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Exhaust Options / Possibilities


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Ok, Gee-Otto need your help. Threw the P0420 CEL Code again.

 

I am running that Magnaflow Dual O2 Cat. It is only 2 months old. I have a hard time believing the cat would fail like that. Could it be that because of the less restriction and higher flow cat it is triggering it?

 

Do you think a CELBoss for the rear O2, like the guys who run race cats or no cats, would solve this problem?

 

 

The cat is in perfect working order the issue is that 1. the gases are free flowing and not heating the cat substrate to the proper temp that the ECU is programmed in relation to acceptable o2 sensor output. You can try to use an anti-fouler or boss to move it out of the stream but I have heard it causes AFR to be off.

 

The best solution and I and talking to this guy about it now would be to simply patch in to the ECU change the voltage range to encompass what the o2 outputs in its new location along with the stock location like say if stock acceptable output is (.5v -1.8v) well the new location cause the output to be say (.2v-1.5v) the lowered end of the threshold is what throws the MIL.

 

The problem is this, the cat actually gets up to temp but it only does it after the programmed delay in monitoring by the ECU. Im not sure of the distance but i think it is somewhere btwn 3-5 miles before it starts to monitor then there is a another preset distance in which the voltage has to fall within the set parameters before is triggers a MIL. This is where my theory runs out b/c some people with 06+ N/A Subarus have track pipes and no MILs for a couple thousand miles then all of a sudden they get it others (like you and I) can only go 20-100 miles before the MILs shows up.

 

I am trying to find out now what all has to be modified to make the ECU happy. :redface:

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Please keep me updated on what you find.

 

I finished the exhaust yesterday. It sounds so quiet. It has a growl, but tamed. It is perfect for my DD and banker vehicle. I will post pics when I get a chance. Possibly get it on a lift.

 

I installed the CELBoss last night and unplugged the ECU overnight. I will see if this will fix it. I just purchased the Casper Electronics extension, and soon I will replace the Rear O2 sensor just to be sure.

 

I will be wrapping the headers the first chance I get. Still haven't gotten around to it with all the other problems that have been happening. The header gets hot quick, especially down here in Texas so I don't know how the temps could be varrying so much to cause an issue. BUT, I will follow orders and use the stuff I already purchased to get this exhaust task completed.

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Ok, let the ECU reset over night and.... NOTHING.

 

Drove about 50 miles today and got CEL again! Two new codes this time P0137 & P0442. What gives? I am exhausting everything I have and I am getting burnt out.

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Ok, let the ECU reset over night and.... NOTHING.

 

Drove about 50 miles today and got CEL again! Two new codes this time P0137 & P0442. What gives? I am exhausting everything I have and I am getting burnt out.

 

dude, don't despair. It's only a CEL.... once you get it all sorted, you'll be stoked.

 

It's not like it doesn't run etc. Still driveable...

 

Take some time and wrap your headers - it'll make a difference.

 

You can have your car stock and never have an issue, or you can mod it and enjoy it... there is a small price to pay sometimes. It'll work out.

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OK, went to AutoZone and bought some HELP! Spark Plug Non-Foulers 18mm. See picture below. They were too short to fit the O2 sensor in.

 

So I took the CELBoss out and just put the sensor into its spot. 30 secs the CEL went away...WTH?

 

Any suggestions? I was thinking of having those HELP! things machined to allow the O2 sensor to fit in it. The CELBoss was not giving enough flow for the sensor to read. I will check tomorrow if just putting it back in the cat will keep the CEL off. It is almost as if I need something in between, i.e. the one HELP! adapter would be just the ticket, just have to machine it out.

 

CELBoss on the right

http://img.photobucket.com/albums/v632/ackershaw/Legacy/IMGP0391.jpg

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After researching the mechanical fix for this, all of the cat-less or race cat guys use both of those HELP! adapters. They come in packs of 2. They drill 1 completely with 1/2" drill bit and just screw it into the other one.

 

http://forums.nasioc.com/forums/showthread.php?t=1473769&highlight=Spark+Plug+Anti+Fouler

 

So their designs for the mechanical fix is: the O2 sensor, drilled out Help! adapter, undrilled Help! adapter and then the cat. They don't touch that second HELP! adapter. That small hole as seen in the picture is the same size. That tiny hole length is of course much shorter than the one on the right, if that makes any sense.

 

So any suggestions? Using one HELP! adapter, keep the small hole just drill out the excess on the inside to allow the O2 sensor to fit in? If I drill it 1/2" all the way through it is just going to get the sensor out of the flow but will still have a large hole and potentially still get the same CEL code as before. What to try first?

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Hi guys, switched out the stock system on my 3.0R Spec.B for a custom made stainless steel cat back system. It has a deep rumble on low revs that turns into a higher pitched growl on high revs. It is definetly louder than stock (which is dead quiet) but not tiring when cuising on the freeway. Here are a few pics on how it looks on the car:

 

http://c4.se/heyman/rear.jpg

http://c4.se/heyman/rear_side.jpg

 

As you can see the end pipes are not that much bigger than stock. They are round instead of oval and they are about an inch longer than the stock pipes.

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You sure it wont work? Two of those HELP! basically take the place of the gold color CELBoss I purchased. What are you suggesting I do GEE-OTTO? Machine the gold one or machining one HELP! adapter?

 

I just got a CEL this morning. Used the car all weekend and all was fine. Have to go check to see what code it is this time.

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Well moving the rear O2 out of the stream of the gases will affect fueling by the ECU. pull the code first I saw on NASIOC a welded both bungs for the sensors side by side and another guy added another cat btwn the two sensors
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  • 3 weeks later...
yea.. everyone leaves it as dual so i gotta do something a little different.. and it sounds pretty good.. its not ricey like you think it would be.. ill get some clips

 

 

Single is just as nice and effective :)

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