I have the same problem and I've tried different combinations. From what I gather I need some sort of under-dash resistor of some sort... P.S. Did you figure out how to wire the thermostat from the l28et to a S30 thermostat? That's my next mission and final mission is oil pressure unit before i'm takin my baby to the DMV and registering it! :mrgreen::mrgreen: Quote Link to comment Share on other sites More sharing options...
blu240z Posted October 4, 2009 Share Posted October 4, 2009 I had same problem do you have 75 or76 tach. Quote Link to comment Share on other sites More sharing options...
Rustyfriend Posted October 4, 2009 Author Share Posted October 4, 2009 I have a '77 and still have no signal Quote Link to comment Share on other sites More sharing options...
jyz77 Posted October 4, 2009 Share Posted October 4, 2009 what year wire harness are you using ? if its an 81, you take an all blue wire will connect to the - coil (that is in the same loom as the yellow/white stripe that connects to the ignitor ).. then from inside the car find the rectangular resistor that is mentioned above the light green wire will have a tach signal. the other way is to locate the original tach wire that is inside the engine bay already (if you haven't hacked it up. ) and just re connect the wire to the coil. if my memory is correct , that wire is all blue as well. hope this helps. Quote Link to comment Share on other sites More sharing options...
Rustyfriend Posted October 4, 2009 Author Share Posted October 4, 2009 I believe mine is an '82 swap. Quote Link to comment Share on other sites More sharing options...
cgsheen Posted October 4, 2009 Share Posted October 4, 2009 I think all S30's have the same Tach setup. My 74 260 and my son's 76 280 both did... When we did our L28ET swaps, it was just a matter of tying the lead from the turbo coil back to the original wiring. On ours (originally) it's a blue wire from the Coil negative side that's pretty much the end of the engine bay wiring harness. That harness starts under the glove box (passenger side cockpit) - (which is where you'll find that rectangular resistor, by the way...) goes through the firewall near the battery, continues along the frame up to the front of the car, along the frame in front of the radiator, and down the other side to the coil... On the S130, the wiring to the coil is on the opposite side. It's a small harness that disappears into the fender well near the coil and travels back to the cockpit by the ECU (at the drivers feet). It doesn't really matter if you used that small harness or not. You just need to get a connection from the negative port on the coil back to that resistor. If your original engine bay harness is there, just use the blue wire that ran to the coil originally. If you're using the S130 coil harness, take it's blue wire from the coil and connect it to the BLUE wire on the rectangular resistor (NOT the Blue-White wire - that goes to the Tach). The resistor is easy to spot - it's almost as big as your finger, in a rectangular case, and usually wrapped with black tape near the wires... (BTW, "carfiche.com" has the '77 FSM (and the '82 280zx FSM)... Just looked at the circuit and wiring harness diagram - as far as the tach and coil go, it's basically the same as my son's '76 280 (and my 260...)) Quote Link to comment Share on other sites More sharing options...
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