8th Generation Honda Civic Forum banner
1 - 20 of 25 Posts

·
Registered
Joined
·
129 Posts
Discussion Starter · #1 · (Edited)
First, my mod list:

P2R spacer + all 3 gaskets
Fujita SRI
Vibrant header + HFC
Custom 2.5" mid section pipe + Vibrant Ultra Quiet resonator
Stock Si muffler
Hondata ECU reflash

And, probably irrelevant mods:
Ingalls Stiffy ETD
HFP suspension

So, here's my situation:

I've been running with this setup for about 7-8k miles, with no CEL. I figured I was in the clear. Just about a week or 2 ago, right after a particularly bad snow storm which I drove in, I might add, I started getting a light.

I suspected luck had finally caught up with me, and the HFC was causing the issue. I checked with both Honda and Advance Auto, and they both agreed (after reading the code) that it was a "sensor out of range" issue. It was throwing 2 separate codes, both related to the O2 sensor.

So, I bought one of those spark plug defoulers, drilled it out so I could fit the second O2 sensor, and plugged it all in. I drove about 20 miles, and BAM, on comes the light again.

Next, I installed an angled defouler in addition to the spark plug defouler (slightly larger spacing with both parts combined), and again, after about 10 miles, on comes the light.

So what's up?? Is my O2 sensor broken? Am I completely screwed?

Any ideas guys?

edit: I just got back from Autozone.


Ok here's the code:

P2A00

Definition: AF Sensor range performance - 11

Probable cause:
Open or short circuit condition
Failed injector or regulator
Engine vacuum leak
Failed AF ratio sensor 11

So, does this help??

The guy at autozone said he thought this code referred to the first (pre-cat) O2 sensor, not the second one.
 

·
Registered
Joined
·
13,332 Posts
Check both O2 sensors, make sure they are good and tight in. If that doesn't help, you might have to buy new O2 sensors, also, try running just the angled defouler. That's what I'm running on my Strup and have never gotten a CEL
 

·
Registered
Joined
·
129 Posts
Discussion Starter · #4 ·
As I mentioned, I tried this with both a short, straight defouler as well as a longer angled defouler.

I cannot run -only- the angled defouler due to the shape of my HFC and the way it's welded onto the flange, it simply won't fit - that's why I have the 2 combined.
 

·
Si-Onara
Joined
·
5,874 Posts
"I suspected luck had finally caught up with me, and the HFC was causing the issue. I checked with both Honda and Advance Auto, and they both agreed (after reading the code) that it was a "sensor out of range" issue. It was throwing 2 separate codes, both related to the O2 sensor."

my guess would be that its not reading enough air passing through the defouler and maybe its not getting any reading at all. They are sure about the specific code numbers telling them this correct?
 

·
Registered
Joined
·
129 Posts
Discussion Starter · #8 ·
my guess would be that its not reading enough air passing through the defouler and maybe its not getting any reading at all.
I would agree with this, except for one thing: the same code is being thrown under 3 different conditions. 1) With no defouler. 2) With the straight, short defouler. And 3) with the long, angled defouler.

They are sure about the specific code numbers telling them this correct?
I will go over lunch and get another reading from a different shop and insist they give me the actual codes so I can give you more info.
 

·
Si-Onara
Joined
·
5,874 Posts
I would agree with this, except for one thing: the same code is being thrown under 3 different conditions. 1) With no defouler. 2) With the straight, short defouler. And 3) with the long, angled defouler.



I will go over lunch and get another reading from a different shop and insist they give me the actual codes so I can give you more info.
Wow thats really odd under 3 different conditions..... I am stumped

Ok man see what it tells you:thumb:
 

·
Registered
Joined
·
129 Posts
Discussion Starter · #12 · (Edited)
Ok here's the code:

P2A00

Definition: AF Sensor range performance - 11

Probable cause:
Open or short circuit condition
Failed injector or regulator
Engine vacuum leak
Failed AF ratio sensor 11

So, does this help??

The guy at autozone said he thought this code referred to the first (pre-cat) O2 sensor, not the second one.
 

·
Registered
Joined
·
2,230 Posts
Ok, if ur saying its ur first 02 sensor(not the post-cat one) then youd easily be able to tell by how ur car's idling. If your car idles fine, and your car accelerates like normal then its not the first one but maybe the second, since the first 02 sensor is used by ur ECU along with the MAF sensor to determine how much fuel to inject. I had the same problem with you, since i have the same vibrant header w/ HFC, with the angled defouler not fitting and throwing CEL's. My defouler when first installed was aimed sort of at the floor to fit the wiring and it threw CEL's all the time. I reinstalled it 4 days ago and had it aim at the engine and no CEL's yet *knock on wood*. And to get it to fit, you have to move the wires around, unscrew the 2nd hook that holds the wire and turn it around, which gives you enough clearance. My CEL code's were different than yours, but hope this helps anyways...
 

·
Premium Member
Joined
·
19,589 Posts
Did some searching on the internet:

CEL codes p2a00 p0138 p0171; please help - HondaCivicForum.com

http://www.8thcivic.com/forums/mech...el-p2a00-p1172-help-needed-3.html#post4817441

I also checked many other sites with the same code. Seems like it is the primary O2 sensor, which combined with an aftermarket intake, throws this particular code.

I am by no means a technician, but it would seem that the possible causes are a bad O2 primary sensor, damaged wiring loom, loom not connected properly, or somehow the intake is causing a lean condition.

Also, it seems like some people have gotten a similar code because of the particular defouler they are using. I have an angled defouler that I bought from Excelerate, similar to the one used on ebay. I have seen a few people with Weapon R who have gotten this code.

JEA86's idea may possibly be the answer without experimenting. Somehow the defouler may not be allowing enough air for the secondary O2 sensor to get a proper reading.

About a year ago, a friend of mine-FG2MN, had a Vibrant RH w/hfc installed. I was there for the installation and dyno run. The car threw a CEL, which I cannot remember at the moment. I had just read that day before coming to the shop, that another guy had gotten a CEL because the wiring loom was not positively connected.

So, I told the mechanic to reconnect the O2 wiring loom. When he redid both of them, the CEL went away.

One more thing: I know it is more work, but I would remove the SRI and reinstall the stock airbox. Since the code is A/F related, it may be that the lack of vanes in the MAF housing is causing a lean condition reading, which may be throwing the CEL. This is why I am such an advocate of using an Si MAF housing when doing any intake.

Hope you can get this straightened out.
 

·
Registered
Joined
·
129 Posts
Discussion Starter · #16 ·
^ Thanks Bill, I didn't get a chance to do any troubleshooting last night, but I'm crossing my fingers about the possibility that just cleaning up and reconnecting the primary sensor may fix me up.

If that doesn't work, I'll move on to the stock airbox solution. I'll keep you guys posted.
 

·
Registered
Joined
·
129 Posts
Discussion Starter · #17 ·
Well, I got the car in to the shop, and as it turns out, the upstream O2 sensor has failed, as I suspected.

So now the real problem is finding a replacement - it seems like an OEM replacement is $180+ which seems a little ridiculous.

Anyone know if I can buy a cheaper part online somewhere?
 
1 - 20 of 25 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top