Meph Posted August 25, 2009 Share Posted August 25, 2009 Is it possible to get a stock 240z tach to communicate with my aftermarket ecu? I have a positive 0-5v or 0-12v trigger wire I can connect but Im not sure how it should wire up to the existing gauge. I think there are two versions of tach's aswell, so if you have any ideas im all ears. Thanks Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 25, 2009 Share Posted August 25, 2009 The stock 240z tachs are current triggered - 260 and later are voltage triggered. This means that you need a "tach adapter" in order to get the early tach to trigger from an ECU. MSD sells one for about $50. But just an FYI, they're not very durable and somewhat temperature sensitive. Don't mount it in the engine bay or anywhere else that gets warm. Alternatively, you can just wire it to trigger off the coil as the factory did. It's been a while since I looked at the factory wiring diagram, but I'm pretty sure that the tach is wired in series with the coil. Perhaps someone else who's done this more recently can chime in? Quote Link to comment Share on other sites More sharing options...
Tommy Posted September 18, 2009 Share Posted September 18, 2009 I found a great deal on ebay yesterday, and went with a PS91 and HI-6 from crane arms, with their tach adapter. You can use the crane tach adapter with many different ignition systems. As mentioned, my tach didn't work as it's a L28 into a 240z (different tach trigger styles). I replaced everything for more spark to the triple webers, but more for increased reliability... but I've heard arguments from both sides on the reliability "advantage". Quote Link to comment Share on other sites More sharing options...
Fairlineguy Posted October 1, 2022 Share Posted October 1, 2022 Worth mentioning if you using a aftermarket ecu with wasted spark cop coils . Forget the ecu tach output If you power your coils through the original inductive loop tach wiring (same way the original coil was feed) you tach will work Quote Link to comment Share on other sites More sharing options...
DuffyMahoney Posted October 3, 2022 Share Posted October 3, 2022 On 10/1/2022 at 11:21 AM, Fairlineguy said: Worth mentioning if you using a aftermarket ecu with wasted spark cop coils . Forget the ecu tach output If you power your coils through the original inductive loop tach wiring (same way the original coil was feed) you tach will work yep! Works great, I would say mine reads maybe 300-500 rpms low sometimes, but I am fine with that. Quote Link to comment Share on other sites More sharing options...
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