fahaoo

I installed my catback exhaust ( Invidia Q300) and ETS HFC about 4 days ago and I've been pullin it a lot these past couple of days maybe 7 times. and today just randomly driving my service engine soon light came out and it was 46 degrees outside. Is this normal cus i replaced the cat? or should i be worried?? I'm not tuned yet, i scheduled it in a month. So should i keep driving or no??

Omar Ramos

ok never ever drive a car without a tune after you install new parts, this is very dangerous to the car itself, and yes you should be worried, and to drive it that hard is a huge no no without a tune, i would seriously stop driving it in hopes that you didnt mess it up already,

DAN123AC

Switch it back to stock or get a tune asap. Like Omar Ramos said you need to get a tune. The HFC is allowing more air to move than the ECU can adjust. Your fuel and air ratio is out of whack most likely. If you have it I would hook up the tactrix cable and ECU flash and read the service code and see what it says.

nolimits1320

iTrader: (10)

I'd venture to say you threw a downstream o2 code from the HFC. I seriously doubt you caused any harm. Pull the code, go from there.

Iowa999

iTrader: (1)

I agree with the above and got a giggle from the Chicken Littles. There's a word for folks who stop driving their Evo every time it throws a code: passenger. And you don't need a Tactrix cable to read the base codes; any little OBD reader can do it.

wenbenten

iTrader: (1)

Drive it like a Lancer es until u get that TUNE!!!!!!!!!

JonGonzo

^^^ what no limits and Iowa said. I would just keep driving it and check the code to make sure it's nothing serious. If u installed an intake I would be more concerned but for a hfc and catback I wouldn't worry about it.

Kendogg

Changing to the ETS HFC is changing the test pipe correct? I thought you have to get a tune if you change the test pipe (to a wider one, HFC, straight pipe, etc)

ogarcEVO

iTrader: (1)

I also giggled at the "stop driving your car". It is probably a P0420 low catalyst efficiency code due to the HFC. When I put my test pipe, it didn't throw the code till several days after driving it. I also don't think a HFC will lean it out enough to cause any harm.

Iowa999

iTrader: (1)

There's a line between "have to" and ought to"; the mods in question don't usually cross it. To get the most from the mods, yes, a tune is in order, but assuming it's a minor code thrown by, e.g., low catalyst efficiency, it doesn't need to be done at once. Some reading and chatting to decide where to get said tune is the best use of time.

As to the code coming during a "pull": many codes are only triggered at high load and/or flow rates. That part of the story is not surprising at all. If, for example, you go WOT on the first cold day, you'll often throw a minor (and temporary) code as the long-term fuel trims don't move quickly enough. If you stop driving when this happens, the LTFTs won't adjust and you won't know that it wasn't a big deal.

littlezrexer

iTrader: (1)

I giggled at this^

Omar Ramos

you can laugh all you want at "stop driving your car"

some people dd these, if something horrible is wrong with his car and he keeps driving it he will be paying loads of money, let someone who gives zero ****s about their car drive it with codes popping up, so why take that 1 chance if it being something actually serious over its probably nothing?

just saying bro im almost positive most people rather be on the safe side

DAN123AC

I love how people keep saying oh no worries keep driving. Funny thing is any PROFESSIONAL TUNER who has been doing vehicle work for years is going to tell you to tune the car no matter what the part is. Why would you risk a car worth thousands of dollars for a part that cost a few hundred . I don't get the mindset behind this. People are always looking for a cheap way out to not get a tune. All cars are different even if you have the same model year etc. They all act different. Perfect example is when I changed my intercooler it threw my AFR off by 4.0 which is a ton. What works on one persons car does not mean it will work on another and be ok. Tuning not only ensures performance but it ensures a proper safety measure to make sure that part is working in unity with your car. PERIOD

Kreeker

iTrader: (10)

I'm not saying you're wrong, but don't you think there is a conflict of interest when you write "any PROFESSIONAL TUNER who has been doing vehicle work for years is going to tell you to tune the car no matter what the part is"? This is how they make their money, of course they want you to tune it after each part install.

nolimits1320

iTrader: (10)

Well, let's see what the exhaust will do. The increased exhaust flow can raise the boost slightly. If you're running stock, then there is plenty of margin for this. The ECM sees this flow and compensates fuel appropriately. It will just give you the feel of increased performance that will be credited to the exhaust. The HFC will flow more, giving the secondary o2 above average readings, making it think the catalyst is below threshold....which will throw a code. That's really all there is to it.