I installed the Kooks headers myself over a year ago. Haven't thrown a code since I installed them. They aren't coated either.

 

Zig, what year is your car, and what size is your x-pipe? Just wondering what the difference between our cars is. The codes that I am getting are for cat efficiency, so I know that my wires arnt crossed or burnt. Maybe having the big x-pipe throws more codes than the 2.5 inch?

 

it's an '05 MN6 F55

that may be posible.

my setup includeds:

Kooks 1 3/4 (jethotted) headers
custom (kooks build) collector/cat/reducer
(3" connection to collector, kooks hi-flow cats, 2.5" outlet from cats)
2.5" B&B x-pipe

 

My American Racing headers threw the 430 code every time until I turned off the code with HP Tuners. With HP Tuners you can either tell the computer to not light the MIL or to ignore the test completely.

If you get headers, I highly recommend a tune from a reputable tuner, it makes a huge difference in our car's performance, much more than the tune to my C5 did. I got more SOTP gain from the tune than I did from the headers.

 

Joe_G, do you do your own tuning? If yes what kind of timing at WOT do you run?
Sorry for the thread hi-jack.

As for the codes the Innova is < $100 and well worth it and clears the codes in 30 sec.

 

18 deg (stock).

I have the Innova but the codes come back until you turn them off for good with HP Tuners.

 

Yikes! I am running 25-26( no KR though) . I think I will back that down a bit. Thanks!

 

I had my LG's on for almost 4K miles before I finally got the dreaded engine light for the cats.

It is no big deal, disconnect the battery and drive until it pops on again. I have had a tune and it still does this.

 

They will come back unless you permanently remove them with tuning software. The code readers only allow you to read codes and clear them. You actually need to disable them completely.


Matt

 

Why didn't the tuner disable them?

 

My buddies with cams and heads run 29! And a lot more fuel than I run but that is to be expected. I think my timing is a little low, I might raise it some.

Sorry for the thread hijack. I am getting bad about that.

 

The two main reasons you'll get codes with long tubes and "high flow" cats are that the cats don't get hot enough due to the extra cooling the exhaust gas gets via the long tubes, and that the cats just aren't very good cats. You can use an insulating coating on the long tubes to help keep exhaust gas temperature up. And you can use high efficiency cats (note that the stock cats are high efficiency, and have plenty of flow for even a modified engine). No "high flow" cats can pass EPA certification, their efficiency is too poor.

You can also get codes, and closed loop driveability problems too, if you improperly extend the O2 sensors. You can't just splice in more wire. To function, the O2 sensor element needs atmospheric oxygen on one side and the exhaust stream on the other. No problem getting the exhaust, the sensor element sticks down in the pipe and is directly exposed to it, but atmospheric O2 comes to the sensor down the hollow insulating jacket for the wires. If you do an ordinary wire splice, you'll pinch this O2 source off, and your O2 sensors will not work correctly. You must use proper extension cables made to keep this gas path open.

O2 sensors operate via an electrochemical reaction as O2 diffuses across the hot junction from the oxygen rich atmosphere to the oxygen deprived exhaust gas stream. This generates an electrical current, which is what the ECM measures to determine mixture. This reaction only works if the O2 sensor element is hot enough, if the cats have done their job of oxidizing HC and reducing NOx, and if the sensor junction has an adequate supply of atmospheric oxygen via the hollow wire path. Screw up any of these, and you'll get codes.

 

Cars usually vary out of the factory with regard to tune. In addition, to all the all the other replys your car could be running too rich, too lean, have a small exhaust leak or damage to the oxygen sensor circuit.

You said the sensors ran normal that means you watched the voltage vary as you drove (more cross counts working sensor) A reading of
zero mv on deceleration would indicate a very lean condition.

 

Have Kooks Headers High Flow Cats X Pipe With Borla Touring Exhaust And A Vortex Rammer. Had To Wrap The Bottom With Part # 11002 Thermotec Header Wrap And Thermotec Clamp Kit Part #13001 Works Great. Have A Great Day

 

Get a qualified tuner to handle the tuning. Then remove the o2 sensors altogether. That is what I did and the car runs great. You may consider removing the cats altogether as well.

 

Removing the O2s and leaving the wires is a bad idea because that causes those circuits to be floating causing harm to the PCM hardware drivers and allowing EMI or RFI to be feed back to the ECM.

No 3rd party high flow CAT is legal so why use them?
EPA states that since the car maker must warranty the CAT for 8 years that there is zero reason a car owner would be buying ANY CAT and must have car maker replace with stock ones.

Removing power from battery or ECM is bad idea since each time that is done it flushes out all internal smog tests and forces ECM to have to spent processor time getting all the tests done again and before that is done smog tests could be in a non complete failed state.

Wrapping or coating headers can cause welds to crack. During hot weather or racing the wrapping can cause internal temps too be too high and cause incorrect readings the ECM is making wrong AFR changes

No O2 extender is correct for where ever the stock O2 wiring ends is where the outside air source is. This then could be where the wiring connectors are is near echaust pipes and be sucking in hotter then normal air.

Tuning EM does not turn off the O2s it just turns off their error codes but also means if there is a real problem you will not be informed since the codes are forced off.

Any header requires the ECM to be properly tuned for them and not just turning O2 codes off.

 

The sky is falling, The sky is falling !!!!!!!

 

Because if you want to use the OEM's you have to use "shorty" headers, which are useless. I agree that you should have a quality tune if you have long tubes.

 

Does not make a difference, stock CAT must be used if the car is within the 8 years of the CAT warranty period.
If the smog shop did a visual they would fail the car due to the long tube headers so the high flows gets you no where and if they were used they also by law would fail the car.

I have long tube headers on my C5 and the stock CATs fit just fine.
I then gutted them and my tuner made a tune that still passes tailpipe smog tests

 

You gutted your cats and you give people **** about the law.