ok, this is an interesting one...I have a turbo s2000 with an oil cooler. This setup has worked well before but now it is intermittent. Vtec engages if the car is off for a very long period of time (few days) and works for maybe three-five passes on the dyno. After that it does not engage. I have changed the oil several times and checked the oil levels consistently. The oil pressure reads fine, getting above 60 psi at WOT. I disassembled the vtec unit, cleaning the screen and such and it does trigger when applying 12volts with the unit out of the car. With it on the car and manually triggering it with a 12volt source it does not work when revving to produce oil pressure. The oil pump is also new and I am using regular 10-30 oil since the motor is relatively new.

I am using an AEM EMS to control the car. It is set properly and reads vtec engaging.Any ideas on this one? some of my thoughts initially was going to a heavier weight oil, replacing the oil pump,checking the cam sensors, and restricting the oil feed line going to the turbo since it is acting as a bypass valve decreasing pressure. I also wanted to check pressure going to the solenoid itself but can not find the proper fitting to connect a pressure gauge.Thanks

 

did u try getting a new silinoid...

 

60psi at WOT is real close to the minimum pressure required for VTEC operation. You mentioned in another post you have a oil light coming on at idle at times, which would mean you have exceptionally low oil pressure at idle (less than 4psi)

I'd be suspicious of some worn or out of range bottom end clearances causing the low pressure.

 

Check you oil level and spark plugs. Low oil level and bad spark plugs will cause the VTEC not to engage.

 

As pointed out.. check the oil pressure first. Then check your Vtec Solenoid, check your vtec engagement point on EMS is set correctly, and if all fails, check your rocker arm assembly to make sure you didn't loose any of the vtec rocker arm pins (the pin that connects the moves in and out of the arms to engage vtec)

 

Ill check the oil pump, bottom end and the pins. I PMed Slows to ask for some advice and what areas might be an answer on the bottom end...

 

If you're lacking oil pressure on the pump side you can always shim the pump to produce whatever oil pressure that you may need.