Rev meter not working with conversion

[MrOizo]

Hey peoples!

Just wondering if anyone has had trouble with the tacho not working particuarally after a conversion.

my supra was originally a JZA70 obviously with a factory 1JZ.

When i have changed to the 2JZ the tacho stopped working. Weird thing is when i start and when i shut the engine down, it jumps a few notches on the tacho...

followed the supras.nl wiring and have checked it several times. :/
soooo anyone know what could be the happenings here?

 

[tissimo]

What harness did you use? The MKIV Supra (usdm 100% sure, assume the JDM is the same) uses the ECU to drive the tachometer. What you need to do is run a wire from the IG- on the Diag plug (right by where the harness runs into the firewall on a usdm car) and connect it to the stock tach wire in the dash wiring.

edit: supra.nl wiring is wiring the ECU outputted tach signal (ll1 #29) to the IG1 #11 tach signal. Thats why there is movement but it doesn't work.

 

[MrOizo]

What harness did you use? The MKIV Supra (usdm 100% sure, assume the JDM is the same) uses the ECU to drive the tachometer. What you need to do is run a wire from the IG- on the Diag plug (right by where the harness runs into the firewall on a usdm car) and connect it to the stock tach wire in the dash wiring.

edit: supra.nl wiring is wiring the ECU outputted tach signal (ll1 #29) to the IG1 #11 tach signal. Thats why there is movement but it doesn't work.

Cheers for the reply. So this is wrong for my setup?
running a wire from the -IG should sort this also. i am out of town at the moment but will give it a go as soon as i am back.

thanks.

 

[tissimo]

Cheers for the reply. So this is wrong for my setup?
running a wire from the -IG should sort this also. i am out of town at the moment but will give it a go as soon as i am back.

thanks.

Yes it will fix the tach. The JZA70 tach runs from a signal directly from the ignitor (same IG- Signal in the Diag block) rather then the ecu's signal of the jza80.

 

[MrOizo]

Yes it will fix the tach. The JZA70 tach runs from a signal directly from the ignitor (same IG- Signal in the Diag block) rather then the ecu's signal of the jza80.

Cheers for that!
Will get on to it as soon as i have a spare few mins

Thanks.

 

[suprastanger507mgte]

I agree with Tissimo. This is how I have it. I run a wire from the diagnostic/check box Tach signal to the black wire on the M1 connector for Tach.

 

[mischief7m]

I agree with Tissimo. This is how I have it. I run a wire from the diagnostic/check box Tach signal to the black wire on the M1 connector for Tach.

rather than starting a new thread, i figured i would ask this here.

my tach on my 7mgte to 1jz swap is not working, i have signal on the ignitor, but none on the same wire in the car. my question is can i run my tach off the same lead that my SAFC takes signal from? or would this be too much added resistance?

sorry if thats a stupid question, but any help would be really appreciated.

 

[MrOizo]

Thanks guys! Hooking to -IG and then to gauge solved my problem!

Just putting most of it back together now. exciting!

Have to sort out the electric fan and then its cruise-able