a/f command problem
 

So ive been using, logging and tuning on oft since just about when it was released for this car but ive never encountered this problem. I went turbo about 3 months back and put on shivs base map, it seem to run fine and log fine for a while but recently its started to give weird readings while cruising.
On start up the car will only go as high as 14.2 when it should be 14.7, after about 10 min of driving i will notice it creeping richer and richer until its about 12.9 at partial throttle actual af and commanded. around this point the car will little by little stay in closed loop longer and the command will read 15.05 but actual af will be 12s-13s light throttle. During full throttle it sometimes goes to open loop and af actual and command is normally about right. I have no fault codes and no noticed exhaust leaks. I have tried different maps and reflashing it. shiv is leaning towards 02 sensor but id like to know if anyone has some knowledge on this before i drop a couple hundred on a sensor.
this is a pic of it cruising on the highway, fully warmed up.

Don't quote me but isn't the window our ECU see fairly small? I didn't think it would read past certain readings both high and low.

i believe you can set your limits and scaling inside romraider

commanded afr is the afr the ecu is targeting
afr is the measeured afr at front o2 sensor

maybe check maf is clean, no intake leaks check catch cans an pcv valves etc

if its a boost leak past maf, maf will meter the air then some lost so it will run rich as less air getting to engine than maf saw.

yep you can rescale front o2 to read down to about 10 afr with reasnoble accuracy, stock scaling stops at about 12 from memory

Okay sweet I am glad I was right
Is it possible that the AFR difference he is seeing is due to thr fact that the stock ecu cant read far enough in either direction to match the commanded AFR?

so your thinking the maf would cause it to throw inaccurate commands like that? 15:05 is what it wil throw on decel

afaik Commanded AFR of 15 shouldn't happen unless it's cutting fuel e.g. you're decelerating.

yes it very weird the ecu commanded afr is 15 and engine load 0.48,

i dont know whats in tune tables but it very difficult to get the ecu to target anything leaner than 14.7 under load

The open loop fuel table generally wont let you target anthing leaner than 14.7

and closed loop table is an offset from 14.7 ie values are generally negitive eg -0.3 in closed loop table ,ecu will target 14.7 - 0.3=14.4

if you put positive values or zero in the closed loop table then weird stuff happens ltft is disabled.

also i once messed up my closed loop table by highlighting entire table and applying an offset in romraider it leaned out all the cells richer than 14.7 , and the cells at 14.7 showed 14.7 , but when i drove the car it targeted rearly lean values. I had to copy in a fresh table to fix it even though it looked ok something was weird.

if you try to enter values leaner than 14.7 manually romraider wont allow it.

maybe it a rearly weird tune corruption

the stock o2 sensor scaling will read as lean as 20 on deceleration fuel cut.

ya exactly but this is a base turbo map from shiv. everyone else gets the same thing lol. it didnt use to do this. funny cause it doesnt even try to run what the command is, it just goes rich the whole time never leaner then 13.0 under throttle while it says 15.05...my values are 14.7 at the leanest, but when i start the car it will command 14.2 and get richer and richer till it locks out and just says 15.05.. im at a loss

http://datazap.me/u/grip-hooligan/ri...og=0&data=1-10

here is a log of it if you wanted to take a peak. maybe kodename has an idea (i dont know how to tag people on here:lol:)

hmm certianly weird when it gous open loop it seem to go strange and hold open loop and afr and commanded afr drift apart.

i did not study logs when i had that open loop table issue but it did similar thing,

kodename 47 is on holidays sking to tag just put @ infront of username

so i swapped maps again, at first it was kinda retarted while idling it would flicker 10.0 af then back to 14.7 then the oft shut off i adjusted the cable and the car has been perfect all day. command and all staying at 14.7 when it should, no freaking out after weeks of it doing that its just fine :iono: i guess its ok now lol

Id give it a couple of days and at least a 100 miles or more driving before you get too excited it may be related to some weird fuel trim learning or something else that only shows up after a while.

this maybe why people dont see it they only log just after a flash possibly and not after a week or so.

yea it might be back idk. it seems good sometimes but it started doing it after the oft tablet cord got loose while driving and set of some cluster codes and puts it in limp mode. cleared them all and this issue happened again.. otherwise it has been having alot of writing problem to the ecu, keeps failing to write. maybe ecu or the oft is shot

Write fails not good ,suspect its the obd socket in car worn or loose sockets. Try a short obd cable extender right angle one best as you car cable tie it in and it does not hang down. Then lug oft into other end that way your not further wearing the car socket, if it rearly bad you may need to refit a new obd socket in car.

luckily its only 5 wires if i need to repin it lol

I've been getting the same weird logging issues too:. 15.05 commanded AFR, OL, light to medium throttle. Actual measured AFR looks fine, car runs great, no CELs, no write failures. The only change I made to fueling is I made the CL load comp tables have offsets that make it match the POL table. It generally runs richer than the OTS CL map.

I followed 3 guys with OFT in the last year and all of them have that kind of offset in the logged command afr value

During closed loop the rear 02 sensor can influence the commanded afr value log AFCorrection #3



If af#3 corrections not disabled then you will see some offset in commanded afr by the rear 02 sensor.

I see the offset also with rear O2 Disabled

thats strange
did you disable (zero) both tables ?

So I logged almost everything I could find in OFT related to O2 and AFR for this and it looks like commanded AFR going to 15.05 under throttle correlates to something called a/f sensor voltage going below ~2V. There is no scaling matching this in the OFT defs I have; OFT has a front O2 sensor scaling in current, not volts.

https://datazap.me/u/protoformx/log-....96&tmax=15.06

I'll do more correlation analysis on this log in Octave after dinner.

OK, here are some plots for:
commanded AFR = 15.06
RPMs increasing
Fuel system = OL

https://imgur.com/a/Ym8HhIv
First pic has the x-axes all sync'd are time in seconds.
https://i.imgur.com/M2CDFiP.png?1
Second pic is just the bottom right 2 plots with the gaps taken out. X-axes are just samples, not time.
https://i.imgur.com/6zwPgZW.png?1
Is there a measured AFR limit of ~13.5 for CL?

Post the oft log to www.datazap.me will be esier to read

If this is for me, I did in the post prior.

you commanded AFR is not logging correctly what calid is your tune ? are you using OFT V4 tunes ?

commanded afr may be being offset by the rear 02 sensor readings can you log AF#3 ? or alternative disable rear 02 sensor corre ctions by zeroing the two AF#3 correction tables

the rest looks ok, but i think your problem is just logging is incorrect for your rom/tune

http://www.ft86club.com/forums/showthread.php?p=2909412

Thanks for the comments. I Just checked my defs in RomRaider and found I had the wrong one at the top (ZA1JN10D, my car is ZA1JK00D and it was the next one down). I think these logging quirks started around the same time I downloaded that def. Could writing a tune with the following year's def cause this? AFAIK, the logger would be using the ZA1JK00D defs, right?

I'm not sure I'm understanding your linked forum post, so let me see if I have it right. If the correct cal ID doesn't fix this, you're saying I can set the limits for my AF #3 sensor to 0/0, even if my RomRaider def puts it in a different group ("ALPHA AF 3 (Rear O2 Sensor)", not "Fueling - AF Correction/Learning") from what was shown in your screen cap?
https://i.imgur.com/LNO2Uve.png?1

Correcting the Cal ID def didn't fix it. Now flashing a tune with the rear O2 corrections disabled.

Grab the latest OFT V4 tunes for K00D that should sort your logging issue they will be based on K01I

correcting def calid wont help

you need the K01I based V4 tunes

https://support.openflashtablet.com/...7-us-6at-v4-03

the earlier V4 2017 plus tunes has logging issues

Zeroing the AF 3 sensor corrections didn't fix it either.

I got my OFT in September. Nothing new has been released for my Cal ID since July.

check your K00D tune with hex editor
8000 ZA1JK00D
10000 ZA1JK00D
about 11000 ZA1JK01I

if its V4.03

Found these:
ZA1JK00D @ 0x8000 & 0x100000
ZA1JK01I @ 0x11FE51

I'll re-download the latest files and see if they're different.

Just did the same check on the latest files I just downloaded and got the same results.