I installed a HKS BOV on my 99 audi a4 quattro 1.8T. Now it surges at idle some times, it back fires occasionally, has slugish throttle response at lower rpms, and smells like its running rich? Did I do something wrong? I disconnected the diverter from the charge pipping and installed the nes HKS BOV on the charge pipe. I left the diverter still hooked up to the intake. Should I completely block it off? Do these cars not like aftermarket BOV installed?

 

Read the sticky posts in the FAQ up top - you should get a MAFless tune to run a blowoff to avoid rich spikes. And yes, if you don't cap it off completely you've created a vacuum leak which will screw up all sorts of stuff.

 

oh wow, thanks ill check the sticky