I have a JDM H22a swapped into my USDM Si (H23 stock). I'm running a JDM P13, and using the USDM external coil dizzy.

My tach hasn't worked since the swap!
What wire sends the rpm signal?
Will running a USDM dizzy w/ JDM ECU be an issue?


someone please help me!

 

https://honda-tech.com/forums/honda-prelude-4/how-do-i-hook-up-vtec-h22-swap-2555489/

 

I found the wire you said, it runs to my VTEC solenoid... is that right??

 

yeah, thats right.

 

hmm.. so I'm back to square one then.

The blue wire is supposed to send the signal, so by my logic, with the test light being grounded on the battery, and poking the blue wire with the car running, I should get a signal to the test light right?

Because as of right now I get nothing that way, but if I put the test light on a power source and touch the blue wire, I get the light.

Its like the blue wire is acting as a ground, not a signal/power source...

 

I will ****ing paypal someone 5 dollars if they lead me to the answer to my problem. seriously.

 

test the continuity between the blue wire at the dizzy and the TCM using a multi meter, if thats ok, then test it from the Dizzy to the Tachometer connector. he blue wire splits somewhere in your harness, with each end going to either the tach or tcm, maybe that split is broken or shorting.

 

I'm going to feel stupid in the morning, but TCM?

I was thinking maybe I un-pinned the wire for the RPM signal when I was trying to get the damn H23 ECU out, what color wire is it/slot on the ECU side of the harness?

 

tcm= transmission control module, its just a solid blue wire all of the way through, according to my chilton book the tach wire doesnt go to the ECU , it goes to the tcu