Hi !

Our Del Sol has a problem.

The VTEC doesn't disengage as it should below 5000 rpm as it's configured to do so in the ECU. (Aem v2)

There's no problem with the settings.
The engine is a B16A2 in a Del Sol.

As far as I could find out, the problem is (if it is), the oil pressure is still above 70 psi although it's around 3000 rpm. When the car returns to 1500-2000 rpms, VTEC disengages as pressure drops below 40 psi.

Can this be a problem ? if it is, why ?

Thanks

 

If VTEC does not disable it is due to oil pressure leakage in the VTEC solenoid allowing the system to remain engaged. If you have an aftermakret system to control VTEC (which is kinda dumb), disable it. and recheck.
If you still have problems you have an internal oil leak to the rocker shafts, leading to your problem. This can be caused by:

1: Short to ground in the VTEC solenoid circuit. (PCM will see this during startup)
2: Excessive oil leakage past the VTEC solenoid spool valve, engaging the system when it shouldn't be. (IE stuck spool valve allowing leakage)
3: Excessive oil pressure, which can exacerbate an internal oil leakage problem.

Excess oil pressure is a serious problem as it will ruin your oil pump gears. In a typical B16/18 I see will have around 12-15psi at idle, and 55ish at VTEC. Near redline the oil pump relief will open up and maintain around 75ish psi.

Inform us of any modifications to the oil system, including turbo oil feed if you have one.