When I first key on, everything is mint. After being in VTEC for more then about 10 seconds, I get a CEL and VTEC stops working until I key off/on again.

This could be very simple... I dont have a VTEC oil pressure sensor, it didnt come with my engine and I just grounded out the wire... I couldnt imagine how it would matter tho since I would think the oil pressure sensor is just a switch.

Is that the problem, or is it something else? BTW I have tried 2 different ECUs and it does it... so its something in the wiring / solenoid

 

If your running a stock ecu then that computer needs to see the oil pressure or its going to freak out. The computer makes sure everything on the car is perfect before going into vtec, or staying in vtec. The computer is shutting vtec down because it isnt seeing the oil pressure that it should. So the computer THINKS vtec isnt work because no oil pressure, causeing your problem.

Get the pressure switch and try again.

 

My car does it when I get a little low on oil it is your vtec oil pressure sensor or a lack of. Get that and it shall be fixed

 

i just dont understand how it could be the pressure sensor.. since i have the wire grounded, the ECU thinks oil pressure is always high enough, which is why i dont have a constant CEL and no VTEC all the time... like before I grounded that wire.