Nice diagram - by the way thanks for the pedal it turned up the other day - much appreciated

Can i still hook up the coupe tacho if ive got a CA18DE.

What will i have to do different to whats in this diagram?
seeing i dont have an A-Series wiring loom

Cheers Henry

Now, without trying to offend anyone, I believe that the wiring Diagram is incorrect, you wont get a pulse signal (which is required for a Tacho to work) from the + side of the coil. All tachos are wired on the negative side. Hence the White/Black wire. the tacho is wired in series on the 1200, if you wire it in parallel the car wont start, because that will just earth the points (effectively how a kill switch works) Hope this helps.

Dattodevil without trying to offend, you are actually incorrect.
Not all tachos are wired to the negative side of the coil.
Datsun tachos work off induction. ( basically magnetism )
As in the diagram there is no actual physical connection of the tacho to the coil.
The positive supply to the coil is looped through the tacho. As the coil creates sparks, the coil is charging and discharging, this is shown in the current running to the coil through the positive wire as going high then low. This create a strong magnetic field and then a low magnetic field. This magnetism induces a pulse into the tacho to make it operate.
I dont know how to explain it any simpler. Hope this helps you understand, if not let me know.

Currently I have my tacho wired on the negative side and it works fine, once I get my ute completed I will try it as in the diagram. If it works then well and good. I do understand that it works of induction, I just never realised that the slight current fluctuation on the + side of the coil would be enough to trigger it.

Edit: my apologies, The tacho can go either side if the coil, I had the picture of the test light running from + side and of course it will stay on because it is creating its own earth. Thanks Steve

Good point. Since it's current flow (not voltage) it shouldn't matter which side of the coil the stock tacho is on. Just as long as it is not grounded! It's just that Nissan made it easy to wire into the + side by putting the b/w wires behind the dash.

What are the two wires on the right side for?


Wiring article

yellow with red trace [from memory on the colour of the wire] is for the +12V to energise the winding inside the tacho, so that the needle can sweep and the other is ground.

Thanks benny, I can confirm. They are Ground/earth and IGN. My tachometer is working now.

have this early tach and its not working, how can you determine if its defective or not. I followed what's on the diagram and for some reason i cant get it to work.