Got us stumped, no VTEC. Help!

Just swapped an h23a1 for the jdm h22 in my 94 Prelude Si. whenever i use the JDM p13 my car will run fine for a few, VTEC and all, then throw a code 23, knock sensor, and go into what i believe is LIMP mode. My rpm's are limited to 3000 when this happens. If say i drive in limp sometimes the CEL goes out and full power/VTEC etc comes back. Then it'll come on again. WTF could this be? A bad ECU? When i use the p14 ECU the car runs fine just no VTEC. Does the h23 have a KS? me and my mechanic that installed the engine are lost. Any suggestions?? Thanks for any help fellas.

You probably did this already, but have you checked all your connections, including grounds? Did the new engine run fine before.....if you did hear it that is?

I have checked all grounds/splices etc. they all seem fine. I didnt get to listen or see the engine before being bought. Got it from hmotorsonline. Let me say that they did me right. the engine is in immaculate condition, ns. From the way the car runs it seems to be in tip top shape. even when i did have vtec for a few, it was badass. This compared to my old h23 that got yanked. Is there a way to short out the ks. kinda like how i have to do when i pull ECU CEL codes. Does the h23 have a ks. i ask because i am using the h23 harness w/ a p13 ecu. we had to wire VTEC,Oil Pressure, and ground. I appreciate your help.

The problem is fixed. Used a new ecu that i just got and it throws no codes and VTEC works fine. Been running STP Fuel System Cleaner in it 4 times this week with every 15$ i put in at the pump (Shell 93). Maybe the car just needed a good Cleaning? Again thanks for all the help.

The problem is fixed. Used a new ecu that i just got and it throws no codes and VTEC works fine. Been running STP Fuel System Cleaner in it 4 times this week with every 15$ i put in at the pump (Shell 93). Maybe the car just needed a good Cleaning? Again thanks for all the help.

Eve though I didn't really help, I'm glad you got it running well, and thanks for the follow-up. Good luck with the engine in the future.

What ECU did you swap into it? Another P13?