Tacho

[Guest peter2b2002]

I have an after market tacho, on the wiring i need to connect 2 wires, 1 to the neg on the coil the other one to the tacho out put from the ecu or the W connection on the alternator( i have a 2lt efi) Q my alternator only has 2 connections , a big one to the bat. the other one i think goes to the ign warning lamp, I cant seem to make head not tail of the Haynes wiring diag as it bears no relation to my wiring( ex sierra)an i can't make out which is the tacko feed from the ecu.

any help please. cheers pete2b

[Guest gordon_macnab]

Pete,

 

Don't know why you would want to connect the tacho to the alternator, all the tacho needs is a positive supply, earth and a pulse signal from the coil. If you've got the sierra loom I think the feed to the tacho is green.

 

cheers

 

Gordon

[Guest timswait]

Can't you trace the tacho input to the Sierra tacho and use that. I'm pretty sure Gordon's right and the wire is green, but failing that just look at the circuit printed on the back of the Sierra instrument cluster. The tacho has 3 connections, +ve, earth and pulse. Failing that, just connect it to the (low tension side !!) of the coil and it should work.