Need help hooking up tachometer

[tylerMM95]

I have an aftermartket tachometer that id like to hook up but i have no idea how to do so, i figured id watch some youtub videos but id rather have a direct answer for my vehicle. Also under the hood it says the rpm's at "curb idle" should be "750+100 rpm" and im not so sure what that means, i think im idling a little high probably 900-1000 but i also have yet to set ignition timing since replacing the head gasket so i have to do that next, anyways thanks in advanced for the help everything is much appreciated😃

[tylerMM95]

Heres the tach, its nothing special but good thing i pulled it from my 87 civic EA before i sold it or else id be SOL because i dont have the funds for a new one haha

[tylerMM95]

15493

[geezer101]

Kerb idle should mean base idle after the engine has reached operating temperature. The +/- is the acceptable normal deviation from that idle figure. As your truck came with a factory tach option, there will be a signal wire in the loom behind the instrument cluster. Someone will either hit you up with a link or they'll just give you the low down. :thumbup:

[tylerMM95]

I haven't found any info on how to hook it up through the signal wire behind the instrument cluster but a buddy of mine said to just hook the green wire to a12v power source(battery?) them ground the black wire and that the red one goes to the constant flow wire on the ignition coil. This seems correct to me except hooking the power wire straight to the battery, id rather hook it up where it comes on when i start the car (maybe through the fuse box???) but im not sure if thats necessarily safe or how to attach a wire to a fuse without any adapters. Thanks Geezer101 for that bit of info on the wire behing the instrument cluster; im definitely going to look more into that more.

[geezer101]

Yeah, don't hook it up live straight off the battery. It won't be circuit protected (have a fuse) and if the wire rubs through on anything you already know what'll happen. Hook it up from a live source when the ignition is on only, not on accessory.

[royster]

Yeah, don't hook it up live straight off the battery. It won't be circuit protected (have a fuse) and if the wire rubs through on anything you already know what'll happen. Hook it up from a live source when the ignition is on only, not on accessory.

I hooked mine up directly to the battery, but only after installing an in-line fuse to protect it.

There is a connector on the firewall (or wheel well) for the optional tach, but I'm uncertain of how to hook it up.

I opted to mount mine on the cluster visor for minimal-eye-movement visiblity.

15510

[Fordubishi]

Ok an aftermarket tach will have 4 wires, Red to Ignition, Black to ground, Green to Coil Negative, White to instrument lighting. Run a wire to the negative post on your coil into the cab.Do not hook the Red to a constant positive as it will charge the stepper motor and burn it out as it's getting no tach signal. Ground the black to any metal under the dash. You can either tie the white into the ignition or lighting to back light the gauge.