Rev counter

[Burney]

Hi

I have a smyths rev counter, can anyone advise how to wire it up?

I have a wire from the coil and a positive feed does the other just go to earth?

Anyway I can test?

 

Ta in advance

[IanS]

Yes the third wire is an earth.

Test is does it work when engine is running.

[Burney]

Hi Ian

 

Thank you, I tried that and no response. When I bought the car it flickered at high revs but has never been right. Is there a way to test the signal wire or do I just get a replacement instrument? They are 100 nicka new so would like to find out if this one is definately beyond economical repair.

 

Kris

[Burney]

Might be a silly question but whats the differece  etween the +ve and -ve side of the coil?. I'm using the original cable but prehaps its been wired wrong all along?

[IanS]

+ve side of coil switches up and down for every spark.

-ve side is earth and does not therefore have any signal for the tacho.

[maca]

Back in the good old days of a contacts breaker fitted in the distributor then you had a live feed wire from the ignition to the coil +ve and a wire from the distributor contactor breaker to the coil -ve.

The rev counter was then feed from both sides of the coil wiring sometimes to a loop of cable on the back of the rev counter now that is old school days before those new fancy electronics were put into our cars.

Martin

[Burney]

If I put my meter on AC and connect to sender cable would it show a current when engine is running?

[Burney]

Update its reading now but seems to be about 50% lower than what it should be?

[MarkBzero]

What ignition system do you have, this would happen with a wasted spark system if not connected correctly.

[Burney]

Erm not sure there is a coil and a silver plate then dizzy

[IanS]

Is the tacho for an 8 cyclider motor?

I can not quite read the writing on the face.

[Burney]

Hi Ian it just has vf10cpc120001 as reference nothing to suggest 8 cylinder but that would explain the 50% under read.

I also just have 2 wires connected. A positive supply and the sender to the -ve side of the coil

[maca]

The wiring on the back of the clock shows a  battery + terminal a battery - terminal and the signal terminal.

Have you tried with all 3-wires conected? 

Regards 

Martin

[Burney]

Hi Martin I did connect the -ve terminal to the negative terminal on the battery and it didnt seem to work at all then.

The little corcuit diagram on the back doesnt make much sense to me though.

I'm going to try it again though cos that didnt seem to work so I disconnected off battery leaving the other wires connected (sender to coil and +ve supply). Shoved it in the dash and fired engine back up and then it came to life but only at about 50%

[Burney]

I thought the negative terminal might have just been for a bulb