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Old 11-19-2012, 05:31 AM   #1
Pandasaurus_rex
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Member#: 157114
Join Date: Aug 2007
Chapter/Region: Tri-State
Location: Plattsburgh, NY
Vehicle:
2002 Impreza WRX
Aspen White & Carbonated

Default Tip-out enrichment problem???

Hi everyone. I just hooked up my AEM UEGO and noticed something right away that seems a little disconcerting. Whenever I lift off the throttle, my AFRs always go super rich, then immediately shoots to a very lean zone on the gauge. The bigger the load change from high to low, the more the AFRs swing. Sometimes it pegs right out at 10:1 inbetween shifts then shoots up to 17+ before it settles back down again upon re-tip-in. I understand that the ECU is probably compensating for the over run by quickly leaning out the mixture, but I'm worried that this will cause tuning issues, especially when doing WOT pulls and shifting. Is there some kind of table I'm missing in the tip-in enrichment area that makes the car stop over running so bad, or is this normal for the engine to do this? BTW, car is perfectly driveable with absolutely no hesitation issues.

Current mods:

DW 650cc injectors, scaled and tip-in adjusted
Catless UP & DP
Stock Airbox
Silicone turbo inlet
Small TD05-16G turbo, 11psi IWG, zeroed WGDC table
Slightly modified OL fueling map, smoothed & slightly leaner than stock
Stock timing map
Zeroed CL/OL transitions

I'm basically ready to start road tuning my car, but want to know if this is something that should be dealt with before I proceed. Please HELP!
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Last edited by Pandasaurus_rex; 11-19-2012 at 08:19 AM.
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Old 11-19-2012, 10:53 PM   #2
Bamofo
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07 STI Limited
TurboMike Tuned 2.35

Default

so im not understanding which part is the issue... the release of boost while your injectors are running at 80-100% causing it to run rich, or the lean condition when you let off the throttle and the injectors turn off because of that.... you can tune out the rich part a little but you cant "not" shut the injectors off....
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Old 11-20-2012, 05:25 AM   #3
Pandasaurus_rex
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2002 Impreza WRX
Aspen White & Carbonated

News

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Originally Posted by Bamofo View Post
so im not understanding which part is the issue... the release of boost while your injectors are running at 80-100% causing it to run rich, or the lean condition when you let off the throttle and the injectors turn off because of that.... you can tune out the rich part a little but you cant "not" shut the injectors off....
It's whenever I lift the throttle. It's easier to see when I'm just cruising. I'll have to go out and take some logs of some high load action to see if it does it still. Usually, I'm cruising along and lift off to slow down. I could be in vacuum or boost. instead of going a little rich, then off the chart lean (closed throttle), it swings super duper rich (10 or less) then swings back to way lean. I remember monitoring my front O2 before I got my WB and the mixture alwas simply went lean, not super-rich-then-lean. Perhaps my WB is revealing more about what's going on, since it can acurately read that low of AFRs.
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Old 11-20-2012, 08:15 PM   #4
bluemk3
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World Rally Blue

Default

Running a bov? Mine does this too more do with avtabov but still does it with the recirc. I think its the delay in the exhaust gas from the time you key off till the time the gas gets to the wide band.. And you will always go lean when off the throttle... There is very little fuel getting injected then.
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Old 11-21-2012, 09:24 PM   #5
BlazeRex
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02 WRX 05 LGT
Slow Automatics

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No WOT issues with tip in like that. 10:1 AFR on tip-out seems excessive. FYI the best I got mine was about 14.0 to 15.5 on tip in/out conditions. Tip in is something that takes a long time to get right. If you can get it close where the ecu doesnt go crazy with the correction swings, I wouldnt stress over it.
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Old 11-23-2012, 09:58 PM   #6
Jubert69
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04 WRX
ej207 spec C 18g

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Quote:
Originally Posted by Bamofo View Post
so im not understanding which part is the issue... the release of boost while your injectors are running at 80-100% causing it to run rich, or the lean condition when you let off the throttle and the injectors turn off because of that.... you can tune out the rich part a little but you cant "not" shut the injectors off....
This.

Quote:
Originally Posted by Pandasaurus_rex View Post
It's whenever I lift the throttle. It's easier to see when I'm just cruising. I'll have to go out and take some logs of some high load action to see if it does it still. Usually, I'm cruising along and lift off to slow down. I could be in vacuum or boost. instead of going a little rich, then off the chart lean (closed throttle), it swings super duper rich (10 or less) then swings back to way lean. I remember monitoring my front O2 before I got my WB and the mixture alwas simply went lean, not super-rich-then-lean. Perhaps my WB is revealing more about what's going on, since it can acurately read that low of AFRs.
When it goes lean, you don't have to worry. Your engine is being fed off your cars momentum. At 0 percent throttle, your car theoretically is running at infinity air/fuel. The running super rich is because fuel is injected in your car, and you stopped airflow.

If it concerns you, do a datalog and see if you're knocking.
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Old 11-28-2012, 10:53 PM   #7
Bizko1288
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__________

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Even though your injectors aren't too large, check out this discussion on Romraider. It sounds like the solution to what you are referencing. It worked for me. But if you are 16 bit like your profile indicates, it might not help you. td-d only has solutions for 32 at the moment.

http://www.romraider.com/forum/viewt...hp?f=25&t=8411
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