HomeDashboardFAQSearchRiviera Questions & AnswersWrite-Ups IndexRegisterRelated LinksMemberlistLog in
Share | 
 

 how low til your fuel trims settle after reset?

View previous topic View next topic Go down 
AuthorMessage
dreww
Junkie
avatar

Location : Dallas
Joined : 2007-04-10
Post Count : 851
Merit : 9

PostSubject: how low til your fuel trims settle after reset?   Tue Apr 10, 2007 1:31 am

any idea? I heard that the older year model a vehicle, it is generally assumed it takes longer for the fuel trims to settle (older softward, older/slower processing speeds, etc.)

Im pretty sure mine dont settle that quick, cause STFT are still logging. Does that mean that LTFT aren't settled yet? Im confused on this aspect still.
Back to top Go down
AA
Administrator
avatar

Name : Aaron
Age : 40
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18306
Merit : 239

PostSubject: Re: how low til your fuel trims settle after reset?   Tue Apr 10, 2007 8:25 am

If you reset the fuel trims after rewrite, it only takes 20 mins or so. If you don't, it could take a week or two from what I've heard. You can reset the trims by pulling the PCM fuse or battery for a couple of hours, but PT has a "reset fuel trims" option even for partial rewrite.

The way I understand LTFT & STFT (I know, it's confusing) is that STFT is the immediate fuel correction that your PCM is commanding. LTFT on the other hand, is "learned" fuel correction based on many STFT results over time. LTFT is the PCM's best guess based on past circumstance. That's the way I think of it anyway. Smaller adjustments create faster LTFT changes, larger ones may take more time to learn, that's my theory.

_________________
'98 SC Riviera 268k miles 298 HP/370 TQ 0-60: 5.79s ET: 13.97 @ 99.28 4087 lb 20.1 avg MPG Nelson Ledges Lap: 1:30
3.4" pulley AL104 plugs 180 t-stat FWI w/K&N 1.9:1 rockers OR pushrods LS6 valve springs SLP headers ZZP fuel rails
KYB GR2 struts MaxAir shocks Addco sway bars UMI bushings GM STB Enkei 18" EV5s w/ Dunlop DZ101s F-body calipers
EBC bluestuff/Hawk HP plus SS lines Brembo slotted discs DHP tuned Aeroforce Hidden Hitch


'05 GTO 49k miles 0-60: 4.8s 16.9 avg MPG Nelson Ledges Lap: 1:26
Because fun
Back to top Go down
http://www.cardomain.com/ride/657082/4
dreww
Junkie
avatar

Location : Dallas
Joined : 2007-04-10
Post Count : 851
Merit : 9

PostSubject: Re: how low til your fuel trims settle after reset?   Tue Apr 10, 2007 11:27 pm

well, hopefully that means my LTFT are gonna change. They were a litlte high +1-2 but the STFT were -1-2. I'll just have to scan again.

have you done the VE tune on your car, or should I say have you finished the VE tune yet?

I haven't tried it yet. driving around with a maf sensor off for a few days didnt sound appealing.
Back to top Go down
Mr.Riviera
Expert
avatar

Name : Matthew
Age : 30
Location : Florida
Joined : 2007-01-17
Post Count : 4334
Merit : 99

PostSubject: Re: how low til your fuel trims settle after reset?   Tue Apr 10, 2007 11:55 pm

so if you drive a bunch of ways all the time. ie; race one minute then cruise for 15mins the LTFT will take a longer time to "level out"?

i dont see + or - 1 or 2 as high, from what i have gathered anything from -5 to +5 is acceptable and it means the long term is doing its job to adjust the fuel.

_________________
1996 with 244k miles, L324" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs.
Back to top Go down
AA
Administrator
avatar

Name : Aaron
Age : 40
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18306
Merit : 239

PostSubject: Re: how low til your fuel trims settle after reset?   Wed Apr 11, 2007 8:45 am

quote: "so if you drive a bunch of ways all the time. ie; race one minute then cruise for 15mins the LTFT will take a longer time to "level out"?"

I believe this is true. After doing a few WOT runs, it seemed my LTFT when up for a while, but settled eventually. My car isn't fully tuned though, so it might be different when you've got everything set right.

I have not done the VE tune.

_________________
'98 SC Riviera 268k miles 298 HP/370 TQ 0-60: 5.79s ET: 13.97 @ 99.28 4087 lb 20.1 avg MPG Nelson Ledges Lap: 1:30
3.4" pulley AL104 plugs 180 t-stat FWI w/K&N 1.9:1 rockers OR pushrods LS6 valve springs SLP headers ZZP fuel rails
KYB GR2 struts MaxAir shocks Addco sway bars UMI bushings GM STB Enkei 18" EV5s w/ Dunlop DZ101s F-body calipers
EBC bluestuff/Hawk HP plus SS lines Brembo slotted discs DHP tuned Aeroforce Hidden Hitch


'05 GTO 49k miles 0-60: 4.8s 16.9 avg MPG Nelson Ledges Lap: 1:26
Because fun
Back to top Go down
http://www.cardomain.com/ride/657082/4
dreww
Junkie
avatar

Location : Dallas
Joined : 2007-04-10
Post Count : 851
Merit : 9

PostSubject: Re: how low til your fuel trims settle after reset?   Thu Apr 12, 2007 11:32 pm

Mr.Riviera wrote:
so if you drive a bunch of ways all the time. ie; race one minute then cruise for 15mins the LTFT will take a longer time to "level out"?

i dont see + or - 1 or 2 as high, from what i have gathered anything from -5 to +5 is acceptable and it means the long term is doing its job to adjust the fuel.

the theory is to have them -5 to 0. You want to be rich, if you have to choose between that and lean. A richer conditions is technically safer than a lean one.

if they are zero or rich to begin with and you go WOT, your fueling is starting from a rich conditions which is desired since WOT commands tons of fuel.
Back to top Go down
 
how low til your fuel trims settle after reset?
View previous topic View next topic Back to top 
Page 1 of 1
 Similar topics
-
» how low til your fuel trims settle after reset?
» A question of fuel trims
» Long Term Fuel Trim
» 85 K100 fuel sensor
» Bike will not start (fuel injector, fuel pump, HALL)

Permissions in this forum:You cannot reply to topics in this forum
Riviera Performance ::   Supercharged 3800 Tech :: Series II Scans, Tuning, PCM-
Jump to: