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Old 07-10-2009, 07:28 PM   #1
colorfull
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Default P2096 with TWE header on a 2005 RS

I keep getting that P2096 code (fuel trim system too lean, bank 1) on my 2005 RS wagon ever since summer's back. I installed the header in february and for about 1000 miles the car was driving fine, and all of a sudden, BAM, I keep getting those codes back to back after I clear them.

Now, I was expecting to get P0420 because of the header, but that P2096 code is way more scary since I read that on new imprezas it has an influence on fueling. Usualy this code points to a faulty front O2 sensor but the car has only 50K miles so I don't think the front O2 is to blame.
I don't want to tune that out since that code seems more important than the usual P0420.
And I read that putting a rear O2 sensor spacer will only make things worse when it comes to that P2096.

The only mods to the car are a KN panel filter (the rest of the intake is stock), a LW pully, the TWE header with stock cats (nothing done to the O2 sensors position or wiring) and a custom catback.

Anyone here with a 2005 RS and a TWE that had the same code?
Would coating or wrapping (even if I hate the idea because of Eastern Canada winters) solve the problem?

Williaty, LTracer, Watchunglava, Raceface, Rougeben, all you NA hardcore oldtimers, your input would be very appreciated!!!

Thanks!
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Last edited by colorfull; 07-10-2009 at 07:54 PM.
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Old 07-10-2009, 07:31 PM   #2
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Oh, and since I'm a noob when it comes to logging, what parameters can I log to make sure the problem is not related to that front O2 after all?
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Old 07-10-2009, 08:18 PM   #3
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Do you live where it snow/rains a lot?
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Old 07-10-2009, 08:26 PM   #4
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the K/N filter, even when oiled properly, can cause the MAF to malfunction because of oil residue and dirt that sticks to the residue getting on the MAF sensor elements. also, it lets in a ton more dirt than the OEM or aftermarket paper element filter with unmeasureable gains. The OEM/aftermarket paper element filters flow more than the 25RS/i engine will ever need unless you do some serious work to it.

-clean the MAF sensor with electronic/throtlle body cleaner and be very very careful.
-replace the K/N with stock filter
-reset ecu, start the car and allow to idle for 10 min's min before touching the gas pedal!

if the CEL does not return, you fixed it. if it does, i would investigate the MAF sensor a little more in case it was damaged.

Don't rule out a bad/damaged front 02 sensor. removing the sensor when doing the TWE header install may have damaged/fouled it. they are incredibly sensitive to foreign debris like water and anything except exhaust, really.
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Old 07-10-2009, 08:30 PM   #5
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Quote:
Originally Posted by RaceFaceXC View Post

Don't rule out a bad/damaged front 02 sensor. removing the sensor when doing the TWE header install may have damaged/fouled it. they are incredibly sensitive to foreign debris like water and anything except exhaust, really.
This.
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Old 07-10-2009, 11:57 PM   #6
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Quote:
Originally Posted by RaceFaceXC View Post

Don't rule out a bad/damaged front 02 sensor. removing the sensor when doing the TWE header install may have damaged/fouled it. they are incredibly sensitive to foreign debris like water and anything except exhaust, really.
The sensors were not touched at all since I kept the stock cats. I installed the catback first with the cat and OEM header in place, then unbolted the OEM header and replaced it with the TWE...
But in any case, is there a way to log the car to check if the O2 sensors are functionning within their specifications?

And yeah, I can try replacing the filter and cleaning the MAF. Do you guys think this would be the proper cleaning product as I have a can of this stuff:


Also the spark plugs were replaced last monday, they did look like the engine was running on the lean side (whitish electrodes and a bit eaten) but they were also 25K miles old...
Again, any parameters I could log to check if the MAF sensor's healty?

Is that even possible, logging to see if a sensor's fine, with a tactrix cable?
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Old 07-11-2009, 11:12 AM   #7
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that stuff looks like it would be suitable for the MAF sensor.

yeah you can log the O2 sensors with RR/tactrix 1.3 or 2.0 cable. you can log a bunch of stuff that could help narrow down or show what sensor it as fault, if any. more importantly, you could see if you are actually running lean.
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Old 07-11-2009, 12:06 PM   #8
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Maybe you were extra careful with the sensor, but were you extra careful about keeping debris out of the new header? I did a quick search and this code seems to be common on the 05s. Few people actually solved the problem, but the ones that did seemed to replace the sensor.
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Old 07-11-2009, 12:36 PM   #9
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Quote:
Originally Posted by RaceFaceXC View Post

yeah you can log the O2 sensors with RR/tactrix 1.3 or 2.0 cable. you can log a bunch of stuff that could help narrow down or show what sensor it as fault, if any. more importantly, you could see if you are actually running lean.

Any suggestion as to what parameters to log or threads reading suggestions?
And it's possible to see if I'm running lean without a wideband O2?

Quote:
Originally Posted by bcware View Post
I did a quick search and this code seems to be common on the 05s. Few people actually solved the problem, but the ones that did seemed to replace the sensor.
I searched too and all I could find is related to turbos and NA running catless or with metallic cats.
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Old 07-11-2009, 12:41 PM   #10
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If you changed nothing on your cat it's likely that one of your O2's is failing. Don't think 50k is alot for sensors, I went through two on less miles. If it were a MAF issue causing incorrect fueling you'd probably see a CEL related to the A/F sensor (upstream O2) fuel trims such as:

P0171 Fuel trim malfunction (A/F too lean)
P0172 Fuel trim malfunction (A/F too rich)
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Old 07-11-2009, 03:25 PM   #11
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Quote:
Originally Posted by colorfull View Post
Any suggestion as to what parameters to log or threads reading suggestions?
And it's possible to see if I'm running lean without a wideband O2?



I searched too and all I could find is related to turbos and NA running catless or with metallic cats.
There are a few fuel trim's to look at and there is the primary O2 sensor parameter, but its not very useful in OL unless you have a baseline from before the problems started. even then, it might be useless.

For which fuel trims to look at you might try asking in the ECU forum or PM someone very familiar with which fuel trims mean what. In CL your ECU can probably compensate by using the fuel trim(s) but once you go OL you might be lean of the target.
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Old 07-12-2009, 11:59 PM   #12
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...post 12 and no one has brought up that a pre-O2 exhaust leak will trigger this DTC?

Seriously, reused gasket, dented gasket, a little grit=exhaust leak after header install.
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Old 07-13-2009, 12:08 AM   #13
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I second guessed myself on that one
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Old 07-13-2009, 01:43 PM   #14
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I had to redo all the joints from exhaust ports to cat with new gaskets and wrap the header (already ceramic coated!) to get rid of all CELs with my TWE headers (2005 RS as well). I hate the stuff, but I used that copper gasket maker to make extra sure all the joints were sealed well.

Used to get CELs very often, but have been CEL free for months now

I personally think the header wrap made all the difference.
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Old 07-13-2009, 07:54 PM   #15
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hopefully the OP used new gaskets but i should never assume...

reusing gaskets, even on the exhaust joints after the last O2 sensor, is just silly. they are so cheap and easy to get, besides a temporary/emergency situation there is just no reason to reuse them. Call it $20 worth of insurance for your time, and in some situations, the car's health.
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Old 07-14-2009, 12:57 AM   #16
colorfull
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Quote:
Originally Posted by williaty View Post
...post 12 and no one has brought up that a pre-O2 exhaust leak will trigger this DTC?

Seriously, reused gasket, dented gasket, a little grit=exhaust leak after header install.

WILLIATY, YOU RULE!!!

This weekend I decided to change the tranny oil, and since the TWE header blocks the tranny oil plug, I had to take it down. That's when I noticed that the driver's side was leaking even tought I used new gaskets and cleaned the mounting surfaces all around when put the new header in...
I posted a few months ago about my TWE header hitting the U frame, and I think that the constant hitting created that small intermittent leak.
New gaskets and sealant, and the car's running strong with no CELs.

So i guess that I'll be changing the engine mounts to group N this week, to get rid of the excessive engine shake that sometimes makes the header hit the frame... That must be a first, getting rid of a CEL with new engine mounts...

Thank you all for your input!!!
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Old 07-14-2009, 01:26 PM   #17
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Don't feed his ego too much He already swooped in out of no where and owned everyone's diagnostic skills.
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Old 07-14-2009, 01:27 PM   #18
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Hey, I ownly ownzored you all cause I've been there, broke that.
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Old 07-17-2010, 02:36 AM   #19
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Just for the humor value...

Today my car threw a P2096. I googled. Found this thread. Found my solution to this problem. Will go enact said solution to my own car on Sunday
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Old 07-17-2010, 02:46 AM   #20
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Quote:
Originally Posted by williaty View Post
Just for the humor value...

Today my car threw a P2096. I googled. Found this thread. Found my solution to this problem. Will go enact said solution to my own car on Sunday
Lol pure gold. Someone solving there own problem before they even encounter it
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