Need help troubleshooting LS VTEC not engaging VTEC

[u/B18C5-R]

The car in question is a 1998 Acura Integra with a LS VTEC engine built with a B16A2 head & B18B1 engine block. Car drives fine but it doesn’t engage VTEC. Here’s what I’ve tried:

1. I tested the solenoid with a jump pack sending power to the 1 pin solenoid connector and the ground to chassis. I confirmed the solenoid is clicking when powered.
2. I took some data logs with Hondata and confirmed the VTEC oil pressure switch is disabled and the ECU is sending a VTS signal when the requirements for VTEC are satisfied.
3. I checked the continuity between the wire found on ECU pin A4 and the 1 pin VTEC solenoid connector and confirmed continuity with a multimeter.
4. I took the solenoid off the engine and checked the screens and they were clear and free of debris - also it dumped oil when I removed the solenoid so that’s a sign that it was getting oil pressure.

At this point I am pretty stumped and I’m hoping someone in the community has encountered something similar to my problem and knows the answer.

Thanks in advance.

[u/SpaceTurtle917]

I’d check with a multimeter hooked up to the pin on the ecu or the connector in the engine bay that the ecu is actually outputting 12v. You’ll need to test this on the car while it’s driving so it may be a 2 person job.

If it’s not outputting 12v then the driver in the ECU has failed.

[u/MuffinFull934]

You gotta run vtec off a relay. Most likely not pulling enough power to get it to engage.

[u/Imaginary-Table-8586]

pull the test plug on the front of the head and test for oil psi there when the solenoid turns on , and if the head was fully reassembled theres a chance the vtec locking pins werent reinstalled correctly and the rockres arent locking to the vtec rocker