Target AFR not following fuel map [Ecutek]
 

I'm in the process of self tuning my 2018 turbo'd 86. I'm using Ecutek's Forced Induction tuning guide as a jumping off point. Given their guide and tune is based off a 2013MY EU car, there's probably some differences I haven't been able to surface on my own yet.


I've run into an issue where during a 3rd gear WOT I hear a very unpleasant noise from the engine around 5k RPM. I've never heard anything like this before, but I'm chalking it to aggressive knocking because I believe my AFR is too high. Here's the datazap.


Interestingly it seems like my target AFR refuses to drop to where I have my fuel map tuned to. Where the engine speed peaks at 5300 RPM, the datalog says both my AFR target and actual are around 14.3. If it was following my fuel map, the AFT target (at least) should've been 11.6. Hoping someone can point me in the right direction.

Does it sound like a tin can resonating at 4600-5100rpm, like the cylinder is hollow and echoing suddenly, and then go away?

you have touched something that prevent the ecu go into open loop mode
maybe you lowered the Minimum AFR for open loop table?

Put the 2 lean closed loop tables the same as your main Fuel map
afr target is 14.4 because you are forcing it into closed looop and that s the target at the moment

You can send me privately your tune if you like, i give a quick look at "basic" things and tell you if something is off

@callisto I can't say for sure, I guess it kind of had a tinny sound. I stopped immediately once I heard it, so I'm not sure if it goes away with a higher RPM. It's not just an issue with RPM as I only hear it when I do a WOT pull. Just cruising and slowly building up to 5-6k rpm hasn't been an issue.

@tomm.brz That was my first thought, but I'm not sure what tables control open loop. All three of the Function -> Fueling -> Open loop tables still have the same value as the stock rom, including minimum afr open loop. I'll send my tune shortly.

Also the closed loop afr maps are restricted because I'm using a USDM stock rom.

uas based ROMson 2017+ cars seemto have a lot of errors and weird issues in the ecutek racerom patches, causing all sorts of weird issues including weird lean areas where afr doesn't follow open loop maps and seems to target 14.7 afr for periods.


Seems to happen with reacrom 12 versions sometimes I've has to go back to recerom 11


The euro maps/raceroms are far less error prone than USA ROMs ,if you can switch to euro K00G or K01I

yeah then probably is both bugs and ecutek limitations
I saw your mp will take a look soon

The tinny noise can be reproduced with a healthy engine in stock untuned ROM on a steep uphill in 1st or 2nd, just accelerate smoothly uphill and you’ll hear it after 4500 rpm. It only occurs under load so you’ll never hear it while cruising. I’ll link the thread once search is back up.

@AussieBRZ @tomm.brz Thanks for the input. I recreated my tune based on an EU rom, but still see the same issue. I'm pretty confident I haven't changed anything besides the tables mentioned in the ecutek guide. I used the 12.3 RaceRom patch. I can try version 11, but thought I'd wait to see if there might be any other ideas.
@callisto That's somewhat reassuring. The noise still occurs with the EU rom, but it has a more consistent whining sound as opposed to before where it sound slightly grindy/coarse.

Yeah, it’s quite the noise. I’ve personally heard it on a 2013 with K00G and on a 2019 with K00G, S10C, and U01A.

how did you put a k00g into a pre restyiling they re not really compatible
The sound must be the mix of lean afr, weird camshft positions(as they are in stock form in latest oem calid) too much DI and too high of timings lol

I didn’t, sorry, wrong ROM code. I’ll look it up later but it was whatever was tuning popular back then.

haven t really seen ur tune yet but i ll do and will find what s wrong and fix it for you

US rom sounded different because it has an extra closed loop fueling active which is active even in open loop even until limiter, if the afr target is leaner than 12.6
so probably you run leaner on US calid

Ok the only things i see wrong in the US tune you sent me are
fuel cut resume must be higher than 1.33, put 2
PI to DI% avoid 0% at full load, insert more PI like 20 or 25% at mid rpm high load
Cam timings are kept stock and are inadeguate, try stage2 OTS cam timing and remove 4 Degrees from both intake and exhaust at high load and you are more in the ballpark
Put fuel map lean closed loop the same as you main fuel map (stretch it eventually)
Make afr a bit richer from low rpm to mid rpm
Copy paste exactkly main fuel map into Power AFR maps but it s tricky as it wants under 12. 6 to go into open loop so then modify , over 1.1 of engine load, the cells that are over 12.6 afr and put the like 12.4
Modify Exhaust manifold temp threshold lowering overall of 300 degress, this way you could bypass the power afr maps
Enable ticks on all maps on "Closed loop fuel control options"

i would not use N10C cal with latest racerom, since it seems you re still able to convert calibrations, if you switch to euro rom you could use K00G as it doesn t have any power afr maps and quite free of bugs with 12.1 racerom
Also Q00G and S20G seem ok but they have the power afr maps

Thanks for the insight and info, appreciate you taking a look. That explains my original issue. I can find almost no info about the power afr table, is there a place I can read up on it or do most tuners ignore it (opting for the K00G map). Also I tried flashing the K00G map, but Ecutek complained that it wasn't compatible - is there something I need to do? I'm currently using the Q00G map and all the suggestions you've had more or less fixed the AFR issue. Currently working through closed loop maf scaling and will take a stab at open loop scaling once I get past this next issue:

Despite my fueling now hitting the afr target, I was still having an issue with audible knocking. Even zeroing the advance table did not help. I thought the ignition table from the ecutek guide would get me in the ballpark, but I think they're way too aggressive for what I can do on 91 octane. I've opted to take the "vvt off" ignition base table from the OFT stage2+ tune and interpolate it out for the load I'm doing. Just doing a quick check, the total timing is 5 - 10 degrees retarded in the cells I was seeing knock. Haven't really tested yet, but some partial pulls have me feeling a bit more comfortable. My current goal is to keep fiddling with it until I can eliminate most serious knocking - after that I'll start adding timing back and finding more appropriate afr targets.


I've probably lowered the life expectancy of my engine, which is not what I wanted, but I'm not sure how else I was going to jump into software tuning. If you know of any other sources I can learn from, it'd be much appreciated.:burnrubber:

you re doing good

start low with timing , fix afr first with a bit of speed density maybe (it helps on full throttle pulls)
it s the cam timing the sound i bet , look at cam tables from OTS stg2 tunes but prerestyling, those that have arorund 37-40 of values both in intake and exhaust at mid rpm high load
Then put down of some degrees and use 35-36 as max values for exhaust and 34-35 for intake

Okay, the pre and post styling cam timings are quite similar, but I see the exhaust cam has way more timing in the 3600-4000 range during high load. It also sheds timing in the 2400-2800 range too. Here's the cam timing I copied off the OFT Stage2+ A00G Rom including the following changes:

• Scaled the load and rpm axis. Looks nicer to me this way + matches with the other axis changes I did from the Ecutek guide; let me know if I should not be doing this.
• Took 4 degrees of timing from 0.9 - 2.25 load across all rpm's.
• In the same section, capped the max timing for exhaust and intake: 35-36 and 34-35 respectively.
• Did not touch the low load section

https://i.imgur.com/OVskutK.png
https://i.imgur.com/qubmK0N.png

I'm updating both the high and low det maps. Let me know if you see anything clearly wrong.

that s nice start
for intake make +2 overall so it reaches 35 at 4800rpm then goes down.. blend the end and end it at 10
0.8 engine load column make max 20

exhaust: make +4 untill 2k, then all 35 (can also try 36) until 4800 then fade until 21
Talking about high load

@tomm.brz Can you clarify how I can use a K00G rom? Ecutek says it's not compatible, and only that the 2018 (Q00G) and 2019 (S20G) EUDM roms are supported.

From sleuthing the forums I understand I can modify the calid in 3 places in the rom file to spoof the K00G rom as a different calid, but given that Ecutek saves rom in an encrypted format I would have to use RomRaider instead.

I can modify the calid of an unencrypted rom and then try opening with Ecutek, but this fails because Ecutek maps the definitions incorrectly.

Only other thing I can think of is to find a common ROM that shares both my rom and K00G as compatible roms and use it as a bridge. But it seems odd that Ecutek wouldn't make the whole set compatible.

I ask because I see other weirdness e.g. while engine braking in sixth gear, I don't get a fuel cut sometimes - so instead of afr going extremely lean, it goes very rich instead and will stay like that for as long as I'm engine braking. I'd like to use a known good stable rom instead of a maybe good rom.

You can t do anymore, it is officially blocked by ecutek
you only can if you haven t updated ecutek since May
and NEVER calid hack an ecutek rom it doesn t work it works only for openflash and tactrix

That "bug" i do have it too with K00G ap you would nt fix it
it afflicts every restyling car
it is hard coded by subaru

You can t get fuel cut in sixth gear over 4k rpm morenor less
you can cut it manually by touching throttle very briefly during the engine braking it wil make a little jump and then enter the fuel cut
but still doesn t work at very high vehicle speed and high engine rpm
sometimes also 5th gear is affected the same

Okay, thanks for the clarification. I couldn't find any reference to it on the ft86club or nasioc forums so I assumed it was a very unique bug.

how is your car doing btw?:)

It's in a good place where I feel comfortable driving it around and doing the odd pull while watching the parameters on my phone. I'm pretty happy with the fuel map - I couldn't find a lot of specific info for this platform, but I got a general sense of what is a safe target for a road tune and how to structure the various zones. I was going to see if I could start a separate discussion about that in the future.


Knock isn't completely resolved and I've restarted the ignition timing map multiple times. As mentioned my initial tune had way too much timing causing the audible knock. As a new base I've used the OTS base/advance map with 4 degrees removed. I've also removed about 1 degree per pound of boost. My second attempt at building an ignition map was quite aggressive in retarding knock. I almost never saw any knock in cruising conditions including 6th gear up a hill, but at WOT I had negative timing and was still seeing the odd knock in mid-high load. That didn't make sense to me and I suspected the timing was too low.


So right now I'm on my third attempt which isn't as retarded and now I see around 5-10 degrees of timing during a WOT pull - that seems to work well but I'm seeing more knock during cruise conditions I'm trying to correct. Current knock correction goals are:

• During cruise: Knock events are okay as long as they don't lower advance multiplier
• During WOT: All knock events are bad

if you want u can send me again the tune i can give you hints

I will share my tune and an accompanying datalog shortly!

Somewhat related - does LTFT learning stop when a CEL is lit up?

i havent understood it , STFT never stops but LTFT can delay its activation or not even start at all if some conditions aren t met
why?

Well, I dug into that question for a while and it is very twisty and a lot of threshold adjustments. But there's this one block that, if FFF8AAE2 is set to false, ends up seeming to maybe disable LTFT processing. I wish I could be more certain; still, it's extremely suspicious finding a block of RPM/MAF/speed/load logic with thresholds right at the top of several blocks of LTFT math. Someone could log FFF8AEE2 (on K00G) and see if LTFT only changes when it's true, perhaps.

The above is from K00G; fvar3 is 0.1 at all rpms. I checked a few different calibrations and these exact values and this exact logic seem unchanged from A01G onward.

No luck determining whether CELs disable it or not, but at least there's a possibility of something interesting.

Someone mentioned in the forums before that LTFT learning would stop upon CEL - sounds strange since that may put the car into possibly lean conditions (and I know certain owners who could care less driving around with P0420 lit up.)

A p0420 definitely doesn t stop LTFT
Only certain dtc's i believe

It may or may not, depends on the case
i had a damaged primary o2 sensor which went a lot leaner (its 14.7 would be a 20-21 of real afr when warm) and the ecu wasn't happy of something during the cold start so it delayed LTFT
while LTFT was delayes, fuel trims were limited to "only" -35% or so
when ltft activated suddenly the trims went -80% and the car was extremely lean

Cold start has a "fuel system status" of 1
So if something messes with the cold start conditions and fuel system status stucks at 1 , ltft doesn't start