9 replies to this topic

[WHarding]

Hi,

I bought a 1992 rover mini city 998cc and it came a tachometer but hasn't worked as far as I know, it has 2 connections coming out of the back of the dial but I don't know where they are supposed to go and connect to, anyone help me get this working?

Will

[the beasts]

earth and to the coil , but wait for a better answer from someone, a pic would help the next person.

[dklawson]

Indeed.  A picture will help quite a bit.  There were at least two types of Smiths tachometers used over the years.  A picture will clarify which you are trying to wire up.

[WHarding]

earth and to the coil , but wait for a better answer from someone, a pic would help the next person.

Indeed.  A picture will help quite a bit.  There were at least two types of Smiths tachometers used over the years.  A picture will clarify which you are trying to wire up.

I will get a picture tomorrow when I can, it's not a smiths tachometer, it came attached to the mini but I don't think it's original

[WHarding]

There are the pics, there is a free port on the ignition coil and a few loose wires around it but connecting the loose wires doesn't seem to work

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[Gremlin]

You need to trace that white wire with the black trace and connect it to the coil - terminal, then it should work as the light green/orange should be soldered in to the ignition controlled loom

[WHarding]

You need to trace that white wire with the black trace and connect it to the coil - terminal, then it should work as the light green/orange should be soldered in to the ignition controlled loom

I connected the black and white wire to the ignition coil but it just stopped the car from starting and then when I disconnected it the car starts straight away

[Gremlin]

to which terminal on the coil?

[dklawson]

to which terminal on the coil?

 

I know where you are going with that question but there is a bigger problem.  If you connect the white/black wire to the wrong coil terminal (coil(+)) the tach will not work.  If (as WHarding is reporting)  the engine will not start with the white/black wire connected to a coil terminal (either terminal) there is a bigger problem.  This indicates that the white/black wire has a short to earth OR the tach has an internal short. 

 

My suggestion for a test is to disconnect the white/black wire at both ends. Temporarily run a new wire (outside the loom) from the back of the tach to the coil (-) terminal.  If the engine will start with the external wire connected, there is a short in the white/black wire and you need to buy a new length of white/black and run it neatly between the gauge and coil.  If instead the engine still refuses to start until you disconnect the external wire, the tach has a short circuit and needs repair or replacement.

 

Before adding a new white/black wire (if necessary) make an additional check.  Look carefully at the wiring around the coil (sorry... I cannot tell from your picture).  Some looms include two white/black wires.  When points are fitted to the distributor, a short white/black wire goes from coil (-) to the distributor. The second white/black goes from coil (-) to the tach.  If an aftermarket electronic ignition has been fitted, that can leave (3) possible white/black wire ends in the vicinity of the coil.  Make sure (using a multimeter) that the white/black you connected to coil (-) is the same white/black you have connected to the back of the tach.  At the coil... locate any remaining white/black wire ends and tape them up so the cannot touch earth.

[WHarding]

 

to which terminal on the coil?

 

I know where you are going with that question but there is a bigger problem.  If you connect the white/black wire to the wrong coil terminal (coil(+)) the tach will not work.  If (as WHarding is reporting)  the engine will not start with the white/black wire connected to a coil terminal (either terminal) there is a bigger problem.  This indicates that the white/black wire has a short to earth OR the tach has an internal short. 

 

My suggestion for a test is to disconnect the white/black wire at both ends. Temporarily run a new wire (outside the loom) from the back of the tach to the coil (-) terminal.  If the engine will start with the external wire connected, there is a short in the white/black wire and you need to buy a new length of white/black and run it neatly between the gauge and coil.  If instead the engine still refuses to start until you disconnect the external wire, the tach has a short circuit and needs repair or replacement.

 

Before adding a new white/black wire (if necessary) make an additional check.  Look carefully at the wiring around the coil (sorry... I cannot tell from your picture).  Some looms include two white/black wires.  When points are fitted to the distributor, a short white/black wire goes from coil (-) to the distributor. The second white/black goes from coil (-) to the tach.  If an aftermarket electronic ignition has been fitted, that can leave (3) possible white/black wire ends in the vicinity of the coil.  Make sure (using a multimeter) that the white/black you connected to coil (-) is the same white/black you have connected to the back of the tach.  At the coil... locate any remaining white/black wire ends and tape them up so the cannot touch earth.

 

Thanks very much Doug for so much detail, the wires on my car are... well... lets say not good so its probably dodgy wiring as i have loose wires all over the place. I will keep trying to get this working

Thanks

Will