Exhaust Related OBDII Codes

[chrisdemara]

ok so i got a header and catback off ebay it was bbp when i first hooked it up it worked amazing untill i blew my header ( lasted about a day)........so my car ran like shit. i got a new header that was a lot nicer and didnt make any big of a differnce.... so i hooked up an obd2 reader to it and got codes 401 which is egr insufficient flow i read some places that it could really effect you how can i fix this?
next problem is the obd2 also read code 420 which is catalyst system efficiency is below threshold bank 1 could this be because i put a new exaust with a high flow cat? or is there a bigger problem please help.!!!

 

[david-b]

High flow cat like test pipe, or still an actual cat? If it's a test pipe, the you may get the 420 code.

As for the EGR, make sure you have all the lines connected properly. You may also want to pull off the EGR valve and clean it out. Get all the gunk out and make sure it's working properly. It would mostly just cause bad idle, but may hurt fuel economy.

 

[chrisdemara]

i am going to test it tomorrow when i have off, i also was reading in the book that if the valve is not working properly that it can cause a vacume leak which will cause poor performance ...and as for the cat its is a cat but its not a street legal one i wouldnt even call it a cat. and thanks very much for your reply i will repost after i test