I recently installed a cat-back system on my LLY......plan to install the frontpipe and eliminate the cat, but haven't put it on yet. I was told the LLY is programmed for backpressure from the cat, and removing it can cause a shift to limp mode. Has anyone experienced this, and how common is it?

You "might" throw a code. I didn't. It won't make you limp (your wife should be happy about that).


Nobody is sure why "dead kitty" mods cause the EGR codes, but apparently it does happen to some trucks.

Since you likely don't have the CA, or the NE emissions package your check engine light won't even come on.


I've been running Kitty Free for about 10,000 miles and have never had any problems at all.


My Cat pipe is on hand for those pesky emissions tests though.

so will a ne truck set a coad with out a muffler or cat? i am wondering because when i get my tts will that take care of it?


not to steal this guys thread but when i get my tts and duel exhaust i want to get ride of the cat and muffler untill emissions. so if i do get the tts will i through any codes?

LLYDMAX - I like your answer. This is a Utah truck. I've heard about code problems, but the limp mode thing was something new. Changing exhaust isn't much fun and I don't want to have to do it twice. I'm also in the SL area....ATS installed your exhaust? You mention a removable cat. I'd been thinking about that too. Is it just cat-long section of pipe, or does it include the cat and all the way back to the square flange?

yamahagrizzly,



If it is a Federal Emissions truck, then the exhaust will likely set a
code, but not turn on the SES or CEL, whatever you want to call
it. The TTS will likely not set a code.



Dennis

Mt Hunter,


The ATS "Test pipe" goes from the down pipe to the square flange. However the flange is now part of the Cat pipe section, and the test pipe and cat pipe connect to the cat back section using a slip fit and a large band clamp. Really easy to use, and no leaks.


You are welcome to check it out in person. Just send me a PM.


Just to be clear, Baimpala is correct. Removing the cat will set an internal code. It just won't set a light on the dash.


There have been no negative effects on my truck by removing the cat OR disconnecting the EGR, And the service dept. at my dealer couldn't care less about either mod.http://www.dieselplace.com/forum/smileys/smiley4.gif


It's a win win situation. Less soot in the intake and lower EGTs on the exhaust.http://www.dieselplace.com/forum/smileys/smiley4.gif