newbie here

(just bought a preowned 1999 Honda civic Si)

i just recently had the engine rebuilt, and the mechanic brought to my attention that my Si also has an unknown aftermarket ECU. he said the ECU is labeled not to be used in California, and it will fail smog.

anyone have an idea what kind of ECU it is?

i dont want to fail smog, so im looking around for a stock ECU to swap.


since im planning to do this, will there be a huge downgrade difference in performance?

 

it might be a chipped ecu