Hey i just swapped the jdm b18c 98 spec type r motor and tranny into my 01 usdm type r. I am using the usdm engine wiring harness that connects to a jdm b18c 98 spec type r ecu. It is connected via a OBD2B->OBD2A converter. My problem is that vtec doesn't seem to be kicking in at the usual ~5800 rpm. Actually it doesn't kick in at all. The motor itself seems to be running pretty smoothly and idles perfectly. The vtec just wont kick in.

There is an extra connection(colored green) on the usdm engine harness that connects to what i believe is the oil pressure sensor near the vtec solenoid. The JDM motor doesn't have this sensor so it remained unplug. Does the JDM motor need this sensor to engage vtec?

I want to know how I can get my vtec to work again. Thank you.

 

Yes your motor needs a oil pressure sensor for vtec to engage. No oil pressure no vtec. If you are in desprate need of vtec you can easily hook it up to a toggle switch or any type of switch. All you have to do is send 12v to the vtec solenoid and BAM theres vtec.

 

you need the oil pressure sensor.

and did something happen to the USDM ITR motor?

 

So if i swap out the oil pressure sensor or the whole vtec from the usdm motor, how will that green connection connect to my jdm ecu because the jdm motor didn't have this connection? thx.

 

actually JDM motors don't use oil pressure for vtec. double check your wiring. you should be fine with your JDM ECU

 

Are you using the USDM or the JDM ECU?

IF you're using the USDM ECU you'll need to switch out VTEC solenoid to the USDM one, the JDM doesn't have oil sensor. You'll also probably throw a 1337 code using the USDM ecuwith a JDM motor, so you'll need to either do this fix: http://technet.ff-squad.com/ckftrick.htm or change out the oil pump to the USDM one as well for the CKF sensor to fit somewhere.

If you're using the JDM ECU than I doubt the extra sensors or VTEC solenoid are your problem, as the older ECU shouldn't be looking for the sensors that are unplugged.