Tacho Isnt Working, 260Z 1977 Wiring Diagram

[Lach450]

Hi guys,
I have a 1977 260z and the only thing which is not working is the tachometer. I have spent two days trying to work it out but going from a wiring diagram which doesn't have the correct colours is quite hard and using a multimeter and everything seems to be connected to eachother! The only wiring diagrams i can find are the 280z 1977 an the 1974 260z which is are very different with there colors. 
If anyone could point me in the correct direction it would be greatly appreciated! 
Thanks, Lachlan. 

[WA240Z]

Have you recently changed to electronic ignition? If so the old system doesn't work too well with electronic ignitions. You may need to have the old circuitry inside the tacho swapped for a digital one, its quite straight forward and relatively inexpensive. A decent gauge shop will do it in a few days.

 

If there has been no changes make sure you have a good 12V supply and the signal wire from the coil and resister are in tact. I can scan a copy of the wiring diagram I use one Monday when back at work if it may help.

[Retro Z]

Maybe the tacho is just faulty

[Lach450]

It started working this morning but is not very accurate so it's a possibility I might send it to a shop, how much would I cost for a digital gauge internal swap roughly?

when I connected a green/white wire to a blue wire and ran a black/white wire to the + on the coil it worked!. But the coil is now only getting 9v when running not 12v, is there another wire that's meant to run to the coil for supplying 12v when running? I don't have a blue/black like some of the diagrams show for a electronic distributor being a 77.

Thanks for your help! Lochie.

[scott]

setup up a relay that feeds power from the battery and use your old wire as the trigger switch

[PB260Z]

But the coil is now only getting 9v when running not 12v, is there another wire that's meant to run to the coil for supplying 12v when running? I don't have a blue/black like some of the diagrams show for a electronic distributor being a 77.

Thanks for your help! Lochie.

I am pretty sure the coil is only meant to get 9V when running. The ballast resistor drops the voltage, it is bypassed when the key is in the start position.

 

Cheers

 

PB

[Lach450]

I am pretty sure the coil is only meant to get 9V when running. The ballast resistor drops the voltage, it is bypassed when the key is in the start position.

 

Cheers

 

PB

I have bypassed the ballast resistor and still 9V at the coil, is there another resistor possibly? if so where would it be located? I would like to keep the wiring neat without a relay but if I have to I will run one. Thanks for your time and sorry for all the questions this wiring is confusing me the previous owner has just cut most of the wires!

[zeds4ever]

On page six (6) in the electrical section there is a complete wiring diagram that NZeder posted to help me out some time ago . By the way did you take the resistor out that was originally fitted for the points dissy as this can cause problems , it was intended to reduce the voltage when starting up to protect the points set up & is not required for electronic igntn which is a full 12vlt set up, also using a stronger coil helps  .

When I set my 280ZX dissy up in my 76 260Z the tacho worked fine . 

 

                                                    Regards : Alan .

Edited January 29, 2017 by zeds4ever