Honda Accords are manufactured not to perform up to their potential. They are made to conform to a series of state and federal laws governing street performance, miles per gallon and emissions. The electronic control unit (ECU) is a computer inside the Accord that controls the performance of the engine. What regulates the top speed of an Accord is not a physical component, but rather it is program written into the ECU that adheres to the laws. Remove the ECU and take it to a professional to be rewritten in order to remove the speed governor.
Open the hood and remove the negative battery cable using an adjustable wrench.
Expose the ECU. Find where the carpet of the front passenger side meets the firewall and pull the carpet toward the rear of the vehicle with your fingers. Remove the lower dashboard plastic kick panel by unfastening its clips with your fingers.
Identify the ECU as the larger of the two black boxes. Remove the metal belt holding the ECU in place by using a socket wrench to unfasten its two retaining bolts. Pull the ECU away from the firewall and unplug the wiring harnesses connecting it to the vehicle with your fingers.
Take the ECU to a professional for the program to be rewritten for maximum speed. Plug the wiring harnesses back into the ECU with your fingers. Install the reprogrammed ECU into its terminal, lay the metal belt back over the ECU and secure the belt by fastening the two retaining bolts with the appropriate socket wrench.
Clip the kick panel back into place and roll the carpet back to the firewall. Reconnect the negative battery terminal with an adjustable wrench, and close the hood.
