Toyota Guages

[beebee]

Can anybody tell me what I have to do to get the tacho in my Hilux dash to work?

The tacho worked fine when I had a 22R motor. Then I put the 3RZ-FE (2.7L) in and I can't get the tacho to work again.....The computer has a tacho out which will work fine when I put it to an aftermarket guage or timing light (with tacho function) but not with the std tacho. What's the go??

My temp guage has also stopped working for no apparrent reason but at least they used to work.

[dumbdunce]

hey beebee, does the 3RZ have a distributor or coil packs? if coil packs, does it have 2 or 4? either way you have to get the same number of diodes as the number of 12v inputs to the coil packs and connect them together in a star configuration with all the cathodes connected together and connected to the tach feed, and the anodes each connected to the coil pack inputs, this will give a 12V square wave similar to what the tach used to get from the coil of the 22R - the ECU tach signal is probably 3 or 5v which is good for instruments designed for it but no good for a 12v tach.

another possibility is that the ecu tach signal is switched to ground instead of a pulse of positive voltage so it could pay to measure it with an analogue meter or a CRO - if that is the case it may be possible to drive the tach off it directly with some fiddling around with the way the connections work.

might give you something to go on, anyway.

cheers

DD

[beebee]

Thanks for that.

I tried to test the polarity of the output with a digital meter but it didn't work - obviously the analog is the way to go. I'll check this out first then try the other method you described.

Thanks again

[dominic]

not sure about the tacho but yout emp gauge may not be working due to incorrect sender.
if you still have the old motor see if you can put the old temp sender in.
even if you get the one on the new motor to work it may be reading incorrect on the gauge.
so it may show your motor over heating when its not or running fine when its over heating....

cheers
DOm