Tachometer Technical Questions

[Yoshioka58]

Hello everyone!
I have been looking for more specific answers on the tachometer resistor mod when swapping in a 3SGE Beams. I do not have an AE86 but own a RA65 Celica that I am engine swapping in a 3SGE Beams.
Like both stock engine 4AGE and 22RE, both ran off the ignitor negative terminal for the tachometer signal. I have seen where AE86 guys remove resistor R4 and stick in a 10k resistor in order to use their stock tachometer.

So my question is, what is R4? And what does it link together, 12v and signal?. Is it possibly to simply add a resistor inline of the tachometer signal or does it have to bridge in between 2 points and what 2 points would that be?

Thank you for reading, any information helps!

-Isaac

[gramacosport]

Hi
This will work on your car o aftermarket ecu

Thats on ebay
Some guys like Azril abu bakar( find it on facebook) are manufacturing some relays that work
Cheers
Juan


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[LittleRedSpirit]

[LittleRedSpirit]

On the ae86 you need a pullup resistor. Thats all the little thing above is, you can make one by taking the cap off any relay and zip tieing the contact to disable movement. You will find articles online about wiring this, and some ecu companies have documented the process.

[LittleRedSpirit]