HELP!! Tacho signal is dead....needle jumps when RPM wire earthed
 

Can anyone help me out with any suggestions or a good auto sparky.

I was stuffing around with my tacho and somehow I thinK i have created a bad connection on the RPM wire.

If I take the wire that I have spliced into the RPM wire under the dash and touch it to an earth point it causes the needle to jump around.\

This is the standard my99 tacho in the dash....

I have also tested from the rpm output from the ECU and its exactly the same ... needle jumps and signal strength is not there.

Cheers

Simon.

you should only have 3 wires eh 1 power 2 earth and 3 signal if you have had all the wires disconnected then check you have the right one in each posi and the earth is good. what was wrong with it before you were playing with it ?? what sort of multimeter do you have ??

Ive got an automotive multimeter.

But the problem is not hte shift light its the STANDARD TACHO... the standard one is no longer working as the tacho signal is dead.

Don't use the tacho then :P Just shift when it hits the limiter, every gear :D

if you have a tacho function on your multimeter then hook it up to your signal wire this will eliminate a faulty tacho if it still does the same thing possibly a fault in the ecu or input into the ecu unlikely tho, unless it has been shorted. where are you picking up your rpm feed from coils or ecu??

thanks for the reply packa.... i have hooked up the multimeter and where there was a signal before on the rpm wire out of the ecU there now is nothing.... so what can u do if you have shorted the output from the ecu? does a LINk ecu have fuses in it? have i just blown an internal fuse???

If I earth teh rpm signal wire from teh ecu (I spliced a wire into it for testing) then the tacho needle moves a bit and then goes back to zero.

no worries polar .im not familiar with link ecu but they dont usually have fuses inside ecu maybe a burnt diode would need t inspect the board . how electronically minded are ya?? or if you know a computer or tv repairer they should have the knowledge to check for burnt components. does everything else work in the dash ??

yeah everything else is good.

and the rpm signal going to the link hand controller is fine..so car runs fine... just dont have the tacho output anymore.

it must be in the computer take it to whoever you bought it off or try petro jet they check most of our computers

West Coast Auto Electrics in north perth replaced a burnt diode and chip in the computer for $130...

Got them to fit fit the tacho and some big Foff air horns today. Thanks for the tips packa