10 replies to this topic

[Shylos]

I have a wire coming off my loom near the alternator that after looking around seems to be for the tachometer. This is a 1990 City.
 
I could only see one WB on the wiring diagram, but this thread in particular seems to be exactly my situation and suggests the tachometer.
 

 
I think I know what I need to do, but just want to make sure I don't make any stupid mistakes...
 
Am I good to remove the spade on the current black and white wire connected to the coil (blue spade in this picture) and add a new spade with both that wire, and the above wire connected, to reconnect to the coil in that same spot?
 

 
I just want to make sure I haven't massively misidentified the wire or am hooking it up to the wrong place. Thanks for any help

[Lplus]

I wonder what the black and red wires are on the negative and positive terminals.  If they are the wires to an electronic spark system on the distributor, and no other wires connect to the distributor I wonder what the white/black wire with the blue spade does.  Certainly the rev counter signal feed is a white/black and it would go on the negative terminal.

[Shylos]

Are they not standard? I have never touched the wiring so didn't think to check what is already connected. I'll do some searching. 

[GraemeC]

That does look to have been messed with in the past.
The red and black would indicate an electronic ignition conversion, but then the fact ballast wire (the one with the writing on) and the crank bypass wire (white/yellow) are still in place would suggest that your ignition system isn’t configured well.

I take it the tacho working currently?

Personally I would remove the existing white/black and see if the car still runs OK. If it does replace it with the other white/black and see if your tacho now works.


If that’s all successful I’d then investigate whether you do have an electronic ignition conversion and then if you should feed the coil with a full 12V and indeed whether the coil is the best one for your system.

Edited by GraemeC, 17 May 2024 - 09:52 AM.

[Shylos]

That does look to have been messed with in the past.
The red and black would indicate an electronic coil conversion

 

That unlocked a memory... I have a feeling this had an electronic ignition conversion years ago and it looks like that's the case: 

 

 

Is it possible the white and black wire was no longer needed after the conversion?

[Lplus]

 

That does look to have been messed with in the past.
The red and black would indicate an electronic coil conversion

 

That unlocked a memory... I have a feeling this had an electronic ignition conversion years ago and it looks like that's the case: 

 

 

Is it possible the white and black wire was no longer needed after the conversion?

 

With a normal ignition there are two white/black wires - one from coil negative to distributor, the other from coil negative to rev counter.  They can be fitted to the same spade connector at the coil.  Which ones you have sticking out of the loom is impossible to tell at this point.  Assuming none go to the distributor it is even possible the wire with the blue coloured cover connects to the other white/black wire with the black cover. The blue covered wire might even be the one to the rev counter.

[Shylos]

Thanks for the information, I need to read up some more on how these systems work.

 

Once I get the radiator back in, I will do some testing of whether the tachometer it currently working and go from there. 

 

I'll poke around and see if I can find any other loose ends, too...

[croc7]

At some point, maybe lead from coil to Lucas 65D module?

[Lplus]

At some point, maybe lead from coil to Lucas 65D module?

That isn't a 65D distributor.

[GraemeC]

 

Is it possible the white and black wire was no longer needed after the conversion?

 

 

Very possible.  There were a number of ways over the years that this has been configured from the factory.  You may find that the white/black you have on the coil actually splits in the loom - one to the rev counter and one to the spade you have found, which would then have had the fly lead from the points plugged into it. Sometimes the wire is spliced, sometimes it is joined with two wires into one connector on the coil, sometimes it is two separate wires.

 

It certainly looks 100% like you have and electronic ignition conversion.  It is very likely that the +ve feed to your coil is wrong and not giving you the best - it should be one ignition fed 12V supply (ideally on a white wire).

As I said, it may also not be the best coil for the electronic ignition system.

[croc7]

 

At some point, maybe lead from coil to Lucas 65D module?

That isn't a 65D distributor.

 

Didn't say that it was a 65D distributor, mentioned that it could have been used for one in the past.  Unless one has owned a mini from new, who knows what sort of mods have been made.