had a search through the wiki but couldnt find it does anyone the trigger wire for the 120y tacho
cheers

in the 1200s its black with yellow trace i think

http://datsun1200.com/modules/mediawiki/index.php?title=Wiring

half way down the page

If a 120Y (B210) is equipped with a tachometer, the factory tachometer is wired as a part of the ignition system and sends out a pulse to keep the engine firing, however without the tachometer connected the engine will not run with the key in the on position (before the start position) on the ignition switch. If someone was to remove the tachometer the two black wires with white stripes that connect to the tachometer must be connected together.

thanks mate i wasnt sure if the 1200 and 120y wiring was the same
im trying to hook it up to the ca18det computer and see how it goes

i wouldnt recommend that as the 120y tacho works differently and is not meant to be computer controlled
as in it works as a loop (8 volts or something)

just get the wiring loom for the ca18 that includes, injectors, sensors, pressure switches, etc..
this stuff http://www.240sx.ca/i/UNCUT-sr20de_L.jpg
and dont use the other wiring loom that goes inside the cabin (use the 120y one)
then carefully study the 120y ignition circuit and adapt it to the ca18

Ok so it's nearly time to wire up my tacho. Is there an idiot-proof instruction somewhere? These are the wiring diagrams:

http://datsun1200.com/uploads/photos/9757.jpg
http://datsun1200.com/uploads/photos/9758.jpg

Not very clear but it looks like:

Black with White stripe - ignition switch negative?
White with Black stripe - ignition switch positive?
Red - no doubt a powered wire, must be a flow-through from White/Black above?
Black - no doubt an earth, must be a flow-through from Black/White above?
Red with Blue stripe - this seems to run the dash lights, flow-through from ignition switch also?

Ok well it seems like I was close-ish.

But, there seems to be two black/white wires & no white/black one.

Can anyone shed some light on points with question marks?

Attach file:

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  tach labelled.JPG (156.35 KB)

Someone will correct me if I'm wrong but I think the 2 black/white wires are the same wire.

One end to ignition other end to coil which is why the car wont run if you remove a tacho and dont join the wire back up.

It runs in a loop I guess inside the tach body and the tach picks it up by induction to move the tach needle.

There should be a wire behind the dash cluster that has a spot for both ends of the two wires to be plugged in.

Ok that's a great start, confirmed what I thought & what I'd read elsewhere.

As I'm running a CA18DET and a Haltech PS1000... where should these two black/white wires be connected to?

The other three wires seem to be a no brainer - ignition switched power to the red/blue and red wires, and permanent earth to the black wire.

It can only be wired up in the way described through the wire in the dash cluster so I guess suck it and see.

Do you not have the connection behind ur dash?