New Headers= Dreaded CEL
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,090
Likes: 51
From: Georgetown TX
New Headers= Dreaded CEL
Installed new Melrose headers w/RT hi flo cats 3 wks ago... Until 2 days ago everything was great then suddenly the dreaded CEL appears.
Code reading is P0420 (catylst efficiency) Bank 1. After telecon w/ Melrose and R/T they are sending a new modified wiring harness...hope this works. From reading this forum, this seems to be a common occurence. What have you guys done to correct this? Is a tune necessary?
Code reading is P0420 (catylst efficiency) Bank 1. After telecon w/ Melrose and R/T they are sending a new modified wiring harness...hope this works. From reading this forum, this seems to be a common occurence. What have you guys done to correct this? Is a tune necessary?
Pro
Joined: Jun 2005
Posts: 730
Likes: 0
From: Winter Springs FL
Installed new Melrose headers w/RT hi flo cats 3 wks ago... Until 2 days ago everything was great then suddenly the dreaded CEL appears.
Code reading is P0420 (catylst efficiency) Bank 1. After telecon w/ Melrose and R/T they are sending a new modified wiring harness...hope this works. From reading this forum, this seems to be a common occurence. What have you guys done to correct this? Is a tune necessary?
Code reading is P0420 (catylst efficiency) Bank 1. After telecon w/ Melrose and R/T they are sending a new modified wiring harness...hope this works. From reading this forum, this seems to be a common occurence. What have you guys done to correct this? Is a tune necessary?
Le Mans Master
Joined: Oct 2006
Posts: 5,474
Likes: 3
From: Bradenton, FL & Chandler AZ
St. Jude Donor '09
I have the same code. I'm not too concern because this code does not put car on limp mode. Anyway, I just received a pair of o2 "clamps" which bolt right on and are suppose to resolve the issue 95% of the time. They were recommended by another CF member. They are not sponsors so PM for their name. The cost was around $30.00. I will be installing them sometime soon.
Tech Contributor
Joined: Jul 2002
Posts: 14,949
Likes: 263
From: St. Louis, MO
St. Jude Donor '08
Either 1. get a tune, 2. pay someone with HP Tuners $200 (cost of a Tuners license for your car) to turn off the codes with HP Tuners, or 3. sping for the $500 and buy your own copy of HP Tuners and learn it from their forum and other forums. If you go this route you can split the cost with a buddy and tune his or her LS2 car as well. Or 2 buddies with LS1 cars, they cost $100 to tune each.
I recommend getting the full tune. Go to the Southeast Section or maybe search here, Mike Norris has been running specials on his tunes and you'll get a lot more than just your codes turned off with a full tune. A tune does a lot for an LS2.
I recommend getting the full tune. Go to the Southeast Section or maybe search here, Mike Norris has been running specials on his tunes and you'll get a lot more than just your codes turned off with a full tune. A tune does a lot for an LS2.
Last edited by Joe_G; Jan 15, 2007 at 05:09 AM.
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Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
The car is running lean at idle and rich at WOT. This heats (in closed lopp due to too little fuel) and cools the cats too much (more fuel dumped at WOT due to measured lean condition at closed loop)inefficiently. The car is running as it should given the untuned nature of its fueling changes forced in by the headers. Once tuned, (wthout deleting codes) it wont happen anymore. The CEL is a normal response to an untuned bolt on mod and once you tune it properly it will run properly. No band-aid fixes are necessary.
The car is able to compensate for up to +24%/-20%. That is why some cars throw a CEL and some don't. It doesnt mean that any untuned car with headers is optimum.
The car is able to compensate for up to +24%/-20%. That is why some cars throw a CEL and some don't. It doesnt mean that any untuned car with headers is optimum.
