I just swap a h23a blue top vtec engine into my 97 prelude . Everything is perfect , run perfect . Except that the swap came with a obd2 B dizzy. I rewired it to my obd2 A harness but here is the problem. An obd2 B dizzy doesnt have a RPM out Blue wire to send the signal to the cluster. Instead in an obd2 B car they used from the ecu a rpm output to connect the cluster.

Since my setup is obd2 A from my 97 prelude How can i connect my Blue wire ( RPM signal )

Do the RPM is generated from the TDC + or something. I tried CKP + since the wire was blue but no luck , its not it.

There is the only thing missing from my swap that dawm rpm blue wire.

Where do i need to tap this wire to ?

 

an other thing , some of you will probably say how dont you use the dizzy i had from my old h22 engine that came from the car .

I couldnt since this car was using the CKP/TDC from the oil pump like an external crank angle sansor, it is not integrated into the obd2 A dizzy with external coil ... JDM dont use such thing . its all integrated into the dizzy.

So i rewire the CKP/TDC from the obd2 b dizzy into the connector that was doing to the crank angle sansor ... work pefect.

I rewired the cylinder possition from the obd2 b dizzy to the old dizzy connector .. work perfect ...

Also connected the icm signal .... and power....

Missing blue rpm wire...

thats almost it !

 

If someone need to know since nobody seem to know it.

RPM signal (blue wire) = ICM - Ignition ouput siginal ( yellow/green)

voila !