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I just installed the HS headers the other day. They seem to improve performance overall, but my SES (Service Engine Soon) light just came on (after about ~50 miles of driving, and after I used to Cruise Control). I know there was something about relocating the 2nd 02 sensor, but where do you move it and how? Also, if I leave it as is, will there be any danger?

thanks,

-Eric
 

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Just in case anyone was wondering, the CEL/SES light will come on if the 02 sensor is not relocated behind the secondary pipe. If you leave it there I'm told it won't do any harm. I have done it yet due to cash flow, but I will eventually.
 

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its not really true.

If everything is done correctly, the CEL will not come on.

I am only running the 2 primary O2 sensors, that is why my CEL is on right now, hehehe. Also, the car is running smooth as silk.............those bottom 2 O2 sensors are useless. :D
 
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I was under the impression that it was the last two that throw the CEL/SES light, I never heard they are useless, unless you mean that if thet werent there the car would still run fine.
 

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I mean I am running the car without the bottom 2 sensors and my car is running like a top....................just the CEL is on. Otherwise, no problems.

I'm still against the need to move the sensors back.
 
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OK the header removes the second cat right? so it is the bottom 2 O2 sensors that are reading the same (wrong info)and that causes the SES light. They dont affect performance.
Where am I going wrong?
if the O2 is relocated that means that it would be located on the secondary pipe that runs the length of the car right?

Please correct me, make me understand.
 

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IF you needed to relocate them, they would have to go behind the cat.

OK, the TWO PRIMARY sensors are teh ones on TOP of the header. Those are the only 2 I have in right now. The bottom two...........after-cat sensors, I do not even have in right now. Car runs great, only the CEL is on..........which isn't a bother. As soon as I get the sensors back in........I will report whether you need to remove them.

I like this site, we have our own forum!!!
 
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Ahhhh
Ok I understand, but it is the last two that cause the CEL light to come ON, wether or not you need them.

Trying to get a good thread going I visit here often but nobody ever posts.
 

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yea I noticed that there are tons of forums but nobody posts.

Anyways, yea, those 2 bottom ones mainly serve to set the CEL off if they're not installed or reading right, otherwise the serve no purpose in the a/f control of the ECU.
 
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Chimmike
I went to the Powertechimports.com site to look at the e-manage (main unit there is the highest $$ I found yet) but I was told that with the ignition harness we would be able to bump our timming.
What is your thought on that. Kind of a expensive upgrade for no real HP gains (unless you know something diff.) but i will need it to go F/I.
 

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we can't really gain anything from bumping the timing, as it is continuously variable according to throttle setting

I have been looking into gettin an Apexi SAFC, as those can allow you to lean or enrich the a/f ratio, plus they look freaking cool.

I'd suggest e-mailing Jamie at powertechimports about that, mention me and he'll hook you up with a good price as well as me getting credit :D

seriously, I think the emanage would only do good if you're running heavy nitrous or FI......as the SAFC is good for bolt ons and low shot Nitrous apps.
 

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Well i still don't get which ones need to be relocated...I'll post up a picture or something.

Hey Pdid, you should have come to the meet tonight. It was in Puente Hills.
 

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e2001gxe said:
Well i still don't get which ones need to be relocated...I'll post up a picture or something.

Hey Pdid, you should have come to the meet tonight. It was in Puente Hills.
the bottom 2, the ones with the longest wires..........you know, the ones on the bottom side of the car. If your install is correct and what not you shouldn't have the CEL on and shouldn't need to move them, but oh well.
 

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If somebody would fill me in on the number and location of the cats and O2 sensors on B15s I can help you out one this one.

So far I am thinking that they have 2 cats and 4 O2 sensors. That what I gather from this thread.

Maybe this will help.

Pre cat O2 sensors are what tells the ECU what a/f mix to use.
Post cat O2 sensors are what tells the ECU if the cat are working correctly. If you get the light for the post cat O2s your car will run fine the ECU just thinks that the cat is messed up.
 
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alright so if the install was done wrong and the 2 needed relocated both would be moved? I thought it was just one, damn I get more confused the longer we talk about this.

e2001gxe I never heard anything about a meet. I have work from 7am-3pm and then go to school 6pm-10:30pm mon-fri so I most likely wouldn't make it unless it was on a weekend, thanks for the heads up though, I will pay closer attention about the meets.

chimmike
I emailed Jamie about a NX kit but I only want a 25-35 shot and was looking for a smaller bottle then the kit he quoted(smaller bottle=less uses that is what I want) could you help me out point me in the right direction. I really thought aboout a NOS sneaky pete but that damn 10oz. bottle would not fly.
 
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PatScottAKA99XE
I think that is kinda the problem here. As I remember it goes
O2---->O2---->cat----->O2---->cat---->02 (stock)
but the header illuminates the second cat
O2---->O2---->cat----->O2---->O2 (header)

This is what I have read over and over, I could be wrong.
 
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PatScottAKA99XE
You edited you post.
You are right about the last two are throwing the light
the question comes down to "What O2 sensor needs to be moved to turn the SES light off"

It can be done.
 

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Has anyone asked HotShot?
Thats my cop-out anwser while I think about this and curse Nissan for such a complicated system.
 
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