Brilliant09GT

Hey all I have a slight problem. Nothin too big. A couple weeks ago I installed MAC Long Tubes, MAC O/R X Pipe, C&L CAI, and Brenspeed 93 Oct Tune (SCT X3) all at once. Talk about a PITA install. Long too. lol.

Anyway, car runs awesome. I love every bit of it. Well almost. A couple days ago the CEL came on. I used the X3 to read the code and it was (I believe, its been a bit and im too lazy to go check again) P0153. O2 sensor problems. I have the car out in the garage right now cooling down. I was wondering what could cause this? We only used one of the o2 extensions when installing the headers because the other o2 sensor didnt need an extension. The code didnt come on for a week or two.

Also there is a rattle now at around 1k when you first turn it on and its warming up. And at very slight throttle it rattles. Im hoping its just a loose bolt somewhere upstream that I can tighten and be done with it.

Are the headers supposed to Hiss? I love the sound, just wanting to make sure I didnt do anything wrong. I still have the stock mufflers on and before (stock setup) you couldnt hear the headers, just the mufflers, but as soon as I slapped these LT's on I can hear them hissing when I am giving it throttle.

Thanks for any help!

harraid5711

for the code, check the wires coming from your O2 sensors. if the wires rested against the headers, it may have burned them.

for the rattle, it could be a lot, but check the heat shields throughout your entire system. with the longtubes, it may have changed the orientation of the exhaust, and they may be hitting a heat shield.

for the hissing, i don't have longtubes, but when i added my o/r h i developed a bit of a hiss. i've heard that once you go o/r, it just allows you to hear the engine breathing more under your feet. however, i'd do the soapy water check, to make sure there are no leaks.....

Derf00

The ECM/PCM on these cars are very sensitive it's possible the extension is giving just enough resistance (by the added wire length) to the O2 reading to cause it to be off which codes the OBDII system. Try putting the extension onto the other side (so both sides have extensions), clearing the code and see if it comes back.

Brilliant09GT

Well I was just under the car and all the bolts that connect the LTs to the enxtender pipe before the X pipe were loose. Only a turn or two but im hoping thats what caused the rattle. Also, the passenger side aftercat o2 sensor is up against the heatshield so that might be causing a little rattle. I checked the o2 sensors and they are all tight and I checked the wires and it doesnt look like any of them are melted. Im thinking that the CEL came on just because of the extension. The CEL refers to a DELAYED o2 response so the extra line might have caused that. Im going to clear it and see what happens. Ill lower it and start it up to see if the rattle is gone. Other then those bolts and the o2 sensor being up against some of the heating aluminum stuff I cant think of anything else that would cause a rattle.

aircare84

I get the P0153 about every 2 weeks or so. My LT's have the O2 sensors down in the collector. Had to use both O2 extenders.

I had Brent(Brenspeed) do a custom tune on mine in Feb. & talked with him about the code; he said it was due to the location of the repositioned O2 sensor, it actually runs cooler than the stock location. I had him dial in some delay on the circuit for me , but didn't eliminate the issue. It's just an annoyance for me & I'll just clear it when it comes up. I've had Brent try a few tweaks & still have the same.
No performance issues, but I have found out if I let the car warm up for a few minutes before driving, it won't throw the code near as often.

Brilliant09GT

Ah ok I see. Brent did my tune as well. I didnt notice any performance difference when the code came on so im not too worried about it. Just kinda annoying seeing the little yellow engine under the tach. Ill just clear it and hope it doesnt come on very often.

modular81

The slow response code you are getting is actually a very common code you get once going to longtube headers. The reason is your front o2 sensors are further downstream than there original location. This takes them a little longer to heat up. A slight adjustment to the tune's o2 transport delay will usually correct this problem. I had my tuner email me a updated tune file specifally for my bbk longtube's and I mentioned adjusting the o2 transport delay for the relocated front o2's being further downstream and I've never gotten those o2 slow response codes.

adolph807359

I've got s/w longtube and get the check engine light also but notice if i let it warm up a few min. before driving it wont come on as often.