Hi guys: My friend is got a 1989 Prelude and he went to DEQ yesterday to have it's emission checked. But it turned out there is something wrong with the air injection system. I've no idea how to help him since I'm not familiar with any air injection system. What do you guys think? Should he change his oxygen sensor and how should I help him out?

 

For extra information, he actually failed the DEQ emission test, so he won't be able to drive the car until he passed the damn test!! Poor Guy