The original tach in my 75 Esprit was very lazy and wouldn't rev past about 1700 rpm.
I bought a new reproduction from OER and it behaves exactly the same way. To eliminate the possibility of a wiring issue, I connected an Autometer tach to it and it works great. I even ran a separate ground. No change. Is it my rotten luck that I got a bad tach? Seems strange it behaves exactly the same as my original. I contacted OER and they feel it's likely the tach that's bad. Damn. Now to decide whether to put my dash back together so I can drive the car in the meantime or leave it apart and wait another 3 weeks for a new one. At least the clock worked on the new tack (it's integral on Firebirds)
I've only had the car for just over a month. It hasn't worked right since I got it. There's no switch etc to convert from 6-8 cyl. It does act like it's in a 6cyl mode though!
Todd, since the LeMans and Firebird tachs are almost identical I have one for the Firebird right here on the shelf, The clock is not in it right now. Let me know if you want to try this one. It is a 6,000 rpm scale with redline at 5,000 rpm.
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Ray White, Toronto ON
Formerly - The one and only 1973 LeMans 454 "Astro-Jet"