open loop fueling - Subaru Impreza GC8 & RS Forum & Community: RS25.com

dpjef · 08-26-2006, 02:28 AM

How does open loop fueling work ? Is it pre-programmed maps based on load and corrected with knock only ? Or does it still use the AF sensor ?

Brydon · 08-26-2006, 03:16 AM

It doesn't use the AF sensor. Depending on car and year, there are several maps that are selected by knock. There is ignition and fuel maps. Long term fuel values are also caried into open-loop. Meaning if your car thinks that it is running a little rich most of the time it will pull fuel in open and closed-loop. or visa versa. Subarus are one of the worst cars I have seen for timing maps. Alot of car companies use many ignition maps so if you have knock it pulls timing. Subarus have two maps low det and high det. It's to bad when you turbo a RS that even the high det doesn't pull enough timing.

dpjef · 08-26-2006, 04:21 PM

So it is always better to get the ECU for the engine capacity because I wouldn't get optimal performance from my stock ECU ? (I swapped from NA EJ20 to NA EJ25...and more

)

08-26-2006, 02:28 AM	#1 (permalink)
dpjef 2.7L My: Subaru Parts Join Date: Sep 2002 Location: Belgium Trader Rating: (1) Posts: 356	open loop fueling How does open loop fueling work ? Is it pre-programmed maps based on load and corrected with knock only ? Or does it still use the AF sensor ?

08-26-2006, 03:16 AM	#2 (permalink)
Brydon 2.2L Turbo Car: 93 Teal L; 2001 Aspen RS Fav Mod: IHRTLAG -- License Plate My: Subaru Parts My: Subaru Blog Join Date: May 2006 Location: Vancouver, WA Trader Rating: (3) Posts: 3,657	It doesn't use the AF sensor. Depending on car and year, there are several maps that are selected by knock. There is ignition and fuel maps. Long term fuel values are also caried into open-loop. Meaning if your car thinks that it is running a little rich most of the time it will pull fuel in open and closed-loop. or visa versa. Subarus are one of the worst cars I have seen for timing maps. Alot of car companies use many ignition maps so if you have knock it pulls timing. Subarus have two maps low det and high det. It's to bad when you turbo a RS that even the high det doesn't pull enough timing. __________________ I hope you don't actually believe the things you say. - Jurzeyfresh

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08-26-2006, 04:21 PM	#3 (permalink)
dpjef 2.7L My: Subaru Parts Join Date: Sep 2002 Location: Belgium Trader Rating: (1) Posts: 356	So it is always better to get the ECU for the engine capacity because I wouldn't get optimal performance from my stock ECU ? (I swapped from NA EJ20 to NA EJ25...and more )

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