Question about closeloop.....

thething96 · Post by **thething96** » Wed Sep 29, 2010 5:02 pm

Just wondering if anyone has good tips to get closeloop to work \"smooth\". I have closeloop enabled till 730 mbar, but in between 1100-1800 rpm, the car feels like it jerks slightly back and forth, very minimal. When looking at the datalog, the jerking is felt when the car goes from rich to lean(because of closeloop), and it happens around 200-300 mbar. It's not that bad, but it could be better. And also, close loop doesn't seem to be steady. I'm back and forth from 12-17 afr, it seems like it never stays close to 14.7 at all. Any ideas? Thanks............

Post by **Gaskleppie** » Fri Oct 01, 2010 5:34 am

o2 fuel trim is the best way to get this better. If you got bigger injectors like 550's RC I would use -45%. O2 fuel trim slows down the proses.

thething96 · Post by **thething96** » Fri Oct 01, 2010 12:14 pm

I'm currently using stock injectors(1995 honda accord f22b2). I will test it out today and post results...........

thething96 · Post by **thething96** » Fri Oct 01, 2010 12:40 pm

On stock injectors, what would be the best fuel trim, if any.?????

relic1 · Post by **relic1** » Fri Oct 01, 2010 12:57 pm

F22B2 = 240cc injectors stock should be good, all though I've noticed that pulling a little seems to help smooth that transition. (I think I'm at about -10%)

Civic VTI-Turbo · Post by **Civic VTI-Turbo** » Fri Oct 01, 2010 3:40 pm

thething96 · Post by **thething96** » Fri Oct 01, 2010 4:38 pm

not to sound dumb, but how exactly does the o2 fuel trim work(as far as how closeloop adjusts afr's)????????????? thanks........

thething96 · Post by **thething96** » Tue Oct 05, 2010 10:49 pm

Well, I ended up having o2 fuel trim set up at -15. Tried different trims, but -15 feels nice. Thanks guys...

thething96 · Post by **thething96** » Sat Oct 09, 2010 9:57 am

Would o2 fuel trim be in any way related to injector offset? The reason I ask is because when I started my calibration, I used a p28 rom, and I had to add +20 on the injector offset section to get idle good. Yesterday, I changed o2 trim from -15 to -20 and the car is acting better than before. So there's a +20 injector offset and a -20 o2 fuel trim, is this just a coincidence????? Thanks

Pandor · Post by **Pandor** » Mon Oct 11, 2010 5:32 pm

thething96 wrote:not to sound dumb, but how exactly does the o2 fuel trim work(as far as how closeloop adjusts afr's)????????????? thanks........

Same question here. O2 fuel trim, Closeloop correction trim, min & max closeloop adjustment... I fail to see the big picture on how these numbers affect closeloop opperation... min/max adjustment are obvious, but how do the other trim settings actually affect these.

JaredKaragen · Post by **JaredKaragen** » Mon Oct 11, 2010 11:20 pm

Look I will spell it out for you; though it is simple. The oem mapping is tuned lean; using closeloop to send rich signals, using the o2 sensor as feedback. If the ecu adds x among and switch to rich takes y time, x = some formula of x and y... And repeat. That's the basics. When you disable the o2 on a stock ecu rom: what happens? It runs lean. There's your 15-20% difference, and after tuning you've added about 10-15% to all lower load areas, the oem mapping needed more base 'overshoot' to do it's work. The oem way of lean vacuum mapping saves a lot of emissions when lifting off the throttle; and thus the reason it is that way. Remember, a percentage is normally based off of an oem or 'root' value, and you are certain it is an original value if it has no user definition for a base value. Thus you must think to account for what is different from the stock configuration.

Pandor · Post by **Pandor** » Thu Oct 14, 2010 7:04 am

Just to make sure I interpret this correctly: o2 fuel trim, trims the map for OEM style (lean to rich) closeloop opperation. (only applies when closeloop is active?). Now, my other question remains, what does closeloop correction trim (under closeloop settings menu)do? Isn't the o2 fuel trim a closeloop correction trim?... ectune should have a lot more popup boxes that actually explain what certain options are for because some are just to confusing... Love the software, but the helpfile isn't helpful at all, nor is the wiki...

JaredKaragen · Post by **JaredKaragen** » Thu Oct 14, 2010 3:12 pm

Oi; I'll say it one more time. The oem mapping is very lean using closeloop to send rich spikes. Since we tune the map different (to stoich) the ecu will pig-rich the motor in closeloop. Trimming back the value closeloop uses fixes the 'overshoot'. Sounds like you are grasping it. This is something that is learned from researching FI computer systems, and books on EFI tuning... The software isn't there to teach you to tune; just enable the ability to tune. The only thing you need to have explained in the app are things that take prescience to how the app works (table reading, datalog settings, etc), and also min/max/nominal defaults. I would expect the app to cost a lot more if it tought you how to tune.

JaredKaragen · Post by **JaredKaragen** » Thu Oct 14, 2010 3:59 pm

Sorry if I sound crabby; I woke up on the wrong side of the bed, I am moving, and unsure where still :/

Bindegal · Post by **Bindegal** » Thu Oct 14, 2010 4:02 pm

Oh and another thing. The closer and more consistent your maps are for a stable AFR in the various loads/rpmÂ´s, the better (faster/more accurately) closed-loop will work in practice. /Allan