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GM "Fuel Trim Enable" #4648044
01/27/18 02:13 PM
01/27/18 02:13 PM
Joined: May 2005
Posts: 2,249
Toronto, Canada
George7941 Offline OP
George7941  Offline OP
Joined: May 2005
Posts: 2,249
Toronto, Canada
Using the Tech 2, under "Fuel System" are four functions
1) Cyl Power Balance
2) Fuel Injector Balance
3) Fuel Trim Reset
4) Fuel Trim Enable

I understand the first three, what does Fuel Trim Enable do? My best guess - when in open loop, force engine to go into closed loop.


2006 GMC Sierra 4.3l, NV3500,G80 , Mobil 1 5W30, Dexcool.
1987 BMW R80 - sold
2015 Honda CBR300R

Staying out of the right lane a lot.
Re: GM "Fuel Trim Enable" [Re: George7941] #4648061
01/27/18 02:28 PM
01/27/18 02:28 PM
Joined: Nov 2006
Posts: 20,570
MA, Mittelfranken.de
Trav Offline
Trav  Offline
Joined: Nov 2006
Posts: 20,570
MA, Mittelfranken.de
That's it in a nutshell, some codes will lock the tables and force open loop, it also starts the learning process AFAIK.


ASE L1, Master. Deutsch Meisterbrief.
Re: GM "Fuel Trim Enable" [Re: George7941] #4648062
01/27/18 02:28 PM
01/27/18 02:28 PM
Joined: Sep 2014
Posts: 1,489
Toronto Canada
WobblyElvis Offline
WobblyElvis  Offline
Joined: Sep 2014
Posts: 1,489
Toronto Canada
I ain't no genius with these things but I would think "fuel trim enable" would normally be set to "enable". This would permit fuel trim when the engine/o2 sensor is up to temp. Disabling fuel trim would effectively stop any fuel trim and keep the system in open loop.

My 2 cents.

Re: GM "Fuel Trim Enable" [Re: WobblyElvis] #4648395
01/27/18 08:42 PM
01/27/18 08:42 PM
Joined: Nov 2006
Posts: 20,570
MA, Mittelfranken.de
Trav Offline
Trav  Offline
Joined: Nov 2006
Posts: 20,570
MA, Mittelfranken.de
That's correct.


ASE L1, Master. Deutsch Meisterbrief.
Re: GM "Fuel Trim Enable" [Re: WobblyElvis] #4648607
01/28/18 04:41 AM
01/28/18 04:41 AM
Joined: Nov 2006
Posts: 20,570
MA, Mittelfranken.de
Trav Offline
Trav  Offline
Joined: Nov 2006
Posts: 20,570
MA, Mittelfranken.de
Okay I understand now what you are saying. Yes normally enabled but for diagnostic reasons you may want to disable it and get readings when the engine is running from the tables alone like it was in open loop.


ASE L1, Master. Deutsch Meisterbrief.

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