Ok, before I get slammed with all the common symtoms to check, I have been searching for a few days trying to solve this problem.

1994 D16z6 Civic SI, vtec no longer kicking in after headgasket changed.

WHat I have done,

Changed oil, Oil level is fine. Tested Solenoid on another car, works fine, on my car it doesn't. Checked wiring, checked grounds, engine is at operating temp, no check engine light or any codes.

My Vtec worked fine before head gasket change.. Few hours later after install complete, no Vtec.

After searching and searching, I can not find a straight answer to my issue. My question is, does this engine require a particular head gasket. Could this be my issue?

 

If the wrong head gasket is in there, it could be blocking the hole where the oil is fed through that goes to the Vtec solenoid. Because if it's not reading any oil pressure, it's not going to work, just like if you are down about 1L of oil, Vtec will not work then.

 

^+1. Also, check your fuses.