Closed and open loop

[booya620]

I guess I'm missing something when reading some of the posts on this site. There are several instances where people have referred to open and closed loop in posts. From what I remember open and closed loops refer to oxygen sensors. Closed loop is what your ecu runs while your o2 sensors are heating up and open loop is what your o2 sensors run at once they are full heated. At least this is what i remember. In several posts people have refered to closed loop has running under 3-3.5k and open loop above. I haven't heard these terms used in this fashion before can somebody please explain this to me. Is this in reference to wot only?

[Haltech]

Moving this to ECU Tuning

[Darksun280]

I may be wrong don't hold me too this but on the dash hawk at the bottom right hand corner doesn't that little box that goes C,O and L on a 4 box pid screen tell you if your in open or closed loop? if so im closed loop most of the time with blips of open near or between 2k and 3.5 k while im accelerating slowly im all open loop if coasting OUT of gear. coasting in gear is mainly C and L. Now don't hold me to this just yet I could be completely off.

[superskaterxes]

the car is ALWAYS in closed loop unless you are WOT or you are decelerating with your foot off the gas completely. this is a widely talked about topic so just do some googling....

[kingpin748]

I've seen a few threads now with people claiming it's in open loop above 3000-4000RPM regardless of WOT.

Any truth to that?

[NYpest]

the second o2 sensor feed back triggers closed loop and open loop it is this that tries to keep the car stoich AFR while in closed loop keeping the MPG up

[jweller]

Open loop does NOT use the O2. Closed loop does use the O2.

you use open loop until the car reaches normal operation temps, is in WOT or a high throttle postion, or under decel with the throttle plate closed. there is great benefit in fuel economy and emissions to running in Closed loop, so car makers try to stay in it as much as is reasonable

[NYpest]

thats what i ment

[Darksun280]

That means I'm right Dash hawk tells you what loop your in cause when I started the car tonight it was at "O" and after I let it warm up and started driving normal it goes to "C". Under WOT I start at C then its goes to "L". On deccel out of gear its in open loop and deccel in gear its in closed loop

[AutoXRacer]

So what the hell does the "L" stand for? I've seen that too...

[Darksun280]

Originally Posted by AutoXRacer So what the hell does the "L" stand for? I've seen that too...

No Idea but when I'm wot I'm mainly in L

[NYpest]

Originally Posted by Darksun280 No Idea but when I'm wot I'm mainly in L

Here you go fockers


Fuel System Status (C = Closed Loop, O = Open Loop, L = Open Loop due to Engine Load, F = Open Loop due to a Failure/Trouble
Code, P = Closed Loop with Problems, - = Data not available, U = unknown status)


When this value is displayed on the screen or on the PC from a data log, the following values are used:
0 = Unknown
1 = Open Loop
2 = Closed Loop
4 = Open Loop due to Engine Load
8 = Open Loop with Fault
16 = Closed Loop with Fault


http://www.dashhawk.com/downloads/Da...er%20Guide.pdf

[Darksun280]

Originally Posted by NYpest Here you go fockers Fuel System Status (C = Closed Loop, O = Open Loop, L = Open Loop due to Engine Load, F = Open Loop due to a Failure/Trouble Code, P = Closed Loop with Problems, - = Data not available, U = unknown status) http://www.dashhawk.com/downloads/Da...er%20Guide.pdf

Thank you Tim

[AutoXRacer]

Originally Posted by Darksun280 Thank you Tim

Sweet!!!!

[Laloosh]

I said the rear o2 has significant change over the a/f ratio almost a year ago....
Our car doenst work liek traditional cars....that rear o2 is there for more reasons then just to monitor the cat.

You don't beleive me? Install a diode in your 2nd o2, watch your commanded a/f ratios go from 14.7 to 14.2....yes its not good for gass mileage to have a 14.2 af ratio at idle and cruising, but lets think about partial throttle/transition parts of the rpm band.....could be the very reason my car is still alive today

[Darksun280]

Originally Posted by Laloosh I said the rear o2 has significant change over the a/f ratio almost a year ago.... Our car doenst work liek traditional cars....that rear o2 is there for more reasons then just to monitor the cat. You don't beleive me? Install a diode in your 2nd o2, watch your commanded a/f ratios go from 14.7 to 14.2....yes its not good for gass mileage to have a 14.2 af ratio at idle and cruising, but lets think about partial throttle/transition parts of the rpm band.....could be the very reason my car is still alive today

same here im at 14.2-14.4 like chris and my LTFT are at +5.5 at idle and 10.9 at wot

[SgtP]

you have a diode on your 2nd o2 chris? or are you saying dont do it.

[Darksun280]

Originally Posted by SgtP you have a diode on your 2nd o2 chris? or are you saying dont do it.

don't do it

[NYpest]

Phil we talked about this at the meet remmeber with out that rear o2 sensor feed back your cars is all confused on what its suposed to be doing

[Laloosh]

actually i have installed it 3 days ago. With the cold weather i finally started getting the p0139 code. I was running 14.7 the second i installed the diode, 14.2

with my last tbe, the way they had the o2 positioned also commanded 14.2, then i switched to cpe's tbe and it went up to 14.7, now its back at 14.2 with the diode

[NYpest]

Originally Posted by Laloosh actually i have installed it 3 days ago. With the cold weather i finally started getting the p0139 code. I was running 14.7 the second i installed the diode, 14.2 with my last tbe, the way they had the o2 positioned also commanded 14.2, then i switched to cpe's tbe and it went up to 14.7, now its back at 14.2 with the diode

Im sure with the standback you can fix that but maybe your trying to say its something you found to be productive ?

[Laloosh]

its something i find helpfull.

the car commands 14.2 not 14.7, meaning partial throttle its 14.2 then dips to the 12s the second you touch the gas. No partial boost and 14.7 a/f ratios. Why does it work? Who knows, i dont know the exact role of the 2nd o2, but like i said, it sure as hell isnt just to monitor the cat

[Darksun280]

well mine reads 14.2 with the 02 extender. Chris you whore your suppose to let me know when you do things to your car...

[SgtP]

im at 14.7 now. maybe ill throw on a diode when i install the SB.

[Darksun280]

Originally Posted by SgtP im at 14.7 now. maybe ill throw on a diode when i install the SB.

but you WANT to be at 14.7 lol

[SgtP]

Originally Posted by Darksun280 but you WANT to be at 14.7 lol

damnit stop confusing me! lol so 14.7 is the goal here?

[NYpest]

Originally Posted by Laloosh its something i find helpfull. the car commands 14.2 not 14.7, meaning partial throttle its 14.2 then dips to the 12s the second you touch the gas. No partial boost and 14.7 a/f ratios. Why does it work? Who knows, i dont know the exact role of the 2nd o2, but like i said, it sure as hell isnt just to monitor the cat

maybe its the diode calc of by a bit?

Anyway cool

[NYpest]

Originally Posted by SgtP damnit stop confusing me! lol so 14.7 is the goal here?

I think hes saying that the 14.2 is helping him with the "lean" area @ onset of boost

[Laloosh]

Originally Posted by SgtP damnit stop confusing me! lol so 14.7 is the goal here?

its your call in the end.
Personally until cpe cracks this open close loop bullshit, the richer at partial throttle the better

[NYpest]

Originally Posted by mordant80 Good info, but while we're on the topic. What exactly does open and closed loop mean? What is the purpose?

MPG /NO2 !! Closed loop is supposed to keep you at 100% clean burn (14.7 afr) while crusing and at idel your in closed loop saving gas and being GREEN

[Laloosh]

Originally Posted by NYpest maybe its the diode calc of by a bit? Anyway cool

it probably is, cause what a diode does is change whatever voltage goes through it to roughly .45-.50. That drop from whatever the original voltage was might make the ecu change what it thinks ti stoich.....once again this is all theory and i have no proof nor the tech know how to explain this in detail lol

as for as beeing green lol, im an enviornmental scientist...i also run no cats

[NYpest]

Originally Posted by Laloosh it probably is, cause what a diode does is change whatever voltage goes through it to roughly .45-.50. That drop from whatever the original voltage was might make the ecu change what it thinks ti stoich.....once again this is all theory and i have no proof nor the tech know how to explain this in detail lol as for as beeing green lol, im an enviornmental scientist...i also run no cats

The flashes Cobb/Piasini both adjust the part throttle maping and WOT maps Have you messed with the part throttle tables with the SB i know 0 about the SB so...

[SLS MS3]

Originally Posted by mordant80 Good info, but while we're on the topic. What exactly does open and closed loop mean? What is the purpose?

Closed Loop - Input from the O2 sensors is being used in a feedback loop to keep your A/F ratio at 14.7:1 (stoich) for maximum fuel economy and minimum emissions. The feedback loop is connected, i.e. "closed."

Open Loop - Input from the O2 sensors is ignored. The engine gets its fuel ratios from lookup tables designed to richen the fuel mixture for maximum power. The feedback loop is disconnected, i.e. "open."

[Laloosh]

never messed with part throttle stuff on the standback yet

[whoosh@Realtune]

Originally Posted by Laloosh never messed with part throttle stuff on the standback yet

I'm at 14.2 at idle through MAF xfer changes via the standback

[NYpest]

Originally Posted by whoosh I'm at 14.2 at idle through MAF xfer changes via the standback

nice

[Laloosh]

what were you at before. my maf xfer are 5 for the first row and 8 for half the 2nd row

[whoosh@Realtune]

Originally Posted by Laloosh what were you at before. my maf xfer are 5 for the first row and 8 for half the 2nd row

I need to call you tonight to go over some SB stuff
getting really interesting.....

[SgtP]

yay! you guys do the hard work and ill just reap the benefits!

[oskinosmee]

yea with my first o2 out i stayed in open loop, with it in its closed at idle and so on