Vibrant Headers CEL and fuel efficiency issue

[Adamo23]

i was just wondering if anyone else has had problems with vibrant headers throwing a P0421 code. "Warm up catalyst efficiency below threshold (Bank 1)"

the CEL comes on and off occasionally, and also my fuel efficiency isnt the greatest. for example i drove roughly 90kms from my cottage to my house 90% highway and it used about a quarter tank which i dont think is that good. its weird because only sometimes my car uses alot of fuel and sometimes it seems normal. im running a hks exhaust aswell which means the car is running catless and i notice a strong smell of like unburnt fuel when i come to a stop after driving, i was told that my car is "running rich". so i was wondering if theres a solution to any of this or if anyone has or has experienced similar problems/issues. any help is appreciated. thanks

[silverstarmazda]

lol drive harder and heat that cat up. the computer is getting a cold signal and might be richening the fuel/air mixture. hence your bad fuel economy. not related but kind of is.... my thermostat was stuck open before i replaced it, and i would get crap fuel economy since the engine doesnt warm up until i actually get to my destination... not sure but i would check with other forum members about this. you should also be running at least one cat, for the sake of the environment man....we dont need to be breathing all that crap. maybe because you have so much flow, the sensor isnt warming up?? i havnt gotten into the exhaust mods yet so get another opinion too

[Thrizzl3]

i was just wondering if anyone else has had problems with vibrant headers throwing a P0421 code. "Warm up catalyst efficiency below threshold (Bank 1)"

the CEL comes on and off occasionally, and also my fuel efficiency isnt the greatest. for example i drove roughly 90kms from my cottage to my house 90% highway and it used about a quarter tank which i dont think is that good. its weird because only sometimes my car uses alot of fuel and sometimes it seems normal. im running a hks exhaust aswell which means the car is running catless and i notice a strong smell of like unburnt fuel when i come to a stop after driving, i was told that my car is "running rich". so i was wondering if theres a solution to any of this or if anyone has or has experienced similar problems/issues. any help is appreciated. thanks

does the header have a high flow cat on it? The HKS exhaust only has a resonator and a muffler btw lol.

I/H/E combos allow the engine to breathe more therefore increasing fuel consumption. As for the running rich situation you may have a faulty O2 sensor. Take it to Jimmy and see what he says.

[lcianf01]

My 05 2.0 on a qyarter tank on full high 140-160km

[thanu31]

lol when i had header and exhaust i ran catless....all you could smell was fuel..
i was running very rich, which also let me shoot some fire

have fun with it! :p forget fuel consumption