jermstyle

I’m about to remove my KooKs catted Y and install a KooKs ORY.

When the cats are removed and it raises the no cats code, will this diminish performance any or just be an annoyance because of the CEL?

SLPCAMAROSS

As far as i know its just an annoying code to alert you that theres something missing. It shoulden't cause any performance issue's at all. You can get 02 Sims to correct it and make the computer "think" you have cats on when you really dont. I might be selling my sims .. let me know if your interested.

jermstyle

So it won’t cause the computer to lean out any due to the excess fuel hitting the O2's? Just want to make sure because I've got a decent shot of nitrous on this car and the tune needs to be right.

LS1LT1

iTrader: (16)

Well you could have a lean or rich condition from running no cats without a tune that could be detrimental but no, the light alone will not cause that just from being on.

Dal1as

If you have an SES light (any SES light) you are running in limp mode which causes the car to dump extra fuel, putting you in a rich condition. This will effect performance. Get the code deleted with LS-1 edit or something.

jermstyle

Okay, thank you... That's what I was looking for.

Now for one more, lets say I remove the codes and get rid of the SES light, will no cats cause the engine to run lean or should be about the same?

LS1FIRE

iTrader: (1)

I have the ses light on from not having cats . I had o2 sims but they went bad. I didnt feel any power loss. It didnt feel like it was in limp mode. And everything seems ok. I am not sure if it hurts the performance i didnt feel any loss tho Can someone clarify this?

jermstyle

Well I have a code on now from removing my AIR system and the car still puts down massive amounts of power and runs great, but it could have something to do with the car running a little rich though.

I really don’t care about the code, I’m going to have all of them removed with LS1 edit this weekend, I just need to make sure that no cats wont cause the engine to lean out because I’m running nitrous and I kind of like my car.

Ryan02SS

iTrader: (3)

LIMP MODE????? LOL There is no loss of performance associated with the SES light from removing the rear cats on the LS1! The light is simply letting you know you have a malfunctioing cat or the cat is not there. The PCM will test for the cats every certain amount of time an only at certain speeds. This explains why people that swap to longtubes @ ORY and don't immediately get an SES light yell for victory. Then when they take a short highway trip at speeds over 55mph it suddenly comes on. I can assure you as the sun will rise tomorrow that there is no performance loss with the SES light on for this certain code.

LS1LT1

iTrader: (16)

Based on that logic will simply pulling out the bulb for the SES light change one's A/F ratios as well?
I don't think simply having the light on will affect anything ALL BY ITSELF, it's only what CAUSED the light to go off (ie: LTs/ORY/bad cats/bad O2s etc.) that potentially can, in most people's opinions anyway.

Dal1as

Based on what logic? What does the bulb have to do with the computer? If an SES light is set,the computer automatically goes into what's called limp mode and richens up the A/F ratio decreasing performance and eating gas. The fact the light is on has nothing to do with it. It's why the computer set the light off. This is not opinion but fact. Now maybe the PCM is smart enough not to do this if the SES is for a loose gas cap, I don't know.

Dal1as

Assure all you want but you're wrong. I know all about the OBD2 tests. If they fail car goes into limp mode. Simple as that. The 55 mph test is one lots of O2's (with LT's) fail. In fact certain header companies are working on this as we type.

NicD

iTrader: (7)

This is simply incorrect. There are codes that affect the fueling/spark/performance and there are codes that do not. The rear O2 codes DO NOT affect anything.

LS1LT1

iTrader: (16)

While I have challenged you on this I do have to admit that it makes sense and it's not the first time I've heard of it but, when I hear the phrase "limp home mode" I think of reduced power, sputtering, a generally BAD running car.
So how is it that so many people have run amazingly well with all sorts of dash lights lit up on their cars? I have a friend who ran in the 11.7s at over 118mph in a 6 speed bolt on car with the SES light having been on for 8 months. Now maybe he was killing his O2s (no cats) all the while, maybe he was even hurting his rings but his car ran like a champ.
Not disagreeing with you, just trying to understand exactly what and how bad 'limp home mode' really is.

'Trust'

iTrader: (24)

The car will only go in to loop when the FRONT o2's are messed with, the rear o2's can screw up as much as they want but they will ONLY set of a light, nothing more

calongo_SS

iTrader: (7)

rear o2's will not affect performace. front's now that's a different story.

Dal1as

Yep. Looks like I was wrong. I knew the front O2's did and figured the rears would do the same. My bad.