Originally Posted by atropos
This is exerpted (is that a word?) from NPOG:
"There has been much debate over how OBD2 ('96 and up Preludes) works and what it does. What is known to the tuning world from dyno plots and tuning is that the ECU on OBD2- equipped vehicles will eventually "detune" modifications that alter cam timing, ignition timing, and air/fuel delivery. This includes common breathing modifications (intake/header/exhaust and port work). What this means for the average tuner is that when you bolt on i/h/e, do manifold or head (port) work, change injectors or fuel pressure, or just about any other engine-related mod, the ECU will detect the change in emissions and alter the timing and fuel maps to compensate. This has been dyno proven on multiple occasions with multiple different performance mods. It also happens that this is especially true for air/fuel controllers (AFCs). "
What do you guys who have any engine mods done do as a workaround for this? The site lists several options, as cheap as pulling the fuse and letting the system reset every few days, up to suggesting something like an AEM ecu.
If you were to go the route of an aftermarket ecu, or even just a reprogrammed stock one, what happens when inspection season rolls around? (here in NY, the inspection station hooks the car up to a computer, etc etc...)
http://www.ntpog.org/mods/fifth-afc/ecu.shtml
this site will solve all your problems and any questions you may have had.
also it has other nifty how too's as well.