hey everyone, i recently put a CA in my little coupe and ever since my tacho (not origonal prolight from motorquipe) has stopped working. it was working when we took the A12 out but isnt working now. The auto elec wired it to something, then i tried wiring it to pin 7 (red and yellow wire) on ecu which is supposed to be tacho signal but it still not working. any suggestions would be great cheers.

there should be 4 wires off your tacho
Black-earth must be earthed well
light
- coil terminal
dont know what it does but it goes to a female plug that has 6 ports put this in the port bottom left port off the back of the ignition
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*goes in this one
p.s. write back with the colours of the wires

Quote:Not a Datsun 1200 Coupe tachometer. It is not connected to the coil (unlike most tachos).

For details, see Wiring - Tachometer

yes, the 12v feed to all four coils needs to be passed through the tacho.

It is not like a normal tacho that counts just one cylinder.

yes the tacho had four wires
red to 12v ignition
black to ground
white to lights
Green to tacho signal? thats the prop ive got what is the tacho signal. it is negative on the coil for the A12 but i has a CA now so it should come from ecu or somethin.

perhaps you should try the green wire to the injector ground wire or something?

thats the problem with new engines there all.... electric and stuff as soon as something happens you have to ask or get it done by someone who knows what there doing! like my dads toyota SR5 I look under the bonnet and scratch my head!

So you're running the factory ECU?

Factory ignition/igniters?

Pin 7 is the right one for the factory tach, but not a Datto tach (as you've found out).

HERE is one solution using 4 diodes. Let me know if you need a diagram of what he's on about

that does make sense you take the signal from each of the four coils and send them all to tacho. now its just a matter of finding the negative. i take it you run four wires with each wire having a diode in it then join them together

Yep - the negatives are all the outputs from the Power Transistor module.

Be careful to get the diodes round the right way.

Heres a doctored wiring diagram: