I own a '94 civic coupe EX. I have a '01 GSR motor. When i put the motor in, there was some wires that i needed to tap to the ecu. I never had the time to do it. I was running on my P28 (civic ex) ecu and now upgraded it to a P72 (stock). It felt stronger... but when i punched it... the needle bounced back and 7,000 RPM. I was furious and demanded a refund. My friend came over and put the ECU into his civic.. (identical.. and with a stock single cam) and he revved up to 8,000 RPM. I was real confused. How come i can't rev up to 8,000 like i should? My friend said something is wrong with my wires because it's not the ecu. I thought for sure that he switched the chip inside the P72 to a P28 but he revved it in front of me all the way to 8,000. Could you help clarify why isnt my car revving up to 8,000. He also said that since my secondary butterfly and knock sensor isnt hooked up... that may cause it to red line early. Another thing that puzzles me is that when i put in my friends P72 ECU that is chipped... it revs up to 8,000 but there is a check engine light after you go past 50 MPH. But with the ECU that i bought, there is no check engine what so ever. I thought since my secondary butterfly and knock sensor isnt hooked up.. shouldnt there be a check engine light? (secondary butterfly and knock sensor are hooked up to the engine harness... just not tapped into the ECU). I was deeply appreciate if you could shine any light to my question. This puzzled me and my friends... thank you for your time. If you can provide more info.. could you please email me at LittleG112@hotmail.com. Thanks!