okay i just put a d16z6 into my cx civic. got a p28, vtec subharness, hook everything up, besides bad O2 sensor cars great. after maybe a day, code 21 for vtec sol. check the harness to make sure it's tight, clear the memory, codes gone. but it keeps coming back, after maybe a day or so. i decide to change the whole vtec solenoid and see if it's just bad. goes fine for a day, then code comes up again. lately it's been so bad that when i remove the backup fuse to clear the memory, it STILL pops back up afterwords with out even driving the car first. Like i said ive replaced the solenoid, i checked all the wiring, everything seems 100% fine. what else could it be!? bad ECU? guy claims he NEVER had any problems with it. i really dont want to spend the money on another ECU to try and find out it's not the problem. SOME HELP PLEASE!
by the way, vtec does engage when the code isnt up, then wont untill code gets cleared

 

sounds like its the ecu, not 100% sure tho

 

also one strange side not, the vtec subharness (hasport) is made for a knock sensor as well, not thinking i did wire it into the ecu harness, and at the motor it's just laying there unused, would that make any strange problems? When it comes to electrical **** im dumb!

 

o, that is probably the problem, i had that problem too my ecu error code for knock sensor kept comming up which was not wired right, same issue when i drove it a little hard the code would come back, u could've used ur stock harness and just added for vtec and oil

 

yeah it is kinda when i drive it harder that it happens, im going to unpin the knock sensor and see if that helps it. I would have just wired it myself, but my buddy had the hasport harness and gave it to me because he didnt need it. so i used it...looks clean.