I have a 95 Honda Accord that will not engage vtec it is the sohc 4banger. the check engine light is on and will not come off i have tried disconnecting the battery and pulling the ecu fuse. it all started when my speed sensor went out and i had to drive around like that for a while till i could buy a new one and after replacing the speed sensor i did the paper clip in the harness trick to flash the cel codes. it blinked the corresponding numbers for the vtec pressure switch i have replaced the pressure switch and the sulliniod and tried multiple times to reset the ecu and it still will not engage vtec. i have a limited understanding of hondas so i was hopeing for a little bit of help anything will be greatly appreciated. thanks.

 

When did the vtec stop working? What did you do or change just before that?
Check your oil level, low oil=no vtec.
Bad vss or plug (have you had any issues since you replaced it?)
Check/clean the vtec sol screen
Check vtec wiring voltage (use a helms manual)

 

if your throwing certain codes vtec wont engage . like i think one of them are oil pressure sending unit and knock sensor im not sure tho and i think all vss

 

+1 to everyone but most likely the oil not getting through will be the major reason. Check if your getting the oil flow up the the head correctly, if persay this was a mini-me swap you probably did yourself a while back and your now noticing you haven't been popping V-Tec then you probably forgot to remove the oil control jet off of the block, because the mini-me head has it's own jet and two jets won't allow Vtec to scream and perform with the right Valve duration that it is set to. Also, check the VSS and see if it's the right one you had on before. Check if the VSS is working by Test light troubleshooting it, seeing if it is sending it's info to the ECU and if it is being listened to and the ecu is allowing the switch to continue to work, check the oil lines for a leak also. Probably you might need a oil pump, if not, then you might need a oil filter do a inspection check in your car before anything. Good luck with everything.