Ok I just swapped a D16Y8 in my 92 DX...I am using all OBD1 stuff..P28 ECU...Well I wired VTEC up to the car like A4 for solenoid and D6 for Pressure switch which I grounded on the vtec solenoid..Anyways my car throws the Code 21 which to my recollection is the VTEC Solenoid or something to that affect..Well My car still hits Vtec and runs well...I have tried 2 ECU's both throw the same Code..21..Yes I did clear the ECU after changing them out and all..I am not sure if this is the only 2 wires I will have to run and if there is more which ones are needed I dont have? I am not using a Knock sensor so that is out of the ?..Has anyone had this problem? VTEC works but is throwing a 21 ECU code? Let me know what you guys think...Thanks for all the help.Honda-tech has got 2 of my swaps running.

 

Iam having the same problem but w/a b16a and a pr3 ecu getting code 21 but i cant tel if the vtec is kicking in or not

 

do a search on how to test vtec silinoid and do what it says.

 

21 is the solenoid. You need to have it going to A4, and it does not need to be grounded, if that is what you are saying! Also make sure you have it in the right "A4"! If you are looking at the "A" plug from the back where the wires are coming out, "A4" is the second plug on the bottom left!