Please help.
Just want to double check on the correct tachometer connections for my ute as it will not go.

There seems to be the 2 wires coming out of tacho (yellow with red trace), and black.

As it has had an engine swap to an A15 there seems to be no factory wiring nearby to connect to, so I will have to rewire from tacho back.

This may be a stupid question but which wire goes where in regards to the coil.

Thanx Guyz.

http://www.shoeys.com/diag/dat110_1.jpg

It's inline between the IGN and the POS+ side of the coil..but before the resistor.

I know it works in series, but It may also work in parallel. Which would stop the tacho being a point of failure in the 12v path to the distributor (mistake..should say coil).

Cheers,
Chris

Isn't the IGN 12v and the POS 9.5v? That would be a steady signal. If so, it should be the IGN and the NEG side of the coil (the side of the coil connected to the dizzy).

The Datsun Supplied wiring diagram doesn't lie

Chris

Yeah mr ddgonzal there isn't any actual connection of wires or power into the tacho, it is a loop of the power supply to the coil resistor that the tacho needs to work. It works off induction, basically like and inductive ammeter!
( this is if it is the datsun tacho! other types of tachos most people have seen work off a negative pulse from the coil negative)

This double post thing must be contages!

Also sorry Buff as i forgot to answer your question!
Firstly looking at the datsun wiring diagram datsun never used a yellow /red wire at all so i am guessing yours has had repare or someone has run a wire for the tacho!

ON the coil there should be a black wire going from negative to the distributor and a black / white wire to the coil positive.

On the back of the tacho should be 2 black /white wires no others!

Yep phunkdoktaspok is dead right mate!

I had the exact same trouble a few months ago... went out bought a second hand tach' for the ute...

When you look at the back of it you'll see like a little white plastic sleeve that the wire does a 'loop' through so there should be two bare ends to this....

Now one end goes to your negative on the coil... the other end goes to your neg on the dizzy..

To test which ends go to which without doin a permanent connection... What i did and it worked was...

Unplug the wire running to the tag on the outside of the diz' then strip and wrap one of the ends around this 'tag' and place the dizzy wire back on. Then put the other wire (the other end of the wire to the negative of the coil...

This should DEFINATELY work like this... that other wire that's floating around by itself won't do much... i guess it's like an isolating earth or something...

Anyways give the dat a rev...

If no response don't swap the position of the wires around but instead... note how the loop is formed on the actual tach' and do the reverse loop of it... and try again...

(u should c what i mean when you examine the back of the tach')

Yeh i guess the idea is to create a 'loop' and that's what's happening... tach----coil-----dizy---tach...

Well i'm sure someone will have some more tech' explantion of it...as this is a bit crude but it worked for me....

You might want to crimp the wire into the dizzy wire and do the coil wire properly once satisified...etc..

Good luck!

Cheers

Thanks, you are right. I've got the US 1972 wiring diagram here, and it shows the tacho as having two BW (black with white) wires, one connected to IGN+ from the fuse box, the other to the coil ballast resistor + side. As stated above.

I had an aftermarket tacho which worked on the negative side, as did my Tune-Up tach. Although in my 1200 I ran an early Celica tacho (it kinda fits in the same spot in the 1200 Sedan dash. It also had a cool anti-glare cone-shaped lense).

Datopower you stated that i was dead right but then you go and state that the wire is infact from the coil negative to the dizzy negative but in actual fact nissan wiring diagrams show it is ign+ to coil resistor+ as I stated and ddgonzal also stated.
Yourway might still work but since the voltage going through the wire you mention is lower than 12V as it has passed through the ballist resistor and then the coil I would think that this would give an inacurate reading on the tacho!
It would still fuctuate correctally as a normal tacho but since the current is lower the tacho would read a lower rpm then the engine actually is doing.
But it is posible to adjust the tacho to compisate for this but it would be easier to just use the original wires.
Like I have stated in an old topic nissan provided the correct wires in all the datsun 1200's produced and if you look at the wiring harness directally behind where the tacho is positioned you will see some coloured tape holding down the black/ white wire which is allready fitted with the correct male and female terminals to connect to the loop on the back of the tacho.