I have been reading on this Tach mod. Im upgrading from a 3.0 to 3.4, why should i need to change?

when i installed a V6 in my celica i just used the camry tach. same what MR2 guys do.

but since im going V6 to V6, why?

and all the threads i searched have no pictures. all dead links.

 

Can't tell you the why, other than the signal is different and your tach will get fried if you don't do it. As far as pictures....

https://www.yotatech.com/forums/f131...ach-mod-85960/

or

https://www.google.com/search?q=3.4+...1DJCah0gjlM%3A

 

It has to do with the difference in voltage. The resistor make the signal a usable on to the 3.4 ECU. Read enough swap threads and you'll see it necessary for the tach to work. Don't mess with what works!

My guess is that in your previous swap, you either didn't change the ECU or the ECU used the same signal as the cluster was outputting.

 

From my 91 4Runner:

Unmodified tach:


Modified tach (look at the blue resistor added at the bottom center of the tach):


EDIT: It's a 10K ohm resistor.

 

^^^^ once again, you came through. Thanks so much.

 

Thanks for the pictures, I did this about 10 years ago but couldn't remember exactly where to put the resistor.