new headers and cats, check engine light
Thread Starter
Instructor
Joined: Dec 2004
Posts: 244
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From: nc
new headers and cats, check engine light
aight so i installed some kooks long tube headers and high flow cats, well everything was fine until the other day i get a check engine light, i check the code and it says TWC system low efficiency bank 1. can someone tell me why it would be having an issue ?
Burning Brakes
Joined: Oct 2001
Posts: 1,116
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From: Alhambra Calismognazifornia, in the country everyone comes just to complain but won't go back home!
some headers and hi-flow cats or even just hi-flow cats alone (my situation) can trigger this code. the increased flow throws off the readings from 02 sensors. has to do with the way the sensors work...the system is differential, it compares the reading from the second set to the reading of the first set and uses that data to work it's "magic". apparently, the increased flow decreases the delta (difference) too much and triggers the code. you have 3 options: ignore (that's sort of what i do, i reset it with my predator and move on), remove rear 02s and use sims, or have it tuned. i'll be getting headers installed soon and i'll be switching from solution 1 to 3. 
