Fitting Tachometer

Kent Casual Dubber

35 posts · joined Feb 2013 · 28 Apr 2013, 1:30 pm

#953242

Hi alll
i have purchased a Tacho and was wondering if anyone has installed one themselfs?
if they could give me any tips that would be much appreciated.
also i need to find a postive sourse that is turned on and off with the ignition? i dont have a multimeter on me so i need a bit of a hand with that?
cheers

Anthiron The Baja Rejuvenation Begins

4,936 posts · joined Oct 2003 · 28 Apr 2013, 1:37 pm

#953243

Green wire to Negative Coil terminal
Red wire to power source which is live when key is in On position (Wire it from the ignition switch)
black or brown wire to earth

Then you will have 2 more wires for the backlight.

Red wire to headlight circut
black wire to earth.

Usually they come with an instructional booklet. If the wire colours are different, just substitute the colours on your tacho (It should have a wiring diagram in the booklet)

Nicko

62/60 model bug eye baja bug, (Full Build in Progress)
1974 Chevrolet Luv
1970 MK2 Ford Cortina GT
1979 Yamaha RX125 Two Stroke tracker project.
2004 Harley Davidson Sportster XL Custom

Kent Casual Dubber

35 posts · joined Feb 2013 · 28 Apr 2013, 1:44 pm

#953245

Cheers Nicko.
i need to extend a few of the wires to reach the coil/battery, will need to use exactly the same size wire?

Anthiron The Baja Rejuvenation Begins

4,936 posts · joined Oct 2003 · 28 Apr 2013, 2:09 pm

#953247

Just use 12 gauge wire.

You won't need to wire the Tacho directly to the battery. Just to a power source that is live when the ignition is ON. IE: the ignition feed terminal on the ignition switch.

62/60 model bug eye baja bug, (Full Build in Progress)
1974 Chevrolet Luv
1970 MK2 Ford Cortina GT
1979 Yamaha RX125 Two Stroke tracker project.
2004 Harley Davidson Sportster XL Custom

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 28 Apr 2013, 8:31 pm

#953329

Just be careful of where you run the signal wire from the coil to the tach.
If it ever rubs through and grounds on anything metal the engine will stop.

vlad01 Compulsive Aussie Vee Dubber

4,270 posts · joined Jun 2010 · 28 Apr 2013, 10:59 pm

#953356

Joel wrote:Just be careful of where you run the signal wire from the coil to the tach.
If it ever rubs through and grounds on anything metal the engine will stop.

is that from experience?

71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 · 29 Apr 2013, 12:32 am

#953368

and don't power the tacho straight from the ignition switch. Always run things from the fused side of the fusebox.

Either have a look at the wiring diagrams for you year here The Samba Beetle wiring page

or if you aren't good at reading wiring diagrams let us know what year Beetle you have and we can tell you the fuse to connect too 😉

madness is in the eye of the beholder 👍

Anthiron The Baja Rejuvenation Begins

4,936 posts · joined Oct 2003 · 29 Apr 2013, 5:24 am

#953373

Psimitar is right. I should have mentioned. Run an in- line fuse.

psimitar wrote:and don't power the tacho straight from the ignition switch. Always run things from the fused side of the fusebox.

Either have a look at the wiring diagrams for you year here The Samba Beetle wiring page

or if you aren't good at reading wiring diagrams let us know what year Beetle you have and we can tell you the fuse to connect too 😉

62/60 model bug eye baja bug, (Full Build in Progress)
1974 Chevrolet Luv
1970 MK2 Ford Cortina GT
1979 Yamaha RX125 Two Stroke tracker project.
2004 Harley Davidson Sportster XL Custom

hellbugged 48's and straight cuts

5,080 posts · joined Apr 2003 · 29 Apr 2013, 6:06 am

#953374

vlad01 wrote:
Joel wrote:Just be careful of where you run the signal wire from the coil to the tach.
If it ever rubs through and grounds on anything metal the engine will stop.
is that from experience?

Yep

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 29 Apr 2013, 6:52 am

#953376

vlad01 wrote:
Joel wrote:Just be careful of where you run the signal wire from the coil to the tach.
If it ever rubs through and grounds on anything metal the engine will stop.
is that from experience?

Nope, I've always used factory wires in the loom for tach signal (72 on have them for the diagnosis circiuts) but anyone who knows electrical can tell you that grounding the points will kill the ignition.

Same reason I laugh everytime I see a thread on a VW forum why does my engine stall every time I put the car in reverse? 😂

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 · 29 Apr 2013, 11:16 pm

#953497

no I'm sure the reverse power goes to the coil negative 😂

madness is in the eye of the beholder 👍

Kent Casual Dubber

35 posts · joined Feb 2013 · 4 May 2013, 3:28 pm

#954119

I got the guage it in and works fine 🙂
thank you all for your tips ! 🙂

SunshineKarmann Casual Dubber

34 posts · joined Dec 2008 · 6 May 2013, 1:28 pm

#954404

If you find that your tacho reading is off and/or the needle is a little jumpy, you can wire up a diode in line with the negative wire from the coil (place diode closer to the coil end) to stop the signal rebounding and creating these issues. Worked a treat with mine.

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 6 May 2013, 4:13 pm

#954419

It's just a simple recifier diode, it can go anywhere in the line.

I started out fitting them at the coil too but the harsh enviroment of an engine bay gets to them eventually.
I started fitting them at the tach end and they were fine, no one has reported back any problems yet.

Most tachs these days are designed for a nice clean signal from the ECU not the fluffy one points provide.
An IN4004 diode cleans the signal up nicely.