I am running a 20 Valve in an AE71 with a Microtech LT10S with the X4 Igniter Box

 

All runs ok, except it will not work with the factory tacho dash. The tacho worked perfectly before the Microtech was installed. There is some suggestion by the person who installed the ECU that my tacho is stuffed but I will have to check to rule this out.

 

Has anyone had this problem before and what was the workaround?? Is it possible to have the factory tacho working?

 

I have the Microtech Dash Display which has tacho function so not overly fussed but I like when things "just work".

 

Also, any tips on where to take it in SA to get it looked at?

 

Thanks

 

Luke

Theres a guy selling his tacho dash for this exact reason, i wonder if you bought an aftermarket tacho and fitted it in place of the tacho if it would work :P

 

Travis

Is it working at all, but is doing all sorts of strange things like jumping all over the place etc?

Is it working at all, but is doing all sorts of strange things like jumping all over the place etc?

 

Yeah it does work and jumps all round the place.

 

At times it hovers around where the Microtech Dash says the rpm is, but not accurate, and at idle well it just does not move at all. It may have something to do with calibration of the dash tacho to speak the same language as the Microtech Signal.

have u hit up microtech themselves?

I know in the bluebird I used to own, everyone had trouble with the signal from a CA18 ECU talking to the stock tacho, as the signal is quite different.

 

A common fix, and one I've seen for other similar problems is to install a resistor in the signal line to the tacho. Try a 10k ohm resistor and see what happens.

I know in the bluebird I used to own, everyone had trouble with the signal from a CA18 ECU talking to the stock tacho, as the signal is quite different.

 

A common fix, and one I've seen for other similar problems is to install a resistor in the signal line to the tacho. Try a 10k ohm resistor and see what happens.

 

Thanks.

 

I also found some info on Toymods yesterday which explains it as a common problem and some possible fixes.

did u fix this problem luke??? if not when did u wan2 meet up for this sale?? pm or msg me

oh and on ur issue my mate had a aftermarket tacho in his ss n it worked fine put it into an older car didnt work @ all think something to do with current or different signals or something not 100% but think thats what he ironed it out to be??

you probably need to make a tacho signal booster to make the old school tacho work.

Those old tachos are designed to measure the back EMF voltage spike from the ignition coil as an RPM pulse, but modern tachos, and most modern ECUs, produce a square wave 5-12Vdc signal pulse.... not enough for the old school tacho to register as an RPM pulse.

 

Build yourself one of these.

I've done it before for a 3SGTE in an ST162 with a Microtech LT10s and X4 ignitor (coil per plug).

 

http://www.toymods.net/forums/showthread.php?t=22574

 

Toymods is the king of tech info yo.