so i installed my tach and tach adapter from autometer as instructions called for. wired the tach adapter into the coil as required. and per thier website its wired correctly. now my question is, it said not to worry if the indicator rest below zero as it is a air core indicator, whatever that is, and when i got it it rested at 6 oclock. when its powered, my live wire will say the engine speed is 600-1000 and the autometer tach displays about 100 rpm, and at about 1800-2300 it displays about 350-400 rpm, and higher then 2800 it displays about 500-600 rpms. anyone ever have this problem, never installed a tach before but i did it according to instructions.

tach is a z series 0-8k tach, 2 1/16" and the adapter is model number 9117 tach adapter.

any help would be awesome

 

I don't know about the tach you have, but most aftermarket tachs are universal for 4, 6, and 8 cylinder engines. If you have it wired for the wrong number of cylinders it will give false readings.

 

that was the first thing i checked, and it is infact a correctly calibrated indicator for v8 output...

also the voltage is correct because a incorrect voltage would indicate higher then correct output

 

fixed it, autometer's instructions had the wrong wire, they want you to wire it so you only get 1 cylinder, which would make me realize my 1/8 numbers....now i get about 200 rpm above actual but the indicator is only 52 mm so its not a big deal and the needle is close so i can deal.