Chris_R

Exhaust History:
-OBX headers professionally installed about 6 months ago. - No problems.
-Borla Cat back installed myself about 3 months ago. - No problems.
-RP Supercat installed myself about 400 miles ago. - CEL thrown after about 300 miles.

Current Standing:
I took it to a Mazda dealer and had the code read out (Autozone's OBDII scanner couldn't connect). They charged me to scan it because the aftermarket exhaust was the culprit of the CEL, which is ok - they were friendly about it. They even offered some advice.

Error Code:
The code thrown was P0411 which is "Secondary Air Injection System Incorrect Flow Detected". The tech said it was either not getting enough flow, or was reading too much flow. Given the larger exhaust I am thinking too much flow (I do not feel any restriction).

Dealership Suggestions:
1. Look for an 02 fooler - after searching the forums it seems like people with similar (exhaust manifold-back) setups were having no CEL issues. Could the headers be causing this? I wouldn't think they would make that big of a difference.
2. Find a way to alter the computers 'default' 02 flow reading. So that it is looking for the new flow amount.
3. Reinstall all the stock parts (we both chuckled).

What I'm wondering is do you guys think that it could be caused by the headers? I know the cat-back isn't causing any problems - and most people with the rp supercat have had no complaints (more-over CELs). I ran with the headers installed for a really long time with no issue, but maybe with the headers combined with the supercat it's causing this flow issue.

(I searched for this same situation and didn't find it so it I'm retreading ground, please redirect me to the original thread-thanks!)
Thanks for any help!!
-Chris

by the way I searched the forum for a list of ODBII codes and didn't find them, but here is an online index in case anyone needs them: Maybe we can compile a list of common CELs and throw out common causes? Just a thought.
ODBII Codes: http://autorepair.about.com/cs/troub...l_obd_main.htm

swoope

iTrader: (5)

it is the header... the obx does not come with the air injection ports.

https://www.rx8club.com/showthread.p...ght=obx+header

beers

Chris_R

Awesome, thanks swoope. That is exactly what I was hoping to hear. I think it's interesting that nothing was thrown until the HFC was put on though. I have that header yanked off before I do anything else.
Thanks!
-Chris

O'Renesis

The OBX header I have does have secondary air injection ports. They are not well designed and to my mind are to small for the job, maybe they were an afterthought? Did you use the header gasket provided by OBX? If you did that might be the problem. The OBX header gasket has no holes to match with the air injection ports. In this photo you can compare the stock header and gasket with the OBX attempt. http://www.putfile.com/pic.php?img=4018757
I will take a photo of the OBX header showing the air injection ports and post tomorrow. That way you can compare with your own header.

Chris_R

Now that you mention it, I do remember that air hose connected to the header with no problem. However, I did use the gasket that came with it. I definately SHOULD have noticed if the gasket was covering up those ports...

I would appreciate that picture of your header. I don't want to take my header off unless it's staying off because it was a HUGE pain. I spent 6 hours under the car and still ended up having to take it to a shop to install (He had to machine the part down so it would fit flush.) Fortunately, I took pictures before I installed it so I will be able to look those to compare when I get back on my computer.
Thanks!

BoosTED

iTrader: (2)

Mine has air injection ports as well.





Check to see that the air pump is still hooked up to the header and if the clip that powers the air pump is still connected. The pump is located next to the windshield washer reservoir.

Here is a picture of where the air pump connects to the header (top left side you can see the air pump pipe and one of the bolts that holds it in place).

BoosTED

iTrader: (2)

I also had to machine down the bottom of the flange as you can see in the first photo above I marked where it had to be machined down to.

The stock header gasket was used on mine.

The air pump is used primarily during the first five minutes of the car starting if it wasn't plugged in to power there would be an immediate CEL.

swoope

iTrader: (5)

nice job 4 years... i dont know how i missed the running change, was it ever mentioned????

and something is very odd, that it happened after a cat change... this should be intersting to trouble shoot...

the code leans toward something in air pump..

beers

BoosTED

iTrader: (2)

Thanks Swoope, I mentioned it in the red hot headers video thread.
https://www.rx8club.com/showthread.p...ght=header+obx

If a person is looking for an OBX header that has the air injection ports they have to get one that shows holes on either side of the air injection inlet.

No air injection port (is filled in was never machined out and bolt holes on either side are not present):





With injection bolt holes on either side of the air injection port

BoosTED

iTrader: (2)

I should also mention that the one without the air injection port machined did not need to machine the lower flange around the 3 bolts.

The material used on this flange is high grade material and takes a lot of time with a grinder to grind it down the quarter inch it needs. I suggest using a carbide or diamond tip lathe to machine it down.

O'Renesis

But don't use the OBX header gasket as supplied. You first need to knock out the 3 air pump holes.

mazdatech177

its your aftermarket cat converter, regardless of the fact that its a "high flow" design. ive had this code several times when the factory cat starts to break down and plug up. if there is any question in your mind just compare the prices of the cat you just purchased and a new oem unit from mazda... remember that you get what you pay for

Chris_R

Do you guys think that the stock gasket on the header could have damaged the pump? If it is trying to push air in, and it has nowhere to go, maybe the pump just burned out - or maybe the pressure eventually pushed the hose loose. I'll take a look at the hose and pump tonight when I get home from work. Assuming those look ok, what would you suggest as the next step to diagnose?

Mazdatech177, don't think I'm disregarding your post - I just really don't want the HFC to be the cause. I'm thinking of next replacing the headers with the stock manifold or punching out the gasket. I don't really like the sound the headers give it - it just seems kinda 'breathy' but at the same volume as without.

BoosTED

iTrader: (2)

The stock gasket is way better than the one that comes with the OBX header.

The Mazda one is HKS style. Much better quality and the holes are already punched in it. If you tossed it then I say get a new one, they aren't cheap though.

Oh and the air pump is fairly resilient I wouldn't anticipate it being broken.

Chris_R

I didn't toss it, it was still in really good shape. So I'm going to check the pump and hose, pull the headers, swap out the gasket, and reset the battery. Then I'll drive it around few a few weeks and keep one eye open for that CEL. Thanks for all the help and tips guys. I'll post back as I get things done.

O'Renesis

I bought a stock replacement header gasket and it cost €90 (about $120 ) here in Ireland. I think you should get it for a lot less in the USA.

O'Renesis

I would be a bit worried about the air pump as if it could not push air to the exhaust it might overheat due to the fact that no air was passing through it. The air it is pumping also helps to prevent overheating, me thinks. Best check that it is still pumping air OK.

O'Renesis

If you are taking the header off, do mind checking the size of the exhaust ports? I am gathering as much information I can about the exhaust system but do not have access to a Renesis engine at present to measure the width and height of the ports. I have all the details of the stock and OBX headers but I forgot to measure the dimensions of the ports on the engine at the header face before refitting the stock header . If you could or if anyone else already has these measurements that would be very much appreciated.

Chris_R

Sure, I'll ask my mechanic to measure that while he's got the headers off.

cornrowdpantha

I looked at the pics of the header with them and the one without them, and call me slow, but I didn't see these air ports that have been mentioned. Would someone please be kind enough to point them out, or to describe their location?

Thanks in advance...

O'Renesis

In post 6 the top photo has 3 round ports just below the top mounting holes. These ports are are connected to an air way which the air pump is then connected too with two 6mm bolts, as shown in the second photo. The header without the air ports has no threaded holes to mount the air pump pipe. Hope that enlightens

BoosTED

iTrader: (2)

You can see the little notch in the bottom of the hole for the air pump connection on the header it has a line that goes to the other holes for the air injection.

I have seen the one that doesn't have holes for the bolts on either side of the air injection port and this doesn't have the lines or traces going to the other holes on the engine side of the header.

It was like an afterthought that didn't get finished so they dropped it.

They may have tried for C.A.R.B certification and didn't pass so they decided not to run the air ports in.

What this air pump does is gets the cat hot quicker during the first five minutes of starting the car. Which is when most cars are the least earth friendly.

It shouldn't hinder performance if you don't have it.

Chris_R

I just got back from the shop...Here's some interesting results.
1. The gasket that I had, DID have the holes for 2ndary air pump cut out.
2. I checked the hose after I got the CEL and it was ok. As irony would have it, on my way to the shop this morning, the CEL turned off. My mechanic said that the hose was loose. So I'm wondering if that had just happened, and now the pump was able to push air correctly and therefore cancel the CEL.
3. There was heavy carbon buildup in the 2ndary air channel on the headers. This is, in my opinion, the most likely the cause of the CEL. It was acting like a clogged up artery.

So for now, I have the stock manifold back on and no CEL. (Though like I said it cut off after I left this morning.) If I put the header back on, I will have to find a way to widen that little air groove so it wont be blocked by normal carbon buildup. The air channel is noticably larger on the stock manifold.

Chris_R

O'Ren, he did take this measurement - but I left it on the desk over there. I'll call tomorrow and get it again, but the measurement was (I think) 43.xx mm by 26.xx mm. I don't think he measured all 3 ports.

O'Renesis

Thanks for the info. I think that measurement is probably for the 2 outside exhaust ports. If correct that would make them about 10 smaller in size to the ports on the header, (53mm x 36mm), which makes sense.