liquid_helix136

Hey guys,

I'm having a problem with tuning flashpro that I can't seem to figure out at all. If any of the guys that are familiar with the software have any insight, I'd love to hear it!

I have posted this in the EMS section as well, as some of the good tuners (Gernby) aren't boosted and don't frequent this section often


So with closed loop enabled, but S.Trim values set to +/- 0% (so effectively off), S.Trim will still kick in and screw up my tune in very specific scenarios;

Scenario 1)
Hot starts. The car will start up, use the cranking fuel table and fade to the fuel table and will be right at 14.7, and then S.Trim will kick in, and pull 11% fuel from the map for about 10 seconds, causing the car to lean out to nearly 18.0, and then it goes back to 0% correction, and the car is back at 14.7. Most annoying thing in the world, because I can't drive my car for those 10 seconds, otherwise it will run poorly and very lean.

Scenario 2)
Between EVERY shift, S.Trim will pull that same 11% fuel right at throttle tip in, but only if I get off the fuel entirely, this can be prevented by hovering my foot on the throttle while shifting and can be replicated by decelerating and then getting back on throttle. For about 1 second, S.Trim will kick in, pull 11% fuel, make the car run lean, and then return to 0% correction, where the car runs fine again.

This will happen regardless of what Short trim settings are set at. I just set it to 0% tonight to confirm that it was S.Trim causing this issue. It should not have corrected the fuel AT ALL, since the S.trim settings are set to +/- 0% currently, however despite that being what I'm commanding, it's still wanting to pull fuel.

Here's a link to my Hondata forum post, which has links to the calibration and datalogs since apparently we can't post these types of files on s2ki..

http://www.hondata.com/forum/viewtop...p=89493#p89493

MorngWoodStewie

Funny out of boost at cruising with cruise control or me holding constant let's say 11℅ throttle my short bounces up and down but mi es set kinda high I believe.

MorngWoodStewie

Idle tho. I would not be worried. My Aem that isn't exactly in perfect placement (about 28" away) shows idle at 17 not worried tho.

VitViper

I don't know who did that "tune" for you, but that's a pretty crappy FlashPro calibration. Why are you worried about the static -11% correction when you've got basically disabled closed loop feedback anyway and it's basically running open loop with lean spots to nearly 17 afr (and lots of rich spots lol). Trying to "tune" this ECU by forcing a quasi open loop? You shouldn't even waste your time doing that and dial closed loop in correctly instead.

The static fuel trim on tip in or transient conditions is an ECU learned trim. It happens on pretty much all modern Honda ECU's. The underlying logic of why the ECU learns this isn't totally clear and Hondata has added the ability to "turn it off" on some platforms, with hit or miss results (the settings do not work in many cases and the ECU still applies the learned trim).

liquid_helix136

So then Vit, if it's a learned trim, a more accurate tune would minimize, if not eliminate the applied trim?

MorngWoodStewie

I think he is saying a better closed loop calibration outside of boost like cruising, daily driving is needed. When u get on it is where it should go into open loop and use the reflash where it counts.

The closed loop feedback is much more accurate when correct for cruising, and warm up etc. You will never be able to get open loop to function perfectly outside of WOT pretty much.

King Tut

My guess is this is all caused by a fuel pressure / injector scaling issue.

liquid_helix136

Lol thanks for telling me how closed loop and open loop differ.

I think the part that you and Vit are both missing is the fact that I purposely set closed loop to 0% for two reasons;
1) For easier street tuning, so closed loop isn't interfering with true raw fue values
2) To isolate where the lean spike is coming from, with closed loop set to 0% and the software still using S. trim to pull fuel, I was able to determine why the car is leaning out on shifts.

liquid_helix136

Hondata chimed in on my thread over on that forum, and this is what they said,

"There is a learned AF trim value that the ECU uses. This basically is to quickly set the short term trim to a value after running in open loop and switching to closed loop. eg after a gearshift. The solution is to tune to fuel tables so that the AF is closer to the target.
There also is a min and max for the learned value (look at a 2006 Civic Si calibration). I'll add this in for the next release for the S2000."

So as Vitviper mentioned, it's a hidden feature that isn't available for modification for S2ks (yet). And he was correct on the way to fix the issue, even if he was a little harsh on the quality of my incomplete map and tuning methods

VitViper

I know exactly why you are doing it, you're trying to mimic open loop since you can't just force open loop with a flag in the calibration. The problem arises that if you set all the fuel trims to 0/0 the ecu is silently running off a different set of parameters in the background, and when you change the min/max to something other than 0/0 your fuel map is going to be off when the ECU returns to "normal" closed loop operation. I tested this years ago on the Civics, it doesn't work, lol. I very much doubt the S2K ECU is any different in this.

Yes the min/max is available on the Civic platforms, it doesn't work in most cases (set it to 0/0 and the learned trim still gets applied regardless in many cases). And in many cases no amount of fuel tuning, injector tuning, latency adjustments, etc have any impact on some cars. I've seen this behavior since the inception of FlashPro and been around the block with it. Has little to no impact on drivability and it's a complete was of my time to go 10 rounds with the guys at Hondata about it (it's like nails on a chalkboard annoying to get fixes for issues sometimes).

At this point we're just dropping full CAN BUS compliant M150 ecu's with my programming into the cars guys are doing serious work with and have zero bullshit to deal with -- and all the features on the car work, including cruise control, lol.

When you want a real ECU for your car, let me know, I have the S2K CAN cracked, just waiting on someone wanting to do the conversion.