Welcome to the North American Subaru Impreza Owners Club Friday July 19, 2019
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Engine Management & Tuning > Open Source Reflashes

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 01-25-2011, 03:28 PM   #1
AndrewFD3
Scooby Newbie
 
Member#: 210458
Join Date: May 2009
Location: Phoenix AZ
Vehicle:
2003 wrx built ej207
Rally blue

Default rich afr's while cruising?

Hello,

I just got my car tuned about a month ago and was running great, afrs were btween 14?5 and 14.7 while cruising, now while I cruise the afrs go to 12.0 to 10 and its frustrating.... do you think its a tune issue or mechanical issue? Would a bad o2 do this? No check engine light
* Registered users of the site do not see these ads.
AndrewFD3 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 01-25-2011, 03:58 PM   #2
fastnoypi
Scooby Guru
 
Member#: 6886
Join Date: May 2001
Chapter/Region: Tri-State
Vehicle:
MY01 EJ207 HTA35r
AVCS ON!

Default

maybe a possible post maf leak..the ecu is trying to compensate the additional air
fastnoypi is offline   Reply With Quote
Old 01-25-2011, 06:18 PM   #3
AndrewFD3
Scooby Newbie
 
Member#: 210458
Join Date: May 2009
Location: Phoenix AZ
Vehicle:
2003 wrx built ej207
Rally blue

Default

Quote:
Originally Posted by fastnoypi View Post
maybe a possible post maf leak..the ecu is trying to compensate the additional air
Im gonna check for leaks... up up
AndrewFD3 is offline   Reply With Quote
Old 01-25-2011, 10:32 PM   #4
arghx7
Scooby Specialist
 
Member#: 232940
Join Date: Dec 2009
Location: cold
Default

are you sure your gauge is reading correctly? what wideband are you reading? What does the factory front O2 sensor say?
arghx7 is online now   Reply With Quote
Old 01-26-2011, 03:04 PM   #5
AndrewFD3
Scooby Newbie
 
Member#: 210458
Join Date: May 2009
Location: Phoenix AZ
Vehicle:
2003 wrx built ej207
Rally blue

Default

Quote:
Originally Posted by arghx7 View Post
are you sure your gauge is reading correctly? what wideband are you reading? What does the factory front O2 sensor say?
I'm using the aem eugo wideband and had it hooked up for maybe 3 months.. the car was running fine then I did a little pull and since then everytime I drive it will read 14.7 ish for a few mins the it slowly creeps to 13 then to 12 then to 11. No I haven't read the factory o2 yet
AndrewFD3 is offline   Reply With Quote
Old 01-27-2011, 12:11 PM   #6
p00hbear
Scooby Newbie
 
Member#: 211497
Join Date: May 2009
Vehicle:
09 WRX
DGM

Default

try to pull a learning view and look at your fuel trims... i bet they show signs of a leak... maybe something popped under boost when you did that pull
p00hbear is offline   Reply With Quote
Old 01-27-2011, 01:09 PM   #7
AndrewFD3
Scooby Newbie
 
Member#: 210458
Join Date: May 2009
Location: Phoenix AZ
Vehicle:
2003 wrx built ej207
Rally blue

Default

Quote:
Originally Posted by p00hbear View Post
try to pull a learning view and look at your fuel trims... i bet they show signs of a leak... maybe something popped under boost when you did that pull
Thx will do, think it can be my front o2 sensor going bad? I have no check engine light
AndrewFD3 is offline   Reply With Quote
Old 01-27-2011, 08:32 PM   #8
Nuke209
Scooby Specialist
 
Member#: 108089
Join Date: Feb 2006
Chapter/Region: MWSOC
Location: Minnesota
Vehicle:
2003 WRX
NF Performance

Default

last time you cleaned your maf sensor?
Nuke209 is offline   Reply With Quote
Old 01-28-2011, 01:53 AM   #9
ichinobu
Scooby Newbie
 
Member#: 106638
Join Date: Feb 2006
Default

There is a lot more to quality tuning than people realize. Most consumers look for maximum results and guys tune for maximum. That is the starting point for most problems

These ecus performs value look up, cross references and set values for its program executions. You cannot just change a few values here and there. Most values are linked or referenced from one to another to another.

There is no telling where your problem is. The tuning fuel map, timing map, O2, EGT, air leak and who knows. Some people end up causing their own problem. I had some guys to change their air filters and throw everything off and blame the tune. Only you can deduce your problem now after two month.

I would reset (battery disco) your ECU. If the problem clears then it may be the tuning because the learning data in the ECU is cleared. If the problem remains then you may have a physical issue.

Most tuners do not tune for drive ability they tune for power only. Which means they just hit WOT (Wide open throttle) values. When you cruse you are just tipping in and that has its own reference and load values on the fuel maps. That is close loop which means the ecu will use data from the O2 to control AFR's.

You would not believe the things I've seen. Some times guys get their car tuned and swear that its faster and the only thing I find is that the boost values are set to come on earlier thats all.

You have to data log everything to see what is happening. If you have a leak like some one suggested then your will see two issues.

1. The tach will bounce when you decelerate. The engine will either die or choke.
2. Your AFR correction value will go to 25 or max value.

Like I said there are so many possibilities especially when the ecu has been reflashed.
ichinobu is offline   Reply With Quote
Old 01-28-2011, 06:20 PM   #10
RALLInspired
Scooby Newbie
 
Member#: 238881
Join Date: Feb 2010
Default

As it's been said have someone pull a learning view log. If your corrections are too far out or acceptable range then it could be a leak, dirty maf, etc. Did your tuner scale the maf to begin with?
RALLInspired is offline   Reply With Quote
Old 01-28-2011, 09:29 PM   #11
qoncept
Scooby Specialist
 
Member#: 44762
Join Date: Oct 2003
Chapter/Region: MWSOC
Location: Palo, IA
Vehicle:
2013 BRZ
WRB

Default

If you're hitting those AFRs in closed loop (confirm that) you could have a bad front o2 sensor.
qoncept is offline   Reply With Quote
Old 01-29-2011, 01:33 PM   #12
AndrewFD3
Scooby Newbie
 
Member#: 210458
Join Date: May 2009
Location: Phoenix AZ
Vehicle:
2003 wrx built ej207
Rally blue

Default

Quote:
Originally Posted by qoncept View Post
If you're hitting those AFRs in closed loop (confirm that) you could have a bad front o2 sensor.
My buddy tuned my car and it was running fine then all of a sudden (e months later) I have rich afr's. I bought a new front o2 and my cruising afr's are back to normal. When I decelerate the afrs go really rich for a second the leans out... I'm assuming that's normal? I'm going to get it re tuned by a professional I hope that fixes the problem completely
AndrewFD3 is offline   Reply With Quote
Old 02-05-2011, 02:37 PM   #13
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

My car goes rich under light engine braking, and I'm pretty sure that's the intended behavior. It generally only happens very briefly, and even with an AFR gauge in plain sight it's very easy to not notice it happening. But, cruise control + freeway + long mild descent = happens every time, and the engine seems perfectly happy while it's happening.

Under full engine braking, the injectors stop entirely, and both my stock and wideband O2 sensors read 20:1 or so and that's definitely normal. The true AFR is infinite - all air, no fuel.

In other words, it doesn't sound to me like you have a problem.
NSFW is offline   Reply With Quote
Old 03-18-2012, 06:24 PM   #14
danny1058
Scooby Newbie
 
Member#: 313914
Join Date: Mar 2012
Default

Quote:
Originally Posted by AndrewFD3 View Post
My buddy tuned my car and it was running fine then all of a sudden (e months later) I have rich afr's. I bought a new front o2 and my cruising afr's are back to normal. When I decelerate the afrs go really rich for a second the leans out... I'm assuming that's normal? I'm going to get it re tuned by a professional I hope that fixes the problem completely
how can i go more than 14.7 in the table?? or thats the limit
danny1058 is offline   Reply With Quote
Old 03-20-2012, 08:36 PM   #15
Red_Wrx
Scooby Specialist
 
Member#: 158658
Join Date: Sep 2007
Chapter/Region: SCIC
Location: California
Default

Quote:
Originally Posted by danny1058

how can i go more than 14.7 in the table?? or thats the limit
I didn't read this whole thread, but 14.7 is stochiometric meaning your cars most clean performing a/f ratio 14.7:1
Red_Wrx is offline   Reply With Quote
Old 03-20-2012, 08:39 PM   #16
Red_Wrx
Scooby Specialist
 
Member#: 158658
Join Date: Sep 2007
Chapter/Region: SCIC
Location: California
Default

Quote:
Originally Posted by qoncept
If you're hitting those AFRs in closed loop (confirm that) you could have a bad front o2 sensor.
When you car is cold and just starting you will run rich ( open loop) until you reach closed loop. That usually occurs when the thermostat opens and the engine is warmed up.
Red_Wrx is offline   Reply With Quote
Old 03-20-2012, 08:47 PM   #17
Red_Wrx
Scooby Specialist
 
Member#: 158658
Join Date: Sep 2007
Chapter/Region: SCIC
Location: California
Default

If your going lean at cruising are you wot? If so then it makes sense because going lean burns less faster and hotter and hotter the fire the more power you make. If it occurs at a steady rpm then I would look at the injector scaling.
Red_Wrx is offline   Reply With Quote
Old 03-20-2012, 09:59 PM   #18
2.5 turbo hyped
Scooby Specialist
 
Member#: 158810
Join Date: Sep 2007
Chapter/Region: NWIC
Location: Portland Or
Vehicle:
2005 STI and Baja
White

Default

Recalibrate your wideband.
2.5 turbo hyped is offline   Reply With Quote
Old 03-21-2012, 01:05 AM   #19
2Fast4U1DAY
Scooby Specialist
 
Member#: 250152
Join Date: Jun 2010
Chapter/Region: MAIC
Location: Pennsylvania
Vehicle:
2006 WRX Limited
OBP

Default

Quote:
Originally Posted by Red_Wrx

When you car is cold and just starting you will run rich ( open loop) until you reach closed loop. That usually occurs when the thermostat opens and the engine is warmed up.
Closed loop fueling happens MUCH sooner than the thermostat opening up ;-)
That's why we have secondary air pumps to get the oxygen sensor (and catalytic converters) to "light off" temp (aka operating temp where the o2 sensor generates its own voltage), and lower minimum coolant temps for sufficient operation of closed loop fueling.

Also, for clarification purposes, just because the ECU is running in open loop, DOES NOT indicate a rich condition. My AFR's are stoich during cold start warm up.

Last edited by 2Fast4U1DAY; 03-21-2012 at 03:08 PM.
2Fast4U1DAY is offline   Reply With Quote
Old 03-21-2012, 08:19 AM   #20
ehiddenidentity01
Scooby Newbie
 
Member#: 279169
Join Date: Apr 2011
Location: marysville oh
Vehicle:
2004 impreza wrx sti
wrb

Default

Quote:
Originally Posted by AndrewFD3 View Post
My buddy tuned my car and it was running fine then all of a sudden (e months later) I have rich afr's. I bought a new front o2 and my cruising afr's are back to normal. When I decelerate the afrs go really rich for a second the leans out... I'm assuming that's normal? I'm going to get it re tuned by a professional I hope that fixes the problem completely
it does that to compensate for the air coming through the bpv
ehiddenidentity01 is offline   Reply With Quote
Old 03-21-2012, 08:58 AM   #21
quazimoto
Scooby Guru
 
Member#: 70395
Join Date: Sep 2004
Chapter/Region: MAIC
Location: Da-boonies,Va
Default

This is over a year old...........
quazimoto is offline   Reply With Quote
Old 09-22-2014, 10:45 AM   #22
mr.jingles
Scooby Newbie
 
Member#: 343584
Join Date: Jan 2013
Chapter/Region: SCIC
Location: San Diego
Vehicle:
2007 STI Limited
Urban grey

Default

Any updates on this problem?
I have the same issue while cruising. Replaced both rear and front o2 sensors, checked maf and did smoke test. No luck
So I guess I'm gonna get injectors cleaned?
Engine break I get 20.3 which is normal. If I slowly accelerate it's at 14.5. But if I stay at a steady speed it hits 13 and sometimes 12.5.
mr.jingles is offline   Reply With Quote
Old 09-22-2014, 01:26 PM   #23
fenix-silver
Scooby Specialist
 
Member#: 231700
Join Date: Dec 2009
Chapter/Region: MAIC
Location: Central PA
Vehicle:
2004 WRX Wagon
WRB

Default

Are you stock or modded and tuned? What does your learning view look like? Has it always been like this and you just noticed or did it only just start?
fenix-silver is offline   Reply With Quote
Old 10-01-2014, 02:11 PM   #24
IMPERIAL AUTO
Scooby Newbie
 
Member#: 334262
Join Date: Oct 2012
Chapter/Region: Tri-State
Vehicle:
92 CIVICVXH22TURBO
bmw steel grey 400

Default

Most likely needs a re tune ... Switch to speed density
IMPERIAL AUTO is offline   Reply With Quote
Old 03-27-2019, 12:30 AM   #25
itsm3ming
Scooby Newbie
 
Member#: 285031
Join Date: Jun 2011
Location: NOVA
Vehicle:
2015 STI
Launch

Default

any update....5 years later lol.
itsm3ming is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Surging while cruising Sparvy Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo) 11 12-05-2003 02:06 PM
EGTs while cruising between 650-750deg., and max at WOT 800C ok? PaulRex Engine Management & Tuning 3 06-28-2003 07:06 PM
High EGTs while cruising. Chav Normally Aspirated with bolt-on Forced Induction Powertrain 17 12-18-2002 10:19 AM
'Kick' while cruising in cold weather? SlideWRX Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 2 02-27-2002 10:08 AM
popping gear out without clutch while cruising... TerenceT Transmission (AT/MT) & Driveline 6 01-13-2002 12:55 PM

All times are GMT -4. The time now is 12:17 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2019 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.