Tuning closed loop

[Bindegal]

Just wanted to share some of my experience tuning closedloop on my own car. Engine: Stock ZC1 (identical to US D16A1) T25 turbo, DSM 390cc´s, 2 bar GM map. Narrowband O2 on D14, wideband on ELD for logging. I tuned my part throttle map very carefully to just slightly richer than stoich, AFR 13.8-14.2 or so up to 500mbar. I was surprised to find that closed loop had a very hard time getting the mixture right. Luckily in eCtune we are blessed with a couple of settings that can easily tune in closedloop behaviour accurately with a bit of experience. For now I´m using these settings: Closedloop correction trim: -70% Minimum closedloop adjustment -50% Maximum closedloop adjustment 10% Basically I wanted to limit the ECU´s range of adjustment because the AFR is already very good at all temperatures etc. I might try -80% correction trim or -40% \"minimum closedloop adjustment\" next time I´m out. With the settings above, the AFR seems to be controlled fast and very precisely with very little under/over-shoot. Long-term correction is typically logged as 2 or 3. In my case, if the maximum closedloop adjustment setting was closer to original values (higher) it would never reach AFR 14.7. Insted it was running AFR 11-12-5 most of the time. I suspect the default settings would have worked better if the tables were tuned leaner than 14.7. I was never quite able to get the shiny program to closeloop my car properly on the P72 code I chose to use at the time.... eCtune does it perfectly now. I´m curious as to how others tune these settings. Feel free to comment or share your experience if you wish - others might benefit. /Allan

[glove]

i left my settings stock, just because i have no idea what any of the settings do, or how it affects what the o2 sensor does, what EXTACTLY do minumum and maximum adjustments do? what does the closed loop correction do?

[Bindegal]

As I understand it: Closedloop correction trim = the multiplier applied to all closed loop corrections. 0% = typical stock Honda settings for 240cc injectors. Generally, subtract xx% proportional to your injector size unless fine tuning the sweep also (see below). Minimum closedloop adjustment = this controls how much fuel the closedloop routine is allowed to subtract from the fuel value taken from the table to see a reaction in O2 voltage. Maximum closedloop adjuistment = How much fuel is allowed to be added from the table value to see a reaction in O2 voltage. In effect, the minimum/maximum values also affect how fast the closedloop \"sweep\" lean/rich works. -A low value (0%/0%) will result in a stock, fairly slow sweeping action. -A high value (like -80 / 80%) will result in a faster sweeping action. The ECU will try to reach target AFR faster/more aggressively. Apply a larger closedloop correction trim (see my first post as an example) to reduce the actual amount of fuel subtracted/added. The settings may seem weird at first, but once you get used to them it makes perfect sense. And with a working O2 sensor it´s very easy to dial in a perfect closedloop. Keep in mind though, that for closed loop to function 100% accurately with only a minimum of over/under-shoot in AFR, the tables need to be tuned for a nice even AFR to begin with. And ECT and battery compensations should be tuned accurately as well, as they play a big part especially using large injectors. /Allan

[calvin]

allan you might want to add your explanation to the manual you or working on.

[glove]

thanks for that write up dude, that clears up a lot of questions, basicly i just want closeloop to idle for me, the rest of my maps are perfect, but for the love of god i cant get this thing to idle properly from day to day. one day i get it to 15 afr, at 80 ect next day its at like 13 n shit, at the same ect, its the most frustrating thing in the world. and i set all my iat fuel corrections to 0. I never had any of these issues while i tuned my car in crome. And i dont know what im doing wrong. so i just want to set closeloop to do it for me, it would be sweet if there was an option to enable close loop, only when the car isnt moving.

[yc underground]

Have you monitor and check your battery table offset? Due to voltage change your air fuel will be effected by the change in your injector latency. When your voltage drop in the car due to (under drive pullies, AC, lights on, bad ground, etc.) you may experience some battery voltage change, which then effect the injector pulse / air fuel.

[calvin]

battery table is one of the most important factors

[glove]

i put the injector offset to dsm 450cc 90-93 bluetops, and left 2D settings the way they were, these settings worked fine for me in crome, but the afr's only go outa wack when im idling, not in the rest of the map. im gonna try putting different voltage loads on the car, see if thats what it is.

[calvin]

let the 2d settings the same way.. What are you trying to explain?

[glove]

never mind, thanks to bindegal's write up, i got my closeloop working perfectly. and everything works great. on a side note, i tried putting maximum load on my voltage, and then minimum, the afr only changed by .1, so it wasnt the offset. dont know why i couldnt get it to idle properly in open loop.

[calvin]

ok

[JaredKaragen]

Yeah; I was about to say closeloop at idle? I can see why but if the tune is close to right, your idle should be what you originally set it to (hint hint), or you feel it needs to be active at 0% TPS =D

[glove]

like i said, for the life of me i cant get it to idle properly with just raw values and injector offset, this works for me. my tps never goes below like 2%

[calvin]

don't u think that is wrong that u tps is never lower then 2%

[glove]

lol, ya i should do the calibration eventhough its a stock honda.