idle problems after DP and exhaust install
Thread Starter
Registered User
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Joined: Jul 2006
Posts: 2,106
From: Mount Vernon, Washington
Car Info: 2002 WRX
idle problems after DP and exhaust install
the car idled fine before i started. the only mods i have are the downpipe(non
catted) and the exhaust. initially the car idles and drives fine. as soon as the
radiator fans come on the engine starts studdering. the tachometer does not show this but you can hear that its about to stall and has stalled 2 out of the ten
times that the fans have come on. the boost gauge starts to jump when the idle gets rough. really confused. before i re-installed i made sure that the o2 sensor
was clean. i did remove the whole airbox for ease of access and re-installed when i was done. hhmmmm. so i'm wondering if its disconnecting the airflow sensor or the o2 sensor. or maybe i am
totally wrong. any ideas would be very appreciated. i also disconnected the battery hoping an ecu reset would do the trick
catted) and the exhaust. initially the car idles and drives fine. as soon as the
radiator fans come on the engine starts studdering. the tachometer does not show this but you can hear that its about to stall and has stalled 2 out of the ten
times that the fans have come on. the boost gauge starts to jump when the idle gets rough. really confused. before i re-installed i made sure that the o2 sensor
was clean. i did remove the whole airbox for ease of access and re-installed when i was done. hhmmmm. so i'm wondering if its disconnecting the airflow sensor or the o2 sensor. or maybe i am
totally wrong. any ideas would be very appreciated. i also disconnected the battery hoping an ecu reset would do the trick
Last edited by Jakes02; Jul 19, 2006 at 04:37 AM.
Thread Starter
Registered User
iTrader: (1)
Joined: Jul 2006
Posts: 2,106
From: Mount Vernon, Washington
Car Info: 2002 WRX
Problem Solved
in the threads about idling problems i never saw in anyones list of mods the snorkel delete. i noticed that when idling and the fans kicked on it would almost die BUT if i raised the hood it would idle fine with the fans on. i took off the snorkel and latched the hood. when the fans kicked on it idled perfect. i hope this will help someone in the future.
Registered User
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Joined: Dec 2002
Posts: 10,029
From: Sacramento CA
Car Info: 02 Impreza WRX sedan
I read your posts about the rough idle but am confused about whether you tried to run the engine with the complete airbox removed and MAF sensor disconnected.
The MAF sensor is critical to proper running of the engine. This is why installing aftermarket intakes can affect the power output, sometimes for better, sometimes worse. The sensor is very sensitive to even minute changes in airflow.
When in doubt, just use the airbox the way it came from the factory because with your exhaust mods, the intake path is still not a restriction until the mods are such that the engine requires more air. Subaru spent a lot of time and money to develop an intake system that is well-matched to its engines. It's much more involved than just bolting on a piece of tubing because the ECU is carefully mapped using input from various sensors on the engine.
--
0==WW==0
"…axles of evil…" - george w. bush
The MAF sensor is critical to proper running of the engine. This is why installing aftermarket intakes can affect the power output, sometimes for better, sometimes worse. The sensor is very sensitive to even minute changes in airflow.
When in doubt, just use the airbox the way it came from the factory because with your exhaust mods, the intake path is still not a restriction until the mods are such that the engine requires more air. Subaru spent a lot of time and money to develop an intake system that is well-matched to its engines. It's much more involved than just bolting on a piece of tubing because the ECU is carefully mapped using input from various sensors on the engine.
--
0==WW==0
"…axles of evil…" - george w. bush
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