Tachometer Wiring Question

[2ndGenGuy]

Sort of a general wiring question about tachometers... I know they need the negative coil signal, and the ground, but do they also need a 12v connection to actually power the tach up? Do points type / electronic ignition tachs make any difference?

Basically, I've got a spare 78 Accord tach sitting around. I'm trying to put it in a Ford Festiva because the Fesitva is going in the 24 Hour of Lemons and we have a spending limit. It would be nice to use spare parts I have sitting around to put in the car so we don't have to spend $30 on a tach.

It's got 3 wires on it, Blue, Yellow and Black. Black is definitely ground since it goes on the body of the "motor" in the tach. I am guessing (but not sure) that blue goes to the negative on the coil, and the yellow is switched power? Does anybody know for sure? Is the 78 Accord points type or electronic?

Thanks for the he

[Hazwan]

I am not sure about yellow but blue definitely went to negative side on the coil.

[2ndGenGuy]

I am not sure about yellow but blue definitely went to negative side on the coil.

Thanks yeah that's what I thought. I don't wanna wire 12v to that yellow wire and fry the thing, but I guess if that doesn't work, I'll just be buying a tach anyways...

[Hazwan]

Let me check them up!

[Hazwan]

Yep, yellow wire went to the fusebox, and are connected to everything that requires +ve in the cluster, and I'm 100% positive (no pun intended) that it is positive.

[2ndGenGuy]

Fuck yeah! 78 Accord Tachometer running in a 1992 Ford Festiva Race Car! Thanks for the help man!

[Hazwan]

PICS and VIDS of the tach in action!!

[2oodoor]

some have illumination too, which would be 12v switched

[Dr_Snooz]

I'm pretty confident that '78 was an electronic (ie: no lousy points) distributor.

[tomatofiasco]

24 hours of lemons omg this is awesome, are you driving? those ford festiva's are pretty insane hoon machines, you'll need the tacho for advanced warning of the torque tsunami that will, without precise modulation, propel you into a once-distant buick. or tercel. it will occur completely without warning and a wheel may even come off like a red shell and clobber someone, hopefully an opponent. watch out anywhere between 2000 and 5000RPM [depending on service history], you'll want to mark that range on your gauge face with hazard stripes because you never know when the MONSTER will AWAKEN...

you probably already know this though i thought the electronic ignition happened from '79 onwards, but i am probably wrong.

[1GCustomAccord]

those ford festiva's are pretty insane hoon machines, you'll need the tacho for advanced warning of the torque tsunami that will, without precise modulation, propel you into a once-distant buick. or tercel. it will occur completely without warning and a wheel may even come off like a red shell and clobber someone, hopefully an opponent. watch out anywhere between 2000 and 5000RPM [depending on service history], you'll want to mark that range on your gauge face with hazard stripes because you never know when the MONSTER will AWAKEN...

Yeah, the 1.1L engine can really bring overwhelming power!

[2ndGenGuy]

24 hours of lemons omg this is awesome, are you driving? those ford festiva's are pretty insane hoon machines, you'll need the tacho for advanced warning of the torque tsunami that will, without precise modulation, propel you into a once-distant buick. or tercel. it will occur completely without warning and a wheel may even come off like a red shell and clobber someone, hopefully an opponent. watch out anywhere between 2000 and 5000RPM [depending on service history], you'll want to mark that range on your gauge face with hazard stripes because you never know when the MONSTER will AWAKEN...

you probably already know this though i thought the electronic ignition happened from '79 onwards, but i am probably wrong.

LOL! Oh man, you think that's nuts, we swapped in a 1.6 liter Mazda B6 engine (single cam). It really is a tire shredding torque monster. At least for that chassis. It's also a tail-happy, body-rolling, oversteering, beast as I found out this weekend. We took it to an autocross, and I managed to spin it out twice. We also found all of our awesome oil leaks on our freshly installed engine, which the other autocrossers weren't too fond of. :P It was only a few drips, just the rain that made it look worse than it was.