Is there harm in running with a CEL?

[mikeSS]

Originally Posted by Bell040

and if you break a valvespring, blow a gasket, a sensor dies, etc. ... you wont know because you have learned to live with the lighted CEL.

i was just about to say this, having a CEL pop on here and there is a problem.

the dealership is going to say, the car a check engine light was on for a while, why haven't you brought it in?

i am pretty sure they can also tell if a code poped up? even if you clear it ?

[justa25thTA]

Originally Posted by Juiced1

Not sure how they do TX inspections but I would assume no. Don't forget a CEL can be easily deleted. All you need to do is take it to your common auto parts store ane delete it. Or buy a cheap obd2 scanner and you can delete it yourself. You can find them for $20-25 and keep it in your glove box if you like.

I think that just clearing the code won't work. I was getting my truck inspected and the lady if front of my had a Mercedes that wouldn't pass, all of the sensors were not reporting that they were ready. Turns out she had a check engine light on and had her neighbor clear it. Apparently it takes some time for everything to report back ready.

[hunter1660]

I'd get a muffler delete... it sounds great and won't Void the warranty... looking at the dinos a tune is not worth losing the warranty over... If I was going to void my warranty it would be. For more HP than headers and a tune will produce IMO

[navyblueburnout]

Originally Posted by jrhaus76

People who do this are just plain silly.

I call them cake and eat it too-ers. They want to mod the car to their liking bc they aren't happy with how GM built it BUT still expect GM to cover it. If you're going to mod, face the facts that your warranty MAY be voided. Don't half ass it. If you're that stuck on your warranty, don't turn a bolt on you're car. Problem solved.

^ I agree. I made that decision before I even bought mine. The decision was *#$! the warranty im modding my car!

[Fraxum]

Originally Posted by MarylandSpeed

I have had the opposite where it runs a little rich. Either way..nothing that will damage the engine. I would say check the codes every once in a while though as ones not related to the cats may reflect another issue.

+1 I have the LT no tune setup. Buy yourself a code reader and check the codes every once in a while. Turn them off if you like. I can run for weeks with no codes. It must relate to the type of driving I am doing.

I am thinking if i wind out the lower gears at anything less than full throttle a code pops up. I am not really sure.

But no big deal really. I am looking forward to eventually getting a tune. Nice to know there is more left in the car.

One thing you can do to minimize the codes is install rear O2 spacers. I have these but since my cats are extra long they do not seem to be completely effective.

Some recommend putting washers in these to reduce the gas exposure to the sensor. I did not do this.

[Fraxum]

Originally Posted by 96/10SS

Yea I just am really hesitant about it, i might just wait until i find a mod friendly dealer or not worry about the warranty. Im not worried about leaving power on the table this car is plenty powerful enough as is i just think the tone these cars get with headers is amazing plus a little extra hp never hurt any one.

The long tubes really wake the car up. My traction control light is now almost all the way through first gear.

[mikeSS]

Originally Posted by Fraxum

The long tubes really wake the car up. My traction control light is now almost all the way through first gear.

wait tell you tune

[MRGOODWRENCH3]

Originally Posted by MarylandSpeed

I ran mine for a year with the CEl with no issue. Running LT headers normally requires replacing the factory cats with high flow ones, and moving them further back. On each exhaust bank, you car ha stwo O2 sensors. One pre cat, and one post cat. The computer compares the readings from the sensor before the cat, with the readings from the ones after the cat and decides if your car is running right. Since you moved the cats, and changed how they flow, it is of course outside the readings your car expects. Basically, your car is saying "Hey the rear O2 sensor readings say the cats are failing"..but you know that is kind of a false positive.

Some people get the light immediatly, others it takes a while. The time where it is most likely to come on is after you start the car because the high flow cats do not light off and get to temp as fast. There is no brand that is better than the other at preventing a CEL.

This is all Wrong information. The post catalyst O2 sensors DO NOT have anything to with the calibration of the air fuel ratio for the engine to run. The Pre-Cat O2 sensor is what determines AFR. The Bank 2/ Post Cat O2 Sensors Only monitors if the Catalytic Converter is working. That is why the codes for post O2 are shut off in the tune when Long Tube headers are installed.
The computer only has so much capability to compensate for a lean or rich condition. You guys running long tubes without a tune, it's just a matter of time....

[MarylandSpeed]

The computer takes readings from the precat O2 and compares them with readings from the post cat O2 to see if cat is working fine. It is expecting a certain variance between the two...and anything outside that variance is taken by the computer to mean there is an issue with the cats..and throws the rear O2 codes. The whole AFR thing has nothing to do with the cat inefficiancy code being discussed.

I don't know who you are, and honestly I am not here to argue and throw face palms or emoticons at people. However I have personally run my car over a year with headers and no tune, and put it on the dyno several times. Every time the AFR was either just right, or slightly rich. Is buying headers and not tuning the car ideal? no...however there is no real danger to it either if you want to hold off getting a tune untill you have done more mods or whatever. No more danger than someone running say high flow cats without a tune, which happens all the time. Going from 4 factory cats to two high flow ones is the biggest flow change with headers..not so much the LT's themselves. Especially on a stock car.

Originally Posted by MRGOODWRENCH3

This is all Wrong information. The post catalyst O2 sensors DO NOT have anything to with the calibration of the air fuel ratio for the engine to run. The Pre-Cat O2 sensor is what determines AFR. The Bank 2/ Post Cat O2 Sensors Only monitors if the Catalytic Converter is working. That is why the codes for post O2 are shut off in the tune when Long Tube headers are installed.
The computer only has so much capability to compensate for a lean or rich condition. You guys running long tubes without a tune, it's just a matter of time....

[Juiced1]

Originally Posted by justa25thTA

I think that just clearing the code won't work. I was getting my truck inspected and the lady if front of my had a Mercedes that wouldn't pass, all of the sensors were not reporting that they were ready. Turns out she had a check engine light on and had her neighbor clear it. Apparently it takes some time for everything to report back ready.

You're supposed to give it a half hour or so of good driving. Let it go through a full heat cycle and then take it in. I've had a few personal cars that even with a tune would still throw a cel here and there. If I had a random code pop up before a test I'd delete it and take it the next day and had no issues. The car also had a large cam, long tubes and off road pipes. Passed everytime. Sounds like the Mercedes lady had her neighbor delete the cel and then drove it straight to the testing place.

[96/10SS]

Thanks for all the input guys, just something I have to think about

Originally Posted by hunter1660

I'd get a muffler delete... it sounds great and won't Void the warranty... looking at the dinos a tune is not worth losing the warranty over... If I was going to void my warranty it would be. For more HP than headers and a tune will produce IMO

Yea I was going to do a muffler delete but for a couple hundred more dollars I can get a full Pypes catback with x-pipe and I love the sound so if i dont do headers I am definitely getting the catback soon.

[BowlingSS]

If you get a CEL and just reset the code this will not let you pass emmisions. There are a number of tests that have to be ready. GM has a method/procedure of driving that will give the tests time to get ready after being reset but most of the time you can just drive around for a day or two.

My experience with headers is you will always run rich. Some cars run richer than others but all the ones I have messed with will run rich. A tune is really needed because it is not good to run rich for a long time IMO.

Bill

[Dion_1969]

Originally Posted by Fraxum

+1 I have the LT no tune setup. Buy yourself a code reader and check the codes every once in a while. Turn them off if you like. I can run for weeks with no codes. It must relate to the type of driving I am doing.

I am thinking if i wind out the lower gears at anything less than full throttle a code pops up. I am not really sure.

But no big deal really. I am looking forward to eventually getting a tune. Nice to know there is more left in the car.

One thing you can do to minimize the codes is install rear O2 spacers. I have these but since my cats are extra long they do not seem to be completely effective.

Some recommend putting washers in these to reduce the gas exposure to the sensor. I did not do this.

I don't think this works on the Camaro. I tried the same thing and kept getting codes.

[Dion_1969]

Originally Posted by MarylandSpeed

The computer takes readings from the precat O2 and compares them with readings from the post cat O2 to see if cat is working fine. It is expecting a certain variance between the two...and anything outside that variance is taken by the computer to mean there is an issue with the cats..and throws the rear O2 codes. The whole AFR thing has nothing to do with the cat inefficiancy code being discussed.

I don't know who you are, and honestly I am not here to argue and throw face palms or emoticons at people. However I have personally run my car over a year with headers and no tune, and put it on the dyno several times. Every time the AFR was either just right, or slightly rich. Is buying headers and not tuning the car ideal? no...however there is no real danger to it either if you want to hold off getting a tune untill you have done more mods or whatever. No more danger than someone running say high flow cats without a tune, which happens all the time. Going from 4 factory cats to two high flow ones is the biggest flow change with headers..not so much the LT's themselves. Especially on a stock car.

The ECM see's the reap O2 sensor reading and throws a bunch of fuel at the problem trying to heat the cats. This is why you run rich with the LT's. I know my exhaust tips are all carboned up from just a few hundred miles. My plugs are probably in similar shape.
No worries though- getting tuned on Friday!!!