i have a 98 honda civic sohc i am putting a custom turbo on. i was wondering what i have to do to the ecu so it will run right.

 

The cheapest way to make the ecu no throw a code is to get a missing link, or equivalent, so that the stock MAP sensor doesnt detect any boost. I guess at the bare minimum you would need just that and and something like a vortec FMU to supply the fuel.

 

Obd2 cars wont throw a check engine light until over 11psi.