Hey all, I was wondering if anyone knew the cause or why the desired AFR would richen up as the RPMs get higher at WOT. I'm targeting 13.2 across the board during WOT (which is perfect for these cars) but above 5000RPM+ the desired AFR slowly creeps down to 11.9 which is very rich for this platform.
Any help would be appreciated. I have attached my tune, 3rd gear log and a dyno chart to show the drop in power when the richer mixtures are introduced.
Desired AFR going rich at high rpm
Desired AFR going rich at high rpm
- Attachments
-
3rd gear tip.csv- (3.93 KiB) Downloaded 179 times
-
- Screenshot 2023-12-28 115138.png (31.84 KiB) Viewed 2218 times
-
- Mazda 3 SP23 - RON 98 [Open] v1.00.vtune
- (44.46 KiB) Downloaded 186 times
2007 Mazda 3 MPS | 219kw / 474nm @ wheels
-
CrazyCanadian
- Posts: 23
- Joined: July 4th, 2021, 8:32 pm
Re: Desired AFR going rich at high rpm
It's catylist over temp protection... Try reducing the Cat temp afr corrected table... Put them back to stock.. Also what are you using to log AFR's?? The O2 sensor is listed as a Narrow band O2 and it's sitting at 0.02V... If that is in fact a narrow band O2 sensor, that's a really low voltage for what you are commanding... Also you can't properly tune in Open Loop with a narrow band...
Re: Desired AFR going rich at high rpm
Thanks for your response, I'll have to play around with the catalyst temp tables then, I never really understood what they were for. I log my AFRs with a wideband sensor and a gauge on my dash that I had replaced with the that O2 sensor, hence is why it reads 0.02V the entire time (not plugged in). In terms of AFRs they match fairly well with desired across the board so MAF is dialled in decently.
2007 Mazda 3 MPS | 219kw / 474nm @ wheels
-
CrazyCanadian
- Posts: 23
- Joined: July 4th, 2021, 8:32 pm
Re: Desired AFR going rich at high rpm
I haven't played with this stuff on a mazda, so I can't tell you for certain how those tables work.. But I've seen similar stuff with GM's and Fords..
If you have a cat on the car, you want to leave those tables stock otherwise you risk melting down the cat.. If you are running the car hard on the track.. Or if you live close to the mountains like me.. This is where those tables generally come into play.. You've leaned the car out quite a bit which increases cat temps.. If you do have a cat and plan to modify those tables.. take a temp gun with you and start physically checking the cat temp so you do push it to far..
Where I live, if you drive 2 hours outside of the city you do a slow climb up a mountain gaining about 2000 feet of elevation... This is the type of situation where you'll melt the cat down and get stranded with a plugged exhaust before you've finished the climb..
If I had to guess the 3d table helps determine the threshold(Where over temp enrichment is activated) and the 2d table works constantly in the back ground to calculate the temp as your driving..
I'd also get a second bung welded in so you can run the factory narrow band and the wide band at the same time.. Then I'd set my Closed loop target AFR's a little richer for safety, force closed loop 100% of the time and disable WOT... I'd use the narrow band and fuel trims to verify what you are seeing with the AFR gauge... If you haven't changed the distance the O2 sensor is from the cylinder head (Exhaust runner length) then the factory O2 calibrations should be pretty solid... Even if you've put a header on the car, it shouldn't be to far out.. The import world doesn't run true long tube headers where the O2 transfer functions get screwed up.. (GM, Ford V8 world)... It's amazing what you can miss when you can't log the data, review it and group it together to see the averages..
If you have a cat on the car, you want to leave those tables stock otherwise you risk melting down the cat.. If you are running the car hard on the track.. Or if you live close to the mountains like me.. This is where those tables generally come into play.. You've leaned the car out quite a bit which increases cat temps.. If you do have a cat and plan to modify those tables.. take a temp gun with you and start physically checking the cat temp so you do push it to far..
Where I live, if you drive 2 hours outside of the city you do a slow climb up a mountain gaining about 2000 feet of elevation... This is the type of situation where you'll melt the cat down and get stranded with a plugged exhaust before you've finished the climb..
If I had to guess the 3d table helps determine the threshold(Where over temp enrichment is activated) and the 2d table works constantly in the back ground to calculate the temp as your driving..
I'd also get a second bung welded in so you can run the factory narrow band and the wide band at the same time.. Then I'd set my Closed loop target AFR's a little richer for safety, force closed loop 100% of the time and disable WOT... I'd use the narrow band and fuel trims to verify what you are seeing with the AFR gauge... If you haven't changed the distance the O2 sensor is from the cylinder head (Exhaust runner length) then the factory O2 calibrations should be pretty solid... Even if you've put a header on the car, it shouldn't be to far out.. The import world doesn't run true long tube headers where the O2 transfer functions get screwed up.. (GM, Ford V8 world)... It's amazing what you can miss when you can't log the data, review it and group it together to see the averages..
Re: Desired AFR going rich at high rpm
That is some useful information you have given me, I'll definitely give it a shot and see what I can do. I'll get the old O2 sensor welded back in within the next week and see how I go.
Do you recommend running 100% closed loop all the time because the issue is last time I tried to do that, my desired AFRs would stay at 14.7 when going WOT and didn't target spots on the table that where it should have. For example, the engine would be at 0.8 load and 4500RPM which on the Closed Loop table targets 13.2 but instead the car desires 14.7.
Do you recommend running 100% closed loop all the time because the issue is last time I tried to do that, my desired AFRs would stay at 14.7 when going WOT and didn't target spots on the table that where it should have. For example, the engine would be at 0.8 load and 4500RPM which on the Closed Loop table targets 13.2 but instead the car desires 14.7.
2007 Mazda 3 MPS | 219kw / 474nm @ wheels
-
CrazyCanadian
- Posts: 23
- Joined: July 4th, 2021, 8:32 pm
Re: Desired AFR going rich at high rpm
How did you disable WOT??
You've done a bunch of interesting things with your tune that I would change. You're VE table for example plays into the load calculation's/Torque calculations.. It also plays into the Fueling calculation.. This works with your MAF sensor..
I wouldn't run CL 100% of the time.. I would just use it as part of getting the airflow modeling sorted out... Once It's in a good range I would split to back to a more normal OL/CL setup..
You've done a bunch of interesting things with your tune that I would change. You're VE table for example plays into the load calculation's/Torque calculations.. It also plays into the Fueling calculation.. This works with your MAF sensor..
I wouldn't run CL 100% of the time.. I would just use it as part of getting the airflow modeling sorted out... Once It's in a good range I would split to back to a more normal OL/CL setup..