I hope someone can help me with this - I know a Haynes manual would probably answer this, but mine's still on order at Amazon (grr).

Car: 1992 Mini Sprite 1275cc. Has "Traveller" style 2-gauge binnicle (speedo, temp, no tach).

I just bought a tachometer at the Goodguys show and the wiring looks pretty simple: one red wire to positive battery, one black wire to ground, one green wire to coil negative terminal and you're good to go.

However, before I start running wire, I wonder:

1. I know a 3-gauge binnicle was a OEM option with the 3rd gauge being the tach - does this mean that there's a lead already in the OEM instrument panel wiring harness connected to the coil ground terminal that I can splice into? If so, what color is it?

2. Assuming that the classic does not have a handy battery positive terminal right under the bonnet like the new MINIs have, I was thinking that I'd just splice into a lead coming off the fuse box. The instructons do not say to putthe red wire on a SWITCHED positive, so which one of my 4 fuses wshould I tap into? I believe that the top fuse is a switched line, but I also believe that the other 3 are always-on. Can someone verify this and/or recommend a better place to connect the red wire?

3. In case I DO end up having to run the green wire to the actual coil negative terminal, is it marked on the coil? I believe that the coil positive wire is white and the ground is white with a black stripe - can someone verify that? I'll gator-clip the tach to the coil briefly to test it before I start drilling holes and running wires in the dash...

4. Ground should be any screw that's into the sheet metal - I got that covered...

Thanks in advance!

 

I'm not going to bet the farm on this, but from what I can tell from one of the many diagrams in the Haynes book:

The coil lead should be White w/black stripe.
You may have a 3 conductor plug at the dash end with a black ground lead, the white/black coil lead, and a light green w/org stripe from the ign. switch.

I'd suggest a look at the coil end and see if you have 2 white/black leads connected to it: one for the tach, the other goes to the distributor.

Regarding the fuse: if you don't have the harness described above, the fuses are (from the top):
1: hot when ignition switch at pos 2 (i.e. turn signals)
2: always hot (unswitched)
3: Hot at positions 1 & 2 (i.e.windscreen wipers)
4: switched thru light switch.

You'd want to use a switch fuse for the tach. I put mine on #1 fuse

At the coil, connect the tach lead to the lug that has a lead going to the dist. Should be a white/black wire.

Hope this helps

 

Yeah that does... So if I do have a 3-plug connector at the dash end, can I tap into one of those wires for the tach, or should I run a fresh lead to the coil lead bridging to the distributor (the white/black one)?

Also, did you upgrade the #1 fuse at all, or is the extra resistance generated by the tach negligeble?

 

Hmmm... I have TWO wires with black stripes... there are 2 connectors on the top of the coil (both white with black stripes) and then a harness on the bottom with white wires... Where should I hook in for the tach do you think?

 

One of the White/Black wires goes to the dist. The other one SHOULD go to the dash area for the tach that your Mini is not equipped with. And that wire should end, I think, in a 3 prong plug or other connector that WOULD have gone to the tach if your Mini had one. If you can find that end and its connectior I think you won't have to run any wires. That connector should have all the connections you need (except for maybe the dash light). If your tach has a light and a separate lead for it, you'll need to splice that into the rest of the dash lights. Just pick one - they're all connected together. No need to change the fuse. It is, or should be, a 35 amp fuse. Plenty heavy.

 

Sweet... So I'll trace that line and see if one goes up into the dash - hopefully one does. I think the wire on the right in my picture goes to the distributor - it meets up with the white wires and they merge into a rubber insulated bundle - you can see this in my photo. I think the one on the left hoks back and goes towards the firewall.

I'll plan to tap into the #1 switched fuse for the red wire - sounds like a plan.

Thanks!

 

Also - does anyone have redline/suggested shift RPM values for the 1275, single-carb engines? My tach has a little needle I can set - I'd prefer to know the redline value over the suggested shift RPM.

Thanks again!