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Old 09-17-2006, 07:22 AM   #1
Scooby Newbie
Member#: 103373
Join Date: Dec 2005
Default MAF Scaling

I replaced my old panel filter with a K&N Unit. While I was installing into the stock box I noticed the first tuner didn't put the lid on the stock box properly. The Turbo Inlet Pipe was slightly too long and one edge of the box was left with a opening. Trimmed back the Turbo Inlet and made sure the box fitted perfectly on all edges nice and tight.

Went for a drive while logging and now A/F Learning is quite out and the car seems to be running lean. I had to compensate by going a richer in my fuel maps. The car definitly pulls harder especially up top as the old filter was filthy.

How can I fix this issue as I thought about re-scaling the injectors but that's not the right way to do it. Don't I need to compensate with re-scaling the MAF Scaling Maps? Here's a 3rd gear pull...

1=Engine Speed (RPM) 2=Air/Fuel Learning #1 (%) 3=Air/Fuel Correction #1 (%)

*1* *2* *3*
1710 -4.69 0
1780 -4.69 0
1884 -5.47 0
1974 -5.47 0
2064 -5.47 0
2152 -5.47 0
2256 -5.47 0
2356 -5.47 0
2450 -5.47 0
2575 -5.47 0
2689 -5.47 0
2801 -5.47 0
2952 -5.47 0
3089 -5.47 0
3260 -5.47 0
3423 -5.47 0
3621 -5.47 0
3786 -5.47 0
4028 -5.47 0
4226 -5.47 0
4403 -5.47 0
4595 -5.47 0
4786 -5.47 0
4992 -5.47 0
5180 -5.47 0
5331 -5.47 0
5546 -5.47 0
5705 -5.47 0
5878 -5.47 0
6039 -5.47 0
6167 -5.47 0
6251 -5.47 0
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Old 09-19-2006, 06:56 AM   #2
Scooby Newbie
Member#: 103373
Join Date: Dec 2005

Can anyone comment?
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Old 09-19-2006, 02:04 PM   #3
Scooby Newbie
Member#: 73609
Join Date: Nov 2004
Chapter/Region: International
Location: Johannesburg South Africa
2002 wrx


nothing to add
subsribing and a free bump for you - i want to know as well
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Old 09-19-2006, 03:22 PM   #4
Scooby Specialist
Member#: 88322
Join Date: Jun 2005
Chapter/Region: MWSOC
Location: Indianapolis, IN
2009 BMW 135i


I suggest logging what you have, plus MAF g/s, MAF voltage, IAT, front O2 lambda or air-fuel ratio, aftermarket wideband air-fuel ratio, and throttle position.

What you've posted isn't useful at all. Looks like it is full throttle, or at least open loop.
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Old 09-19-2006, 04:59 PM   #5
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Member#: 34860
Join Date: Apr 2003
Chapter/Region: Tri-State
Location: NY
2005 Forester CGM


According to what you posted your car is actually running rich and the car is pulling back fuel.
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Old 09-20-2006, 05:47 AM   #6
Scooby Newbie
Member#: 103373
Join Date: Dec 2005

Thanks guys,

Yeah its a full WOT pull so do I need to log those parameters that Freon said at idle or at cruise only?

Previously at WOT pulls A/F Learning would be dead on 0.
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