Rich at idle

e_navarre · 01-15-2022, 02:38 PM

Been having this issue for a while now
Car starts fine, but once it enters CL, the AFR will sit at 12-13 at IDLE, with -25% afr learning. Then it will bog super lean, then super rich again. At WOT the car will throw a p0103 (MAF Circuit High Input, likely due to colder weather)

I replaced my O2, MAF and IAT sensors, checked for obvious fuel leaks and checked all grounds. Had whole intake system smoke tested. Flow tested and cleaned injectors along with new o-rings. Compression tested with new plugs, all numbers came back strong and consistent.

Only other things I suspect could be an exhaust leak or some hidden electrical issues.

Any input would be appreciated. I’m losing my mind and money.

Mod list (that pertains to this issue)
Aeromotive AFPR
Walbro 450 pump
DW hardwire kit
ID 1300cc
IAG braided fuel lines
COBB CAI
Catless DP
Perrin 3in turbo inlet

GeoNV · 01-17-2022, 06:29 PM

Stock injectors? Stock tune? Stock Intake? I had a lot of issues with this after upgrading injectors- basically my injector latency and scaling was a little off. Almost identical symptoms.

e_navarre · 01-18-2022, 01:31 AM

I'm running ID 1300cc injectors with a COBB CAI and Perrin 3in turbo inlet, along with a BCP e-tune. I've been running this setup for over a year without issue. I stupidly didn't check for any exhaust leaks, which seems to be the case due to smoke coming from the up pipe on cold starts***8230;

CharlieSti · 01-30-2022, 10:22 AM

I just had an issue like this on my 04 sti. It turned out to be the connector to the MAF had broken. I went to my local junkyard and pulled the connector and MAF off of an old Impreza and cut the wires to the old one, spliced the ‘new’ connector wires to the old wires. Reset my ECU learning and was all good. Maybe it can be that easy for you?

e_navarre · 03-18-2022, 07:19 PM

Little update.
Still battling this issue. I comp tested and threw new plugs in, no change. Along with the rich idle, now at low rpm during acceleration it’ll lean out for a second (17:1) then go back to normal.

01-15-2022, 02:38 PM	#1
e_navarre Scooby Newbie Member#: 524861 Join Date: Jun 2021	Rich at idle Been having this issue for a while now Car starts fine, but once it enters CL, the AFR will sit at 12-13 at IDLE, with -25% afr learning. Then it will bog super lean, then super rich again. At WOT the car will throw a p0103 (MAF Circuit High Input, likely due to colder weather) I replaced my O2, MAF and IAT sensors, checked for obvious fuel leaks and checked all grounds. Had whole intake system smoke tested. Flow tested and cleaned injectors along with new o-rings. Compression tested with new plugs, all numbers came back strong and consistent. Only other things I suspect could be an exhaust leak or some hidden electrical issues. Any input would be appreciated. I’m losing my mind and money. Mod list (that pertains to this issue) Aeromotive AFPR Walbro 450 pump DW hardwire kit ID 1300cc IAG braided fuel lines COBB CAI Catless DP Perrin 3in turbo inlet Last edited by e_navarre; 03-18-2022 at 07:16 PM. Reason: Update

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01-17-2022, 06:29 PM	#2
GeoNV Scooby Newbie Member#: 518830 Join Date: Sep 2020 Chapter/Region: RMIC Location: Colorado Vehicle: 2009 WRX dark grey metallic	Stock injectors? Stock tune? Stock Intake? I had a lot of issues with this after upgrading injectors- basically my injector latency and scaling was a little off. Almost identical symptoms.

01-18-2022, 01:31 AM	#3
e_navarre Scooby Newbie Member#: 524861 Join Date: Jun 2021	I'm running ID 1300cc injectors with a COBB CAI and Perrin 3in turbo inlet, along with a BCP e-tune. I've been running this setup for over a year without issue. I stupidly didn't check for any exhaust leaks, which seems to be the case due to smoke coming from the up pipe on cold starts***8230;

01-30-2022, 10:22 AM	#4
CharlieSti Scooby Newbie Member#: 528615 Join Date: Jan 2022 Vehicle: 2004 Wrx Sti Red	I just had an issue like this on my 04 sti. It turned out to be the connector to the MAF had broken. I went to my local junkyard and pulled the connector and MAF off of an old Impreza and cut the wires to the old one, spliced the ‘new’ connector wires to the old wires. Reset my ECU learning and was all good. Maybe it can be that easy for you?

03-18-2022, 07:19 PM	#5
e_navarre Scooby Newbie Member#: 524861 Join Date: Jun 2021	Little update. Still battling this issue. I comp tested and threw new plugs in, no change. Along with the rich idle, now at low rpm during acceleration it’ll lean out for a second (17:1) then go back to normal.