Quick tach question

[Element]

Got a tach and wired it up tonight; only problem is, when I start the truck, the tach goes backwards instead of acting like it normally should. I hooked the tach lead up to the wire coming off the ignition coil (wire without a connection in the picture). Did I hook the lead to the wrong wire?

 

[4X4HIGH]

That is correct. The wire on the coil without anything hooked to it is the tach lead.

 

[Element]

Wonderful....so now I have to figure out why in the hell it's not working.

 

[4X4HIGH]

If memory serves me right you should have a black ground wire, red keyed hot wire, green IIRC tach signal, and a white for the light.

What brand is the tach? Also some smaller tachs have a wire that needs to be cut depending on 4, 6, or 8 cylinder use.

 

[Element]

It's a Sunpro, mini version, with a switch on the back for cylinder selection...she's set at 8 now, ground is a good one to the frame, and the green wire goes to that connector. Only thing I can think is the wire I spliced into for a 12v switched isn't actually a 12v switched (wiring is ghetto from previous owners). Don't have the white light wire hooked up yet because I'm not 100% sure which fuse on the block (or wire in the dash) would work for that.

 

[4X4HIGH]

You can tie into any of the dash light wiring for the light in the tach this way the light isn't on until you turn the headlights on. Also you could use the Batt lead on the distrubutor for the HOT lead to the tach. I really don't like grabbing that source for HOT but at least for testing purposes it will work.

 

[Element]

Is there a hot spot on the fuse block I could tie into for the hot wire?

 

[4X4HIGH]

Yes there is but i'm not sure which one it is. Get yourself either a test light or a DVOM and check for the location.