How To: Vtec Pressure Switch Bypass

[Ludin203]

Ok so this took me a while to figure out when i did my jdm swap and i know some people will need this when they do theirs because i was left confused and with no vtec on my jdm swap for 3 days!!

This bypass procedure is used for those JDM vtec motors that dont come with the vtec oil pressure switch like this one...




now if your like me, you dont have an oil pressure switch laying around or a usdm vtec solenoid and if your really like me then you dont have a harness with the plug for it anyway..

When referring to the pins in the tutorial, look at this key:


so first thing is first:

UN PLUG YOUR BATTERY...

now, go down to your ecu and take your cover plate off and disconnect your ecu from the harness.

next grab plug "A" (the biggest one) and find pin "A4", the wire looks like this... its green with a yellow stripe


now cut it a couple of inches up the wire, strip both ends that you just cut and then wrap em together like so. remember to cut it up the wire a bit so you have enough room to strip it...duh..



ok, now grab plug "D" (the middle sized one) and get pin "D6" and do the same thing to this wire. its a light blue color.




ok now take both of those wrapped wires and wrap them together like so...



make sure its nice and tight and tape it up nice and snug with electrical tape.

remount your ecu and put the wires away nicely like so...




and make sure your vtec solenoid is plugged in with the vtec wire ( the green and yellow one) and your all done.

now you should be able to engage vtec without the need of the oil pressure switch.


some notes to understand about this bypass: when bypassing the oil pressure switch, essentially you are telling the Ecu that the vtec is working because there is sufficient oil pressure going threw the vtec solenoid after it has been activated by the ecu, thus the ecu is thinking the vtec is working the way it should because the vtec solenoid is open and there is oil and pressure going threw it. in the case you have done this bypass and there is not enough oil pressure to activate the vtec mechanically, you will not kick a code 22 like your supposed to. you simply will not engage vtec and will not trip a code. so if you notice you are not able to crack vtec some time after you have done this bypass and theres no check engine light, stay out of vtec rpm's and check your oil pressure first and continue trouble shooting from there.

[mark11017]

bump but if you understood how vtec actually works inside the head by using oil vallys and pressure to lock the rockers you wouldn't want to bypass the oil pressure switch which is a safety for the motor.. sure it will work but if your low on pressure damage can be done just do it right and get the switch ;)

[Ludin203]

yes, i understand completely how the system works, but in some situations like mine where you dont have a vtec harness, oil pressure switch, or even a damn clip to go on the switch even if u got one and wired it up, then this will work fine. the only way i could ever see this causing "damage" (correct me if im wrong) is if the vtec solenoid were to engage when there is not enough pressure and just...not send any oil threw the ports in the rocker setup to push the keys to lock into the vtec rockers, thus not activating vtec. but all in all i had this bypass since day one and it worked fine...and even when i was low on oil pressure it still did not activate anyway.. probably from another variable in the vtec dependency/safety system .

[Slim]

Did you make this "How To"?

[mark11017]

Yes it wouldn't activate because the oil pressure is what locks the arms by putting pressure up against pins, no pressure means it can't lock it's like trying to put up weight you can't handle in a sence, you could go to the junkyard and pick up everything you need to do it the right way for cheap, other then that nice write up.

[Ludin203]

as i do recognize this, im going to put a notice on the bottom of the how to. and thanks. :)

[Ludin203]

Did you make this "How To"?

essentially, i took the pictures and wrote it out. but i did not "create" or "discover" this. i just had a hard time finding out how to deal with this problem and how to do this , so i thought it would be nice to have it here on ctvtec.