New Exhaust with New Check Engine Light - Page 3 - Honda Prelude Forum

That 01 BB6 · 08-15-2011, 02:51 PM

yea....same

KtrainHurricane · 09-27-2011, 08:25 PM

Hey not to hijack the thread and get off-topic, but I was wondering if having 2 resonators "restricted" flow enough for you to notice it?

And I also put on a Vibrant high flow cat, one Magnaflow resonator and OBX twin-loop muffler (all 2.5"), and my CEL just came on. I cleared the code via Advance Auto Parts scanner last night, and it came back on today. Code was P0420 (I think?) and it came up as the cat was bad/missing. I was under the assumption that the only way to get rid of this was tune it out with Hondata...

JDMLOCO · 09-28-2011, 11:33 PM

Hey man, same thing happened to me when I had my Mugen exhaust installed with some Vibrant headers I also had a high flow cat. The way I fixed it was to ask the shot if they had an O2 extension, it makes your O2 sensor pop out a little more since there's more flow with the exhaust and headers it reads the gasses a lot faster. This fixed the problem for me, so if there's a performance shop close by ask them if they have this. Hope you get the problem fixed man, good luck.

That 01 BB6 · 09-29-2011, 08:50 AM

Quote:

Originally Posted by KtrainHurricane

Hey not to hijack the thread and get off-topic, but I was wondering if having 2 resonators "restricted" flow enough for you to notice it?

And I also put on a Vibrant high flow cat, one Magnaflow resonator and OBX twin-loop muffler (all 2.5"), and my CEL just came on. I cleared the code via Advance Auto Parts scanner last night, and it came back on today. Code was P0420 (I think?) and it came up as the cat was bad/missing. I was under the assumption that the only way to get rid of this was tune it out with Hondata...

2 resonator's IMO is perfect for a nice exhaust tone that isn't too loud. As far as the check engine light that came on, it was my front o2 sensor that went bad. I installed a new sensor and was good to go. The check engine light was cleared by simply removing the negative on my battery terminal.

One of your o2 sensors was probably damaged during the install into your catalytic converter, unless there is an exhaust leak.

What JDMLOCO is referring to is a o2 defouler. It is only applicable for the rear o2 sensor on the catalytic converter, the sensor that really does nothing important compared to your front o2.

KtrainHurricane · 09-29-2011, 06:41 PM

Quote:

Originally Posted by That 01 BB6

2 resonator's IMO is perfect for a nice exhaust tone that isn't too loud.

Well what size resonators are you talking about? Two 12"-14"? If so, do you think a single 22"-28" resonator would do the same as two smaller ones put together?

Quote:

Originally Posted by That 01 BB6

One of your o2 sensors was probably damaged during the install into your catalytic converter, unless there is an exhaust leak.

Well I drove around for about a week or so before my CEL came on. I assumed that replacing the o2 sensor would temporarily solve the problem, but eventually the CEL would come back on - since the high flow cat isn't "doing as much" as an OEM cat would...

That 01 BB6 · 09-30-2011, 09:01 AM

I have a 14" Vibrant Ultra Quiet Resonator and a 22" Magnaflow resonator sooo 36" of resonators. I have an automatic so I wanted the sound to be minimal, I'm sure if your driving a manual you would be fine with one 22" resonator.

As far as your whole CEL situation...I went to a shop and they told me my catalytic converter (which was a Magnaflow high flow cat less then 2 months old) was bad. I replaced the front o2 sensor...drove for a week...CEL came back on. I took the negative off my battery terminal two weeks ago and I'm still good.

My advice to you is replace the front o2 sensor. If that doesn't work, I have a brand new never used magnaflow 2.5"in/out catalytic converter you can have for cheap.

usmcmarc · 09-30-2011, 09:16 AM

So what was the outcome of this whole thing? I have a Megan Racing 2.5" Cat-Back..
Looking to add the HyTech Tri-Y Replica with a Magnaflow High Flow Cat

So was this whole CEL thing an exhaust leak, poor install or stray cosmic rays from another galaxy?

KtrainHurricane · 09-30-2011, 09:52 AM

Quote:

Originally Posted by That 01 BB6

My advice to you is replace the front o2 sensor. If that doesn't work, I have a brand new never used magnaflow 2.5"in/out catalytic converter you can have for cheap.

Thanks for the tip...I may try it.

Still, if it DOESNT end up working, I am going to be really pist because this was a brand-new Vibrant high flow cat and has only been on the car for maybe 2 weeks...how the hell does something like this "go bad" in such a short period of time?!

Rycon · 09-30-2011, 01:56 PM

High flow cats dont unlock any power.. if your doing it to be cheap then its ok. Just dont think that its worth spending extra cash on.

That 01 BB6 · 09-30-2011, 06:21 PM

Quote:

Originally Posted by Rycon

High flow cats dont unlock any power.. if your doing it to be cheap then its ok. Just dont think that its worth spending extra cash on.

Everyone knows this I hope, it's not that it is high flow per say. More the fact that it is "higher" flow then your oem piping diameter obv because it's 2.5''.

Ktrainhurricane: I guarantee it is NOT your vibrant cat. See, when you go to ****ty places like autozone or pepboys, they pop out some 40 dollar CEL scanner that only knows basic information and not detailed issues as to what EXACTLY is the issue with your catalytic converter and two o2 sensors.

I took it to a better location, the guy had a $10,000 dollar scanner that had a display on it big enough to play xbox360 on lol. Ended up being the o2 sensor.

usmcmarc: My guess would be when they were re-installing my o2 sensors into the two bungs on my new magnaflow cat during the exhaust install, they damaged them or did not use the proper sealer around the o2 sensors. Although cosmic rays were my second guess.

KtrainHurricane · 09-30-2011, 10:00 PM

Quote:

Originally Posted by That 01 BB6

Everyone knows this I hope, it's not that it is high flow per say. More the fact that it is "higher" flow then your oem piping diameter obv because it's 2.5''.

Ktrainhurricane: I guarantee it is NOT your vibrant cat. See, when you go to ****ty places like autozone or pepboys, they pop out some 40 dollar CEL scanner that only knows basic information and not detailed issues as to what EXACTLY is the issue with your catalytic converter and two o2 sensors.

I took it to a better location, the guy had a $10,000 dollar scanner that had a display on it big enough to play xbox360 on lol. Ended up being the o2 sensor.

Thanks for the input. FWIW, I used an Advance Auto Parts scanner myself which got me the P0420 code. The exhaust was done by a shop with a good reputation down here...the guy does a lot of performance cars and modified work. I do not think he necessarily messed anything up, and I was also not saying that Advance Auto told me my cat was bad - I just did a Google search of P0420 and everything that came up said that code is for a bad catalytic converter...