Just purchased a new aftermarket tacho with shift light to fit to my sons 120y coupe race car.
(problem).Connected it as per the instructions and found it does not show the correct RPM,(switch is in 4 cylinder mode)I have never come across this before.Any help would welcome.GREG.

bump

what is the needle jumping around.

The needle shows 3000rpm when the engine is idling and needle flickers.
multi meter shows it idles at 1500rpm which by my ear sounds right.

the tacho itself must be faulty , cause i got one of ebay brand new and it flickers and jumps but it is hooked up 100% correct. (cheap crapy brand)

What sort of ignition do you run? Coil pack or regular distributor?

also depends on if there is a switch on the back of the tacho that selects 4 6 or 8 cyls.

The tacho was off EBAY(shit),whent to Autobarn got another brand $120, wired it up and the same thing took it back and ordered a $290 Autometer tacho,wil try it next week hope it works. I herd that some tachos dont work on early Dattos.
The ign system is STD,just modified the mechanicle advance

my tacho instructions say:

black to ground
red to ignition switch
white to dash lghts (for light)
green to neg terminal of coil

it says connect green to the transistorised or capacitor discharge systems in accordance with ignition systems manufacturers instructions.


it is a $50 cheapy from supercrap but is fairly accurate.

i think gino120y has same one no problems there either.

I have the stock 120y tach and it agrees with my handheld tach at higher revs, but shows 6-700 revs higher at idle.