Tach Wiring

[bdpalace]

I pulled this out of my dash and it wasn't connected to anything. Does it matter which wire goes to the ignition and which goes to the coil? Also, is there supposed to be a ground wire coming off the solder at the 3:00 position? The original engine was replaced with a Chevy 4.3L...will this stock tach work?

Thanks in advance.

 

[JR74CJ5]

I am almost positive the tach will work fine with different motor.

As for the wiring, i believe it does matter which goes to coil and 12v power... But... Im not sure which is which on yours. The ground may have been supplied through mounting bracet, though also not positive on that...

I would try to look up a wiring diagrahm for the tach by a model number. If cant find model number on it, id look for the manufacturer or google search until i found model number... Then look up wiring diagrahm.

Jr

 

[bdpalace]

The bracket is a plastic cap that screws onto the back of the tachometer so I don't think it is providing any ground. Is there any way to test the this with a multimeter to figure out how to hook it up? I just got this Jeep a couple of weeks ago and I'm trying to fix the small stuff before tackling the rust. Thanks again!

 

[madmax087]

I've installed two different aftermarket tachs before, and they both had switches to adjust the tach for 4, 6 or 8-cyl applications. Not sure how these stock tachs work, but if they are calibrated to a specific cyclinder count from the factory you might be SOL. But, like I said, Im no expert on those, just speaking to the experience I've had.

 

[jeeperz]

 

[bdpalace]

I figured it out. With an HEI, the tach is connected in series with the ignition wiring. I traced the ignition wiring, spliced the tach in, and it works like a champ. Time to !