Tacho troubles

[chrizer]

Hey all,
Putting the tacho dash in my corolla, connected my tacho output from my microtech to the IG- on the dash behind the tacho. Installed dash and tacho doesnt work. When I turn the ignition on to reds the needle jumps like it is getting power but no revs. Then went for a drive and discovered that the tacho works every time the blinker is going..
Whats going on need help???

Cheers
Chris

[DQIKST]

should the tacho be connect to the coil/igniter??

i dunno dont take my word for it

[BeRad]

usualy a tacho connects to the negative of the ignitior/coil...

Hen has done a good writeup on aftermarket ecus and tachos

if your trying to use a output on the ecu it probably wont work as it spits out a different signal to what the toyota tacho can inteperut(sp) and this is covered in hens article. but im not sure about the indicator thing ill find the article for you.

http://toymods.net/forums/showthread...rket+ecu+tacho

[The Witzl]

yep - you need to build the Wilbo tacho booster.

It works when your indicators are on because the back EMF spike can be picked up through the coil of the blinker flasher unit

[cooter]

i also had this prob. are u running a coil pack per plug with the micro tech? actually i dont think itd really matter if u were running waste spark. but yea i was told if u take put a wire on each of the earths of each coil , then put a diode on the end of each one and then combine them intio your 1 tacho wire. the 4 wires will take each coil pulse but they wont be able to interfere with each other.
littler easier than making that wilbo thinky. wether it works or not ill have to see when i get some diodes
cheers
craig

[The Witzl]

Both options work fine.

The only difficulty with going for the coil negatives combined with diodes is where you have mounted your ignitor - you will have to run wires from there to your tacho.

[cooter]

sweet cheers for confirming that whitzl
craig