Took my car in over the weekend to get smogged. When I got to the place I forgot to close my hood all the way cause I put my stock back on the night before, so I tell the guy why my hood was opened. He took my car and came back 15mins later, telling me my car failed. He said that it probably failed cause I put my stock intake on and didn't drive it enough to have the computer learn. Forgot which measure I failed but I know max was 45 and at 25mph I was at. 75. So he told me to drive it around awhile , so I drove it the next day for a few hours, and took it back a day later and now it passes with a 4 with a max of 45. Does this sound shady? Does the car really need time to learn with something is done to the car?????

 

you modified the intake without a tune for it, so the ecu needs to adjust fueling and maf scaling in order to reach a target air fuel ratios. this can take a couple days. when you put the stock intake back on your car was running richer because the ecu learned that the previous intake flowed more and needed more fuel as well. now you put "less air" intake on and the ecu is throwing the same amount of fuel, therefore rich afr's.

the ecu had to learn to accommodate the more air in with more fuel(to prevent leaning out and detonation), so putting the stock one back on caused a rich condition, so the long term fuel trims had to be adjusted by the ecu which takes time.

 

Thanks for the help bmx. I didn't know the ecu needed to relearn everything.