Well, on my H22A the Vtec stopped engaging a while back. I knew the car was due for an oil change and the Vtec came back again after the change.

Now, it does it again. I didn't do much miles with the car (like 3k miles). I guess that changing the oil again would solve the problem again.

However, isn't this odd a bit? I mean I know people that wait alot more between their oil changes and don't have any problem. I'm uting Motul 8100 which is a good oil.

The engine had a bit of sludge in it when I bought the car because it has been running in limp mode for like a year and running rich. I used some Motul Engine clean and wiped all that I could see on the cams/rockers when I did the timing belt.

Could sludge build up in the Vtec Pressure Switch and prevent Vtec from engaging? I don't have any CEL codes or anything. The ECU is just NOT engaging the Vtec solenoid since it cuts at around 6500 rpm.

Before I invest in an oil pressure gauge, do you guys have any thoughts on this?

 

check the solenoid gasket and oil level

 

https://honda-tech.com/zerothread?id=1812135