UCUTEK AFR issue on the 2017+ BRZ/86
 

Ever since I went SC roughly six months ago on my 2018 brz, I've noticed that the AFR actual ( air to fuel ration ) has never matched up with the AFR target ( the set parameter by the tuner ). I contacted Delicious tuning, and they said this is a knows issue, and they have been working with ECUTEK to fix it; that was three months ago...delicious tuning and ECUTEK never made a public announcement about the issue I had to find out myself.

Regarding why the issue is happening, I wasn't told much, except for that some new code that was added to the 2017+ brz and 86 ECU that courses a sensor in the car to not accurately read AFR.

Has anyone experienced this? I've been kind of in the blue, and they haven't been telling me much about when it will be fixed.

If you have a 2017 brz/86 go look at your AFR and see if this is affecting you.

I'm turbo'd on a 2017 with ecutek and I'm not sure what issue you're talking about. My afr's bounce around a few tenths but that's normal

Who is your tuner though? delicious tuning?

Turbo 86, 98 RON, Ecutek, no issues at all.

Tuned at Pulse Racing.

I believe there is some black magic with the port and DI injectors, I recall them talking about it, but, I really don't care about the finer art of tuning as long as it works.

HRI

post a log maybe so we can understand?

Yup, best place to start with potential tuning issues such as this is getting a log of the issue. Then working from there.

This is what I got.

Here is a log.

Usually one uploads logs on datazap.me account and links it :)

There is something very wrong in this tune, or your car

+20% of CL fuel correction and still 14 AFR during WOT pull

Either a leak somewhere or a problem with fuel delivery or a shitty tune

What version of ecutek racerom is your tune ? If your running a 2017+ car then you want to avoid racerom version 10.x completly run latest version 11.1 or go back to vetsion 9. Version 10 on the 2017+ had many bugs, and even quite a few on pre 2017 cars.

This is very likely the culprit. One of version 10's bugs was this exact issue of massive positive CL fuel correction value under WOT and huge negative fuel trims in in idle/cruise conditions with a very lean (16+) target AFR, like the ECU was actively trying to run as lean as possible.

Have you spoken to HRI about this? what did he say?