After Market Gauges

[muddy_munke]

I have recently brought a ute to get round in and it didn't have a tacho. At 100kph it sounded pretty loud so thought I'd throw one in along with a water temp gauge and a oil pressure gauge. (Nothing boy racer and ricey either.)
Now everything is sweet. But the Tacho is designed to be hooked up to a car with an ECU.
My ute doesn't have an ECU, it's Carb. So after some research on the net, I thought I'd try what was suggested. That was to just hook the wire up to the Negative point on the coil. So after doing this the tacho works. But its way out. It reads 10,000RPM with only a minor push on the go pedal. I have selected the switch on the back to four as told to as it has four cylinders..
Anyone got any Ideas?? Is it simply that it just won't work or do I need to get an adjustable resistor and have it set up properly by someone special??
Cheers Daniel

[rowinz]

Can't answer your particular question, but places like jaycar.co.nz have tacho kits you can buy and build. They'd probably have a carbie one...

[muddy_munke]

Ah thats an interesting point. I might investigate to see if I can modify a sender or something. Cheers

[Mattman]

Sounds like the tach is designed for a low level input from an ECU or ignitor wheras your coil will be giving it a full 12v signal that it probably won't like.

Jaycar should have a converter that you can put together to modify the signal.

Matt.

[muddy_munke]

AH Matt, Your the man. I will investigate tommorrow and let you know how I get on. Cheers.