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Old 11-15-2012, 01:23 PM   #1
OC_Nooby
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Join Date: Feb 2012
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2003 WRX w STI V8

Default Can't tune out a lean spot.

So story goes like this. Car was fine (so to speak) and I had my clutch go out on me. I replaced the clutch and put everything back together. Now I have a lean spot in my tune that I can't get rid off. I though alright, I might have a leak.

Got my TMIC tested and my BOV was leaking. So I lapped the piston and put a new O-Ring and retested. Its seals perfectly now. I also added 2 more washers to make it stiffer. I then tested my motor. No leaks there either.

I have looked at the tune a million times and there is nothing that shows it should lean out.

If it makes any sense my A/F correction drops to zero when it leans out. Maybe the BOV is opening at partial throttle and letting a small amount of air out? though that would make the tune richer as metered air is escaping.

Any ideas would be nice.

Thanks!
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Old 11-15-2012, 02:55 PM   #2
Bamofo
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TurboMike Tuned 2.35

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can you pm me and send the rom over? it always helps to have two sets of eyes. :-)
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Old 11-15-2012, 04:46 PM   #3
sabreofsd
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Check your MAF, might need a little cleaning. Also, copy your MAF scaling and check for any odd spots. You might just be noticing the lean condition now, but it might have existed for a long time. How lean are you getting?
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Old 11-15-2012, 06:05 PM   #4
OC_Nooby
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Quote:
Originally Posted by Bamofo View Post
can you pm me and send the rom over? it always helps to have two sets of eyes. :-)
Is this the development of my new nasioc Bestie?!

Coming your way...somehow.
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Old 11-15-2012, 06:06 PM   #5
OC_Nooby
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Quote:
Originally Posted by sabreofsd View Post
Check your MAF, might need a little cleaning. Also, copy your MAF scaling and check for any odd spots. You might just be noticing the lean condition now, but it might have existed for a long time. How lean are you getting?
Stock MAF table. MAF was recently cleaned.
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Old 11-15-2012, 07:23 PM   #6
sabreofsd
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Stock intake then?
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Old 11-15-2012, 08:19 PM   #7
OC_Nooby
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Quote:
Originally Posted by sabreofsd View Post
Stock intake then?
stock intake to an AMR 3", the turbo inlet should not have an affect, I don't think?

Last edited by OC_Nooby; 11-16-2012 at 01:08 AM.
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Old 11-16-2012, 06:11 PM   #8
OC_Nooby
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Well the lean spot is gone. Not sure if it was my fuelling map tune or the engine compensation map tune I started working on. It's gone none the less.
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Old 11-29-2012, 12:59 AM   #9
Bizko1288
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__________

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Did you disconnect the battery when you replaced the clutch?

This may sounds dumb, but maybe your ECU just relearned the proper correction after it was reset when you repaced that clutch? I am kind of curious just as a fmi, and I like threads with conclusive answers....
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Old 12-04-2012, 12:12 PM   #10
OC_Nooby
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Quote:
Originally Posted by Bizko1288 View Post
Did you disconnect the battery when you replaced the clutch?

This may sounds dumb, but maybe your ECU just relearned the proper correction after it was reset when you repaced that clutch? I am kind of curious just as a fmi, and I like threads with conclusive answers....
I did not disconnect the battery.
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Old 12-04-2012, 02:48 PM   #11
rocketperson7
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MBP

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fwiw, the only thing the ECU "learns" are long term fuel trims, and knock correction

both of which if tuned properly, should not be affecting the engine
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Old 12-10-2012, 04:24 AM   #12
NSFW
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ATP 3076, 6MT, AVO FMIC

Default

VTA BOV?

If yes, the it may be opening intermittently in vacuum. Stiffer springs or moar shimz should help.
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