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Old 09-20-2019, 03:17 PM   #1
runner19
Scooby Newbie
 
Member#: 39562
Join Date: Jul 2003
Chapter/Region: MAIC
Vehicle:
My02 WRX Sedan 5MT
WR blue

Default Help high A/F Learning.

Hi

Car is a 2002 Subaru WRX manual version.
Car mods listed below.


Please help me with diagnosing a high AF correction. I am not sure if the MAF is faulty or there is an exhaust leak.

Car was tuned and all was well before. Before the problem the AF correction was approx -+5% on a c and d ranges. Replaced front o2 sensor(OEM) about 12 000 miles. Replaced both oem fpr less than 5000km ago. Had injectors cleaned less than 2300 miles ago. replaced boost ref lines to fprs. Cleaned maf (inside as well) with crc maf cleaner. My LM1 wideband tracks OEM afr sensor readings. I tried with another MAF, it has the same issue. I checked the o-ring it appears fine


I am seeing the following values in learning view(max correction in rom 15%) after a long drive + 95 miles


0-5.59 = +14.7
5.60-9.99 = +5.37
10-49.99 = +5.57
50.00+ = -1.07%

Things done after tune.
Changed samco turbo inlet to mishmoto inlet(2.5). Added silicon tube from OEM airbox to turbo inlet.

Had tuner test inlet for leaks, none found(pressured air was used)

Exhaust.

I had exhaust cross pipe leaks at both the flanges. These cross pipe flanges were bent. The manifold flanges were straight. Had cross pipe flanges sanded flat. re-installed with new gaskets and permatex. After repair I took the car to an exhaust place to check for leaks at all flanges, manifold , uppipe and turbo and exhaust.

They could not find any leaks.

They said there may be a leak from the cross pipe itself based on sound(not flanges) But could not verify as the heat shield was on. I could not see any cracks when removing the bottom half of the heat shield.

Logs

I logged the car

I let it warm up, then reset ecu and logged with the maf plugged in and then reset ecu , unpluged maf and logged again.

https://www.amazon.com/clouddrive/sh...nfqm31hmPZ499F


Car mods

2002 Subaru Impreza WRX GDA BUGEYE 5 speed manual sedan

CP Pistons
Eagle rods - ARP bolts
ACL race bearings
STi Nitrided crank

ARP Head studs
STi 11mm oil pump

GFB blow off valve
TD5-20g turbo
TR adjustable WG actuator
4 x 565 cc injectors
MRT Parallel fuel rails with dual fuel regulators

Walbro gss 342 fuel pump (255lph) in tank pump.
MRT Fuel anti Surge tank

MRT STi Larger hood scoop
MRT top mount intercooler.
Samco intercooler hoses
Mishimoto intake hose
Stock airbox with oem filter

SPT 3 inch hi power exhaust - full decat
Grimmspeed uppipe
Mishimoto intake pipe
silcon pipe from airbox to turbo inlet
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Last edited by runner19; 09-20-2019 at 03:34 PM.
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Old 09-22-2019, 05:27 PM   #2
runner19
Scooby Newbie
 
Member#: 39562
Join Date: Jul 2003
Chapter/Region: MAIC
Vehicle:
My02 WRX Sedan 5MT
WR blue

Default

Is this indicative of a post turbo leak? Or exhaust leak. I replace the MAF. Same problem.
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Old 09-26-2019, 04:14 PM   #3
Everich
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Member#: 506763
Join Date: Sep 2019
Default

I'm getting the same thing but on my WRX FA20DIT. I personally upgraded the turbo intake tube to Perrin. I have no leaks. I'm blaming the MAF scaling but I don't have time to mess with it at the moment. My LTFTs are closer to +10 between 2-3k rpms and closer to +4 between 3-4k rpms and only +1 above 4k. Light loads of course. Idle is spot on.

I'm glad it's not my daily driver.
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Old 10-02-2019, 03:35 AM   #4
GHS-TUNING
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Member#: 506471
Join Date: Sep 2019
Default

upload some logs with LTFT and STFT. your AFR correction is all over the place and so is your idle. Also, if you want to upload your ROM so I can take a look at the MAF scaling (after you upload the LTFT and STFT log) I can probably fix it for you.

anything you change before the MAF will more than likely need re-scaling. it may be minor change but usually that's what I see.

BUT it looks like you also still have a leak somewhere which is where the drastic changes are coming from.

log... RPM, AFR correction, AFR, LTFT, STFT, MAF, MAP (load), IAT, Coolant temp, throttle angle, knock correction and that should be enough.
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Old 10-04-2019, 09:03 PM   #5
runner19
Scooby Newbie
 
Member#: 39562
Join Date: Jul 2003
Chapter/Region: MAIC
Vehicle:
My02 WRX Sedan 5MT
WR blue

Default

Hi thanks for the offer. The car is not running atm. I am trying to trace a vac leak and a coolant leak.

I log once I put i all back together again.
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