wiring a rev counter

[rallye69]

thinking of getting a 2nd hand vdo rev counter , how easy is it to wire on t25, done it on a Golf mk2 years ago ?

[itchyfeet]

Easy
Any Rev counter needs fused ignition 12v and ground which you can pick ip from many places but stereo is easy

Then you need the feed from the negative of the coil, this is green and goes to the multiplug on the dash and also via the fusebox easiest to use a scotchloc on that

If you drive at night you may want to wire up the backlight to the sidelights

[kevtherev]

Or if it's a derv then the alternator for the trigger wire

[rallye69]

cheers, just need to find a decent one now

[MidLifeCrisis]

Not sure that an '81 will have the wiring for the rev counter ...... I know my '84 does not .....
Has anyone got a nice clear pic of where the correct connection on the coil is?

[itchyfeet]

Ok never occured to me it wasn't there on early vehicles
You don't really need a pic there are only two terminals on the coil
One is black and has ignition 12v and connects to the + terminal the other is green and connects to the - terminal
Its the green - you want

The green is switched to negative by the ignition module ( or points on a 009) and each time its switched to ground a spark is produced (actually when its disconnected spark is produced)
Rev counter just counts these switching cycles

As said diesels don't have coils so the alternator generates a signal for the revcounter

[kevtherev]

cheers, just need to find a decent one now

I fitted one



from Demon Tweeks, eaasy fit

[Tufty_B]

I'm also thinking of adding a tacho, but I was looking at replacing the right hand clock in the instrument pod rather than adding an additional pod/clock.
I'd like to know people's reasons for choosing to add a standalone tacho rather swapping out the clock in the existing pod, is it just the cost?

[kevtherev]

Nope it's a nightmare.

[itchyfeet]

snap

no holes drilled position

[ScienceBoy]

Where's a decent place to get a meter? They all seem to cost a bomb.

[Tufty_B]

Nope it's a nightmare.

Is it not just a case of taking the instrument pod off and unscrewing the back and swapping the units over?

[itchyfeet]

Where's a decent place to get a meter? They all seem to cost a bomb.

Assume you mean rev counter paid £40 for that tim one off ebay new with postage

[kevtherev]

Nope it's a nightmare.

Is it not just a case of taking the instrument pod off and unscrewing the back and swapping the units over?

to fit it yes.
to make it work no.

[Tufty_B]

Nope it's a nightmare.

Is it not just a case of taking the instrument pod off and unscrewing the back and swapping the units over?

to fit it yes.
to make it work no.

Looking at the Bentley, it seems all the tacho needs on the T14 plug are connections:
3 Earth - brown
8 Ignition positive - black
9 Ignition coil - green
I guess in reality, actually wiring it up could be a mare.