brand new autometer tach is junk?!?!?!

[UnderdogGN]

hey guys, just bought a brand new autometer pro comp 3.75" tach.....theres only 4 wires coming out of it....i read the directions a thousands times and it doesnt work wtf!?!?! green wire went to my MSD ignition box tach terminal, black went to the negative side of the batter, red went in to the fuse that has 12V power when the key is on, and white went to the lights. The light in the tach works fine but when i fire the car up the tach needle just sits where it has been sitting and doesnt move....anyone got any ideas or did i just waste $150 on a brand new junk autometer tach!?!?!
thanks in advance

 

[jtfairlane]

Are you 100% certain (not just making an "educated" guess) that the tach is receiving ignition hot, switched 12v?

 

[UnderdogGN]

im pretty sure because i put a test light where i hooked into....it lit up when the ignition was on and turned off when i turned the ignition off....ive tried it in two different spots like that

 

[795.0pacecar]

Have you tried running the signal wire straight off the coil?

 

[HISSIN50]

The multiple sparking will cause the tach to read incorrectly if run off the coil, but I suppose you would see that it works at all.

I'd recheck the connection on the box for the tach hook-up. Then, as mentioned, use your meter to confirm that you have 12 volts into the tach and that your ground is good (implied if you daisy-chained the ground wire for the illumination, but double check).

Good luck.

 

[smr]

x2...A friend just went through three new tachs thinking he bought junk but it wound up being his msd wasnt putting out any tach signal...

 

[MustangMatt1966]

x2...A friend just went through three new tachs thinking he bought junk but it wound up being his msd wasnt putting out any tach signal...

ding ding ding...also check to see if the tach is switched to V8 mode..some have 4/6/8 settings i think. I cant exactly remember if that was for my shift light or for the tack...but check and make sure... I think the tach is working properly, but it is the connection to the coil that is keeping the tach from working..let us know what it turns out to be.

Matt