18 replies to this topic

[Doodling]

Changing the dash on my 1989 B reg Mayfair to a custom job. All the dials and lights are working apart from the rev counter.
I know the White/black wire goes somewhere and there has to be a feed and earth.

What goes where?
1. Earth?
2. ?
3. ?
I have tried a combination of the White wire from the ignition that goes to the voltage stabilizer and the White/black wire but all i get is sparks and the engine cutting out.

Edited by phil.lingard, 11 August 2009 - 09:00 PM.

[Doodling]

Any help anyone.

[robtheplod]

I'd also like to know answer on this one....

[minikidx14]

Im sure one of them would go to the coil, one earth and one for a backlight??

[Doodling]

The White/black goes to the coil but as stated all i get is a few sparks and the engine cuts out. I have tried a number of combinations with no answer.

[mk1leg]

Its possible that that revcounter could be pos+/earth thats why its sparking.............

[xBR4DLEY]

I dont fink u have a 1989 B because i have a 1983 A?

[Doodling]

I dont fink u have a 1989 B because i have a 1983 A?

V5 Document:
Date of registration 23/06/89
REG-Bxxx xxx
for ref.

[Doodling]

Its possible that that revcounter could be pos+/earth thats why its sparking.............

Any ideas what i need to do to correct the fault? Don't know about pos+/earth

[Simples]

Earth, Ignition Live and feed from negative side of coil, have no idea which is which though!! I'm sure they're -ve earth as I had one n my mini ages ago!

[camp freddy]

right i had one of these smiths, 1 to earth , with 2 and 3 you have to split the + wire to the
coil , connect terminal 2 to +wire feed and terminal 3 to the coil ( so the feed goes to the gauge
and back to the coil in a loop) hope this is clear.

[Doodling]

right i had one of these smiths, 1 to earth , with 2 and 3 you have to split the + wire to the
coil , connect terminal 2 to +wire feed and terminal 3 to the coil ( so the feed goes to the gauge
and back to the coil in a loop) hope this is clear.

If i get you then terminal 3 has the White/black wire that goes to the neg side of the coil and terminal 2 has the live feed from the white wire from the ignition. Cheers I'll give it a go tomorrow but i'm not sure if i get it fully lol.

Edited by phil.lingard, 11 August 2009 - 10:52 PM.

[dklawson]

As the last two post have mentioned, this tach is an inductive, Smiths RVI type tach. Before you go too far with your installation, does your car have electronic ignition? If it does, do not bother trying to fit this tach. Sell it and find the slightly later Smiths RVC type. (The gauge type is in small text somewhere on the gauge face). The RVC tachs are compatible with most ignition systems and connect to the coil with a single wire.

For wiring assistance, see Speedy Cables. Specifically:
http://www.speedycab...page34aaaa.html

You'll note that the back of your tach looks somewhat different than the one show at Speedy Cables. The Speedy Cables tach is an early aftermarket model and the induction loop is exposed on the back. Your gauge is a factory tach as fitted to later MGs and has a male and a female bullet connector on the back. INSIDE the gauge, those two connectors are connected to each other by a loop of wire. Your tach will therefore connect with one bullet connector to a switched terminal on the ignition switch, the other bullet connector going off to coil (+). The gauge case receives and earth connection. The spade lug on the insulated plate receives a switched, fused, 12V supply.

[Doodling]

Cheers helps a lot.
It is the old points ignition.
Quick question, the one bullet connector and the spade lug, can they be the same switched supply if not where would i get a switched supply from for the lug? Also fuse size would you suggest?

Edited by phil.lingard, 12 August 2009 - 12:18 AM.

[camp freddy]

right i had one of these smiths, 1 to earth , with 2 and 3 you have to split the + wire to the
coil , connect terminal 2 to +wire feed and terminal 3 to the coil ( so the feed goes to the gauge
and back to the coil in a loop) hope this is clear.

If i get you then terminal 3 has the White/black wire that goes to the neg side of the coil and terminal 2 has the live feed from the white wire from the ignition. Cheers I'll give it a go tomorrow but i'm not sure if i get it fully lol.

no you take the white wire off the coil to the rev counter and back to the
+ terminal of the coil