AF#3 (Rear O2 sensor) correction limits

wrxt4cy · **Posted:** Fri Apr 27, 2012 10:22 am

eminehart wrote:

I haven't tried simulating the narrowband but with over 2000 customers with 08+ WRX's, I have seen just about everything. If someone gets a CEL they email me.

The misfire problem at startup is due to the FPR being overloaded by the fuel pump running at 100% at startup for the first 30-40 seconds.
If you were to check your fuel pressure at startup the needle is bouncing back and forth quickly() abut 15 psi higher then it should be.
On gas its not an issue because it will fire at the rich lambda, e85 is such a rich fuel it won't fire at that rich lambda.
when you first start up the car the oxygen sensor isn't fired up so it can't make the corrections. IT also doesn't completely run off maf at start up.
My little trick to get rid of this is to force AFL at idle to be about -15% by scaling the maf higher in this range. IT won't help the first time you start but after the car learns to pull that -15% then it will start up properly almost every time. It's not perfect but it does help a lot. With an AP I can also 0 out the hot start enrichment and that seems to fix it as well since I no longer get misfires with my car is running close to 0 AFL on speed density and changing this table to 0 fixed it. Unfortunately, we don't have this table defined yet for opensource. It runs rich because of the fuel pressure issue but apparently not rich enough to misfire.

I haven't heard of a many people using the narrow band input trick but I recall seeing at least one other person that used it with success. I too have seen lots of people with missing a broken rear o2 sensors that are having the fueling issue so I certainly know that it does happen.

Thanks for your feedback at the hot start misfire. Hot start enrichment sounds like exactly what I'm dealing with here. I'm also aware of the 100% fuel pump duty cycle at start issue but what I am seeing is the ECU actually targeting a lower AFR. Its too bad we don't have this in OS yet, we could really use it. i'll give your work around a shot and see if that helps. Currently, I just wait to drive it.

eminehart · **Posted:** Fri Apr 27, 2012 10:54 am

dschultz wrote:

There are tables that define initial (fake) load and maf values to be used before any real readings become active. Maybe these tables could be revealed and altered to deal with rich E85 start-up problems.

I have tried these tables out from cobb and they don't seem to help much.
The hot start enrichment I never played with till I went to speed density. The compensation supposedly is only a .3 AFR adder but it made a dramatic difference in my start up.

Nuke209 · **Joined:** Sun Oct 15, 2006 9:10 pm **Posts:** 195

A2ZJ710J

04 STi

throttlehappy · **Posted:** Sat May 05, 2012 8:29 am

wrxt4cy wrote:

eminehart wrote:

I haven't tried simulating the narrowband but with over 2000 customers with 08+ WRX's, I have seen just about everything. If someone gets a CEL they email me.

The misfire problem at startup is due to the FPR being overloaded by the fuel pump running at 100% at startup for the first 30-40 seconds.
If you were to check your fuel pressure at startup the needle is bouncing back and forth quickly() abut 15 psi higher then it should be.
On gas its not an issue because it will fire at the rich lambda, e85 is such a rich fuel it won't fire at that rich lambda.
when you first start up the car the oxygen sensor isn't fired up so it can't make the corrections. IT also doesn't completely run off maf at start up.
My little trick to get rid of this is to force AFL at idle to be about -15% by scaling the maf higher in this range. IT won't help the first time you start but after the car learns to pull that -15% then it will start up properly almost every time. It's not perfect but it does help a lot. With an AP I can also 0 out the hot start enrichment and that seems to fix it as well since I no longer get misfires with my car is running close to 0 AFL on speed density and changing this table to 0 fixed it. Unfortunately, we don't have this table defined yet for opensource. It runs rich because of the fuel pressure issue but apparently not rich enough to misfire.

I haven't heard of a many people using the narrow band input trick but I recall seeing at least one other person that used it with success. I too have seen lots of people with missing a broken rear o2 sensors that are having the fueling issue so I certainly know that it does happen.

Thanks for your feedback at the hot start misfire. Hot start enrichment sounds like exactly what I'm dealing with here. I'm also aware of the 100% fuel pump duty cycle at start issue but what I am seeing is the ECU actually targeting a lower AFR. Its too bad we don't have this in OS yet, we could really use it. i'll give your work around a shot and see if that helps. Currently, I just wait to drive it.

The hot restart issue can be solved, even on E85 with the Base idle Timing table and then the non AVCS Cruise top left timing value. Set the 400rpm Base Idle to 17.27, 600rpm to 16.56 and 800rpm to 15.86 then the cruise table timing needs to be 17.27.

BlackPearl · **Joined:** Fri Dec 04, 2009 11:14 am **Posts:** 35

Forester XT MT EDM 08/09 AZ1G101M - 30040
Subaru Forester XT AT EDM 06 A8DH100P - 2ff38

couldn't find address for my Forester STI jdm 2005 A2WC011E , there is only one search result, and it doesn't looks like that I need, maybe FSTI is enough cool and it doesn't depends of the O2 sensor in stock)

Thanks guys for the mod!

throttlehappy · **Posted:** Wed May 16, 2012 12:22 pm

mrist wrote:

Forester XT MT EDM 08/09 AZ1G101M - 30040
Subaru Forester XT AT EDM 06 A8DH100P - 2ff38

couldn't find address for my Forester STI jdm 2005 A2WC011E , there is only one search result, and it doesn't looks like that I need, maybe FSTI is enough cool and it doesn't depends of the O2 sensor in stock)

Thanks guys for the mod!

AZ1G101N is same as AZ1G101M as well

Oh and have you found the DBW tables to A2WC011E?

BlackPearl · **Joined:** Fri Dec 04, 2009 11:14 am **Posts:** 35

throttlehappy
yes, but not myself, I'm using viewtopic.php?f=34&t=6921&p=67618&hilit=A2WC011E , there are throttle dbw tables, fuel pump.

throttlehappy · **Posted:** Thu May 17, 2012 11:09 am

mrist wrote:

throttlehappy
yes, but not myself, I'm using viewtopic.php?f=34&t=6921&p=67618&hilit=A2WC011E , there are throttle dbw tables, fuel pump.

I added the DBW tables cell values, I will update the coding once I get home if someone else does not beat me to it. The DBW tune in them is horrible, use an 06/07 STi tune if you want better throttle response!

jabbott · **Posted:** Thu Jun 21, 2012 11:24 am

Can someone find it in the A8DH200W rom for me?

Thanks

throttlehappy · **Posted:** Sat Jun 23, 2012 7:59 am

jabbott wrote:

Can someone find it in the A8DH200W rom for me?

Thanks

A8DH200W, A8DH200X, A8DH201X and A8DH202X are all same locations

Add to EcuFlash definition under the line:
<include>32BITBASE</include>

<table name="AF 3 Correction Limits" address="2FF5C" type="2D" level="1" scaling="A/FLearning#1Limits(%)">
<table name="X" type="Static X Axis" elements="2">
<data>High</data>
<data>Low</data>
</table>
</table>

td-d · **Posted:** Sat Jun 23, 2012 8:18 am

wrxt4cy wrote:

eminehart wrote:

I haven't tried simulating the narrowband but with over 2000 customers with 08+ WRX's, I have seen just about everything. If someone gets a CEL they email me.

The misfire problem at startup is due to the FPR being overloaded by the fuel pump running at 100% at startup for the first 30-40 seconds.
If you were to check your fuel pressure at startup the needle is bouncing back and forth quickly() abut 15 psi higher then it should be.
On gas its not an issue because it will fire at the rich lambda, e85 is such a rich fuel it won't fire at that rich lambda.
when you first start up the car the oxygen sensor isn't fired up so it can't make the corrections. IT also doesn't completely run off maf at start up.
My little trick to get rid of this is to force AFL at idle to be about -15% by scaling the maf higher in this range. IT won't help the first time you start but after the car learns to pull that -15% then it will start up properly almost every time. It's not perfect but it does help a lot. With an AP I can also 0 out the hot start enrichment and that seems to fix it as well since I no longer get misfires with my car is running close to 0 AFL on speed density and changing this table to 0 fixed it. Unfortunately, we don't have this table defined yet for opensource. It runs rich because of the fuel pressure issue but apparently not rich enough to misfire.

I haven't heard of a many people using the narrow band input trick but I recall seeing at least one other person that used it with success. I too have seen lots of people with missing a broken rear o2 sensors that are having the fueling issue so I certainly know that it does happen.

Thanks for your feedback at the hot start misfire. Hot start enrichment sounds like exactly what I'm dealing with here. I'm also aware of the 100% fuel pump duty cycle at start issue but what I am seeing is the ECU actually targeting a lower AFR. Its too bad we don't have this in OS yet, we could really use it. i'll give your work around a shot and see if that helps. Currently, I just wait to drive it.

Just reading back through this thread, and read through this. I've found all the hotstart enrichment and post start enrichment tables. Just haven't had the time to post all of this up yet.

If you're still having this problem, when I get back home I can dig these out for you in your rom if you wish.

jabbott · **Posted:** Sat Jun 23, 2012 10:35 am

throttlehappy wrote:

jabbott wrote:

Can someone find it in the A8DH200W rom for me?

Thanks

A8DH200W, A8DH200X, A8DH201X and A8DH202X are all same locations

Add to EcuFlash definition under the line:
<include>32BITBASE</include>

<table name="AF 3 Correction Limits" address="2FF5C" type="2D" level="1" scaling="A/FLearning#1Limits(%)">
<table name="X" type="Static X Axis" elements="2">
<data>High</data>
<data>Low</data>
</table>
</table>

Thanks. Now that i saw the address I figured out how to find it in IDA (never used ida before).
So I did my friends 08 usdm sti

AZ1G201I and AZ1G202I is address :
309CC

jabbott · **Posted:** Tue Jun 26, 2012 12:03 pm

Just wanted to post an update.

On the A8DH200W (usdm 06 wrx) catless, it went from a commanded afr in the 13's while cruising and idle to 14.5.

On the AZ1G202I (usdm 08 sti) catless, it went from a commanded afr constantly switching all over the place to a steady 14.5.

This is a must for any catless car.

BTW, does anyone know why subarus almost always command less than 14.7 (usually around 14.5). Even my 02 wrx does it.

throttlehappy · **Posted:** Wed Jun 27, 2012 1:44 am

jabbott wrote:

Just wanted to post an update.

On the A8DH200W (usdm 06 wrx) catless, it went from a commanded afr in the 13's while cruising and idle to 14.5.

On the AZ1G202I (usdm 08 sti) catless, it went from a commanded afr constantly switching all over the place to a steady 14.5.

This is a must for any catless car.

BTW, does anyone know why subarus almost always command less than 14.7 (usually around 14.5). Even my 02 wrx does it.

Closed Loop Compensation tables do not target 14.7:1

Little more fuel can improve torque and thus you need less air(via less throttle angle) to maintain a constant speed resulting in more torque from less air flow

So say 2% more fuel(14.7 to 14.4 AFR) can increase torque by 10% under cruise meaning 10% less airflow required etc so a slightly richer mixture can actually improve fuel economy as you need less air in the chamber!

dj-phoenixx · **Posted:** Thu Jun 28, 2012 1:00 pm

Hi,
anyone know the adresses in my A2WC522 Rom? I've removed my downpipe cat. So I must make some small changes.

Greets
Marcel

RomRaider

AF#3 (Rear O2 sensor) correction limits

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