Tach wiring

[Skwerl]

Can someone post a picture of the circuit board for the tach in an LS400? I am putting a 1UZ into my 84 supra and I am trying to figure out how to wire the tach so it will work right. I know that MSD makes a tach adaptor, but I have heard that it is not always accurate. Any help would be appreciated.

 

[Peewee]

The problem is that the tacho in the dash is a 6cyl tacho.

You will need a 4 cyl tacho to make it work properly

 

[Skwerl]

So it won't work even with the tach adaptor?

 

[Peewee]

It will, but it will read 33% high (if the 1uz puts out an 8cyl signal) or 50% low (if the 1uz puts out a 4cyl signal)

You will need a tacho converter too.
Or have the tacho reconfigured.

The problem is that I don't know what the 1uz puts out, whether its a 4cyl or an 8 cyl.
I'd guess that it is a 4cyl.

Also, seeing as it runs a conventional ignitor/coil/distributor setup, I'd suggest that you wont need an adaptor at all.
The dash should be able to read the signal.

 

[Skwerl]

Well, the tach signal comes from only one ignitor, so it would make sense that it would read like a 4 cyl. How did you get your tach to work?

 

[Peewee]

I am currently using an Autometer Tacho, not the factroy one.
Plus, I am using an Aftermarket ECU, so the factory 1uz wiring didn't concern me.

But I will be doing a factory wired 1uz into an mA61 about christmas time, so I will be trying it then.
let me know how you go

 

[elhsupra]

Get the instrument cluster from a Celica. Identical instrument cluster but tach is setup for the 4 Cyl.

 

[Skwerl]

So it does have a signal like a 4 cyl? will that cluster fit in my 84 supra?

 

[Skwerl]

Also, how much are you paying for headers eric? Could you possibly get them to make 2 sets? I could send you the money.

 

[sideshow]

1uz has 4cyl output

so yr 6cyl tacho will read slower

you can either get yr tacho modified or you can

buy a signal converter

i make tacho boosters to suit the 1uz

plus i also have the signal converters

i used both these devices in a cressida with a 1uz and worked fine

 

[Zuffen]

Quite often manufacturers use tachos that have a switch on them to allow you to run 4 , 6 or 8 cylinder engines. Have a look on the back of the circuit board. I've come across a few over the years that have a switch.

You may be lucky and get away with a click of the screwdriver. The tach in my car (a Rover) is selectable so I just set it at 4 cylinder and away it went.

 

[cyberdiamond]

Has the VVTi also got 4 cyl output?

 

[Peewee]

vvti will have a 1 or an 8 cyl output as it runs coilpacks.