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I feel confused, but at the same time that you're confirming these initial thoughts:

I think the O2 sensor takes it's reading of the voltage from the middle of the sensor voltage range on my truck. I'm not the only user that has experienced that at 0.05 volts, I get the richest AFR's possible (12). Yet, at 0 volts, it equates to the truck running at 14.7 AFR. From 0.05 to 3.36 volts controls the O2 sensor from 12.01 - 14.6 AFR. Now I understand he has a narrow band sensor since he has his Bank1 high voltage set to 1.1 volts, but does the sensor follow the same weird wide band behavior described previously (this is a rhetorical question)?
So, in a way, you were telling the truck "everything is f..." BAM!
Whatever the case, I'm glad you can experience the boost without jerking around. Please attach your AEM FIC file so I can graph your fuel map. I want to see your fueling curve. :nerd
 

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Closing the loop (get it?) on the bucking/jerking, I finally 100% cured mine. Does anyone still read this thread? Probably not, but posting it for historical reference. I already identified that the 98 ECU doesn't like when the AEM FIC 6 "turns on" and starts modifying either the O2 sensor or the fuel injectors. I filled in all cells with data and that helped tremendously since there were no more 0 values but at around 3-4 lbs of boost the bucking would always return.

I found out that when the fuel values switched from a negative amount (I was pulling fuel at vacuum) to a positive amount, it would still at times calculate a "0" fuel value. Once it did it would buck until I gave it more throttle. I changed ALL of the cells to be a minimum of +0.8 and it's completely gone. It does mean my LTFT's are running at about -6% in vacuum, but that's not bad enough to cause any issues with my tune. Once it enters boost it's pretty close to a perfect 0 LTFT. Hoping this helps someone in the future.
 

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Thanks for posting the solution to the bucking mystery. If you hadn't dived down into the data (numbers; values) you probably wouldn't have ever figured out what was going on.
 

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Discussion Starter #24
Closing the loop (get it?) on the bucking/jerking, I finally 100% cured mine. Does anyone still read this thread? Probably not, but posting it for historical reference. I already identified that the 98 ECU doesn't like when the AEM FIC 6 "turns on" and starts modifying either the O2 sensor or the fuel injectors. I filled in all cells with data and that helped tremendously since there were no more 0 values but at around 3-4 lbs of boost the bucking would always return.

I found out that when the fuel values switched from a negative amount (I was pulling fuel at vacuum) to a positive amount, it would still at times calculate a "0" fuel value. Once it did it would buck until I gave it more throttle. I changed ALL of the cells to be a minimum of +0.8 and it's completely gone. It does mean my LTFT's are running at about -6% in vacuum, but that's not bad enough to cause any issues with my tune. Once it enters boost it's pretty close to a perfect 0 LTFT. Hoping this helps someone in the future.
I still lurk this forum, I am glad you posted this because I still have my bucking/jerking issue as well. When I filled in the whole o2 table it did help but never actually went away. Mine seems to only be right as vacuum turns into boost (0psi) at a freeway cruising speed, never has done it under acceleration. If I recall correctly my fuel table does start around 0-1psi so it may be because there is no AEM control while in vacuum. May have to try what you did as well and add values in vacuum.
 

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I still lurk this forum, I am glad you posted this because I still have my bucking/jerking issue as well. When I filled in the whole o2 table it did help but never actually went away. Mine seems to only be right as vacuum turns into boost (0psi) at a freeway cruising speed, never has done it under acceleration. If I recall correctly my fuel table does start around 0-1psi so it may be because there is no AEM control while in vacuum. May have to try what you did as well and add values in vacuum.
Yes, that's exactly how mine started since I initially had my fuel map the same way. Try just adding just the +0.8 to all cells and I'm confident it will go away.
 

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Yes, that's exactly how mine started since I initially had my fuel map the same way. Try just adding just the +0.8 to all cells and I'm confident it will go away.
I adjusted the fuel map last night and reset the memory so Ill give it a few weeks and see how she does!
 

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Wow. Praise to Gamefreakgc's efforts and results.

From an electrical stand point, I would hypothesis that maybe the AEM FIC "turning on" is creating a noise spike towards the Toyota ECU. Maybe.
 

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Hi Gamefreakgc.

I have a 2zr-swapped and turbo Yaris RS. I see that you offered to have a look at another member's cal file. I am wondering if you'd be willing to have a glace at mine. I have bucking and wild AFR fluctuations at around 3 - 4 psi under steady throttle position and load. If I press the throttle a little harder or back off, it stops. I have tried adjusting the fueling table in the areas that I get the bucking. I also experimented with 02 skewing. I used this video but any minute voltage inputs I make, result in the fuel trims jumping to -20, regardless of the voltage increment I enter. I just started inputting random voltage values (currently 2.6v in the segment f the map that is about 3 - 4 psi) and could get a nice fat AFR. If I use the basemap that comes with the turbo kit (turbokits-dot-com), I don't get the bucking, but my AFRs are a bit lean. I did have a tune done and it worked great on the dyno, but when cruising with the cruise control on, I get the bucking. Please let me know if you're willing to have a look. Maybe something will jump out at you. Thanks very much in advance. Adam

Here is the video I attempted to use: Wideband 02 Map AEM F/IC
 

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Hi, yes I can look at it if you're still having issues. I do have a few questions though first:

1. From what I've learned from Toyotas, most work on a 0-1V O2 sensor signal. Do you know if your Yaris has a narrowband or wideband and if it operates on a 0-1V or 0-5V signal? There are some inexpensive OBD-II data readers you can get off amazon for $40 or less that can read the raw O2 sensor data if you don't know.

2. Did the tuner use the MAF map or the O2 map for closed loop tuning?

3. What are your fueling sources? Bigger injectors, extra injectors, methanol, etc?

I think this forum still allows file attachments so just reply with the calibration file and I'll load it up and look at it.
 

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Hi, yes I can look at it if you're still having issues. I do have a few questions though first:

1. From what I've learned from Toyotas, most work on a 0-1V O2 sensor signal. Do you know if your Yaris has a narrowband or wideband and if it operates on a 0-1V or 0-5V signal? There are some inexpensive OBD-II data readers you can get off amazon for $40 or less that can read the raw O2 sensor data if you don't know.

2. Did the tuner use the MAF map or the O2 map for closed loop tuning?

3. What are your fueling sources? Bigger injectors, extra injectors, methanol, etc?

I think this forum still allows file attachments so just reply with the calibration file and I'll load it up and look at it.
Thanks very much! My Yaris has a wideband sensor in the downpipe and a narrow band downstream sensor. I have torque Pro (OBD2) on a 7" touchscreen and can see voltages for both pre-cat and post-cat sensors. The turbo kit came with a basemap. The basemap had no adjustments to the 02 map, just fueling, MAF (clamp) and timing. I am using the stock fuel pump, Deatschwerks 440 cc injectors and a DIY water injection system (running straight distilled water. Since installing the water injection, there have been no changes in the performance. The bucking occurred before the injection system and continues. When you open the cal file, you will see that I added 2.8 volts just inside the beginning of boost. This effectively brings my AFR into the high 11s. I think the problem might be in my fuel map. The tuner did not experience any bucking, but when I got out on the highway under moderate load in cruising (around 3 psi), it would buck. I temporarily fixed this by adding a little fuel in the active cell area. You will note some fairly large transitions between adjacent cells. I tried smoothing some of these out, but had little luck taming the occasional bucking. The cal I am sending you was tweaked a touch this morning (fuel map).

I really appreciate your looking at this for me. I wonder if there is a conflict between my 02 map and fuel map causing the issues. When I installed the original basemap that came with the kit, I had no bucking, but the AFRs seemed dangerously lean. The tuner added significant fuel throughout the map. My goal is to eliminate the bucking and wild AFR fluctuations. I hope it's something to do with the fuel map and 02 map not being in agreement.

Here are a couple of pics of my Torque setup. Car is at idle. Oddly the stock ECU has been commanding a slightly rich AFR for some time now.

135519

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This is the approximate area in which I get the bucking. It may extend a little outside of the boxed area. If it would be helpful, I could narrow it down a bit.

135521
 

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You might be experiencing the same problem I had when the FIC 6 switches from pulling fuel to adding fuel. That's the exact same transition area I had issues with. Most noticeable when I'd be on the freeway and would slowly accelerate, like to pass a vehicle, and it would start bucking on me. I'm willing to look at the rest of the map though.

Does your vehicle run if you zero out all the negative values? That's the easiest thing to try. Copy your .cal file (so you don't lose your original tune that you paid for) and then change every negative value to a 0.8% and if it'll run and drive, see if the bucking goes away. I ended up putting a 0.8% value because sometimes the 0's would also throw it off. By having a value of 0.8% the FIC is always modifying the signal so the ECU doesn't interfere with the signal since it's constant from startup.

If it won't start, try adding a delay timer. I have mine set to 25 seconds, which is about how long until I back out of a parking spot or out of my driveway when the engine is cold. If you are having issues getting it to run, you could set it to 120 seconds or longer to give it adequate time to switch to closed loop and then it'll apply the positive 0.8% fuel map.
 

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You might be experiencing the same problem I had when the FIC 6 switches from pulling fuel to adding fuel. That's the exact same transition area I had issues with. Most noticeable when I'd be on the freeway and would slowly accelerate, like to pass a vehicle, and it would start bucking on me. I'm willing to look at the rest of the map though.

Does your vehicle run if you zero out all the negative values? That's the easiest thing to try. Copy your .cal file (so you don't lose your original tune that you paid for) and then change every negative value to a 0.8% and if it'll run and drive, see if the bucking goes away. I ended up putting a 0.8% value because sometimes the 0's would also throw it off. By having a value of 0.8% the FIC is always modifying the signal so the ECU doesn't interfere with the signal since it's constant from startup.

If it won't start, try adding a delay timer. I have mine set to 25 seconds, which is about how long until I back out of a parking spot or out of my driveway when the engine is cold. If you are having issues getting it to run, you could set it to 120 seconds or longer to give it adequate time to switch to closed loop and then it'll apply the positive 0.8% fuel map.
The conditions you describe that cause the bucking are exactly the same as mine. I haven't tried changing all the negative values to 0.8 yet as I was concerned about running way too rich due to my over sized injectors. I can't recall what the stock Corolla injectors are, but I pretty sure that the 440cc injectors I have in there now are probably close to double what the stock ones put out. Did you put larger injectors in your vehicle? Where is the delay timer to which you refer? Is that the "Start Delay" in the 02 section of the Setup menu? I included a pic to be sure I was in the right area. I am also not certain which variables determine when my car goes from open loop to closed loop. I assumed it was either when the car was at operating temp or when the narrowband downstream 02 sensor became active. That's around 600 F, if I recall correctly. I think my actual stock wideband becomes active immediately upon start up.

Thanks very much for your willingness to help me out. I really appreciate it!

135523
 

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Looking back at the pic of the fuel map I posted in post #31, I think I put the red box a bit low. I don't seem to get any bucking when below 14.7 PSIA. That box should be moved up, maybe two rows. If it would be helpful, I could go for a run today and narrow down the exact area I get the bucking. Whatever you need, man. Thanks!
 

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Looking back at the pic of the fuel map I posted in post #31, I think I put the red box a bit low. I don't seem to get any bucking when below 14.7 PSIA. That box should be moved up, maybe two rows. If it would be helpful, I could go for a run today and narrow down the exact area I get the bucking. Whatever you need, man. Thanks!
Could you get a log of the actual bucking and import it into AEMLog? I was able to get one of mine, it wasn't too hard to do. If it's a very long file, could you zoom in to the affected area? If you don't have it or have never used it, it's a free online program by AEM. There's quick tutorials on how to use it as well, you'll just import your log files in the form of a text document and then open them.

The only values that would need to be graphed are Engine Load, Engine Speed, and Inj1%. I bet my bottom dollar it's happening once the fuel trim hits "0".

That's the start delay I mentioned but I forgot it does only affect the O2 sensor so that may not actually help anything. Please still try setting all values from a negative value to 0.8%. It won't kill your engine since it can run rich at startup without harming anything. I run 390cc injectors with an engine that came stock with 290cc injectors with no issues.

I plan on looking over your .fi6 file today.
 

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Could you get a log of the actual bucking and import it into AEMLog? I was able to get one of mine, it wasn't too hard to do. If it's a very long file, could you zoom in to the affected area? If you don't have it or have never used it, it's a free online program by AEM. There's quick tutorials on how to use it as well, you'll just import your log files in the form of a text document and then open them.

The only values that would need to be graphed are Engine Load, Engine Speed, and Inj1%. I bet my bottom dollar it's happening once the fuel trim hits "0".

That's the start delay I mentioned but I forgot it does only affect the O2 sensor so that may not actually help anything. Please still try setting all values from a negative value to 0.8%. It won't kill your engine since it can run rich at startup without harming anything. I run 390cc injectors with an engine that came stock with 290cc injectors with no issues.

I plan on looking over your .fi6 file today.
Thanks! This weekend, I'll data log the parameters you suggest. I have AEMLog already on my computer. So, just to be clear, you want me to change any negative fuel value in my fuel map to .8? I will try that too and post back.
 

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Here's some recommendations I have from the file:

1. I recommend changing the MAF table to "Percent" and not "Voltage" and 0 out all values. You had some values which were identical and some that were not meaning the FIC 6 was modifying the signal on one level in boost but not another and could cause issues.

2. Your O2 map is incomplete and very choppy. Did you do the entire process outlined in the video you mentioned here? Wideband O2 Control. If yes, you should have an voltage value for every AFR target. I see in one of your previous posts that the "Voltage" mode for the O2 map was not working and if you edit the value it goes bonkers. Switch it to "Offset" in the settings and try it again. You should end up with something like this written on a piece of paper or in an excel document:

-0.8V = 11.0 AFR 40STFT (short term fuel trim)
-0.4V = 12:5 AFR 30STFT
-.0.1V = 13.3 AFR 22STFT
0.6V = 17.0 AFR -30STFT

This is easier if you have a friend/spouse help you as one controls the values and the other records the data for the AFR and STFT. Then you click the "Show as AFR" option. Then enter the smallest voltage value at the top with the observed AFR and the largest voltage value at the bottom with observed AFR. Now, you can go to your O2 map and instead of having to tinker with voltages, you just enter in the AFR value you want and the FIC6 will automatically send the correct voltage skew. So instead of putting -0.1V in the cell value, you'd put 13.3 and that will create an AFR value of... 13.3. Easy. Then just set your maximum AFR value in your max boost in PSIA to 11.0 and the lowest enrichment value at 14.7 PSIA (normally around 13.5 to 14.5 AFRs, your preference) and fill in the rest in incremental drops. Can also use the Calculate function by right clicking a selection of a range of cells to have it do it for you. The ECU may not read the O2 sensor voltage once it hits open loop but having it there doesn't hurt, not having it there does. Trouble is you can never pinpoint what cells are in open loop and which are closed loop so best to fill it every cell 14.7 PSIA and above (if at elevation, adjust for your atmospheric pressure reading).

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That was a long explanation about O2 sensor skewing, I know. But it's vital to getting the tune drivable. Dyno tuning is great for pushing out max power but it's the tedious closed loop and partial boost tuning that makes it a good daily driver.

3. What is the max RPM it would ever see on your engine? Your fuel and ignition maps have a max RPM of 7000 but your O2 map has a max of 12000 RPM. Pretty sure unless you dropped a drag racing engine in it, you won't see 12000 RPM so the O2 map parameters needs to be changed to the same RPM values as the other tables otherwise it will be too hard to tune.

4. What is the max boost in PSIA that your vehicle would ever see? I see usable values on the fuel table up to 30 PSIA but the ignition map has a horrible value of -20 at 30PSIA. That should only be there if your engine never tops 28 PSIA. If it were to hit, say 29, it would take an average of -6 + -20 and split the difference, meaning it pulls -14 degrees of timing. Same goes with the bottom value of the fuel table, do you really want the ECU pulling -32% to -90% of all fuel at 0 PSIA? That should be the same value as the 2 PSIA row.

5. Your high RPM fuel table is weird. At 5250 RPM and 7 lbs of boost (22 PSIA) it adds +19.5% fuel. But at 15 lbs of boost (30 PSIA) it only adds +15.6 fuel??? Either you are terribly rich at 7 lbs or super lean at 15 lbs! Your tuner may have only tuned it for max boost and tried filling in the rest of the cells but they did a terrible job if that is the case.
 

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Wow! Thanks for the detailed suggestions. I greatly appreciate this! Before I dive into making changes, I will back up my current map. I'm guessing that you would recommend making all the changes you outlined before loading the map, as opposed to trying one adjustment, test driving and then adjusting another map?

1. MAF - MAF table is unchanged from the original file that came with the F/IC as far as I know. I pretty sure that my tuner did not touch it. My understanding is that it had to be clamped at 5v as the increased airflow would make the ECU go snakey if it exceeded 5v. If I change it to offset and zero out all the values, would the FIC then not be making any modifications to the MAF signal?

2. 02 - Yes, I tried the procedures outlined in the video. The problem was that no matter what value I put in (starting with 0.1v and then increasing increments of 1 decimal place), the fuel trims would go to -20 and the AFR would go to 17:1 (lean). In this case I was using Torque's OBD2 reading from the ECU. I then tried monitoring my dedicated wideband (aftermarket gauge) instead. It would show a very rich AFR of around 10:1. Definitely substantial disagreement between what OBD2 and the aftermarket gauge was telling me. The process in the video was a non-starter for me sadly. I had had such high hopes. The values that I entered (2.8v and 2.6v) were purely experimental. I just kept trying different values. I did achieve good AFRs at different boost levels. When it enters the 20 - 22.5 (at 2.8v) and 25 - 27.5 (2.6v), it drops to around 11.5. This, I am happy with, except for the bucking I get. This is why I suspected a conflict between my 02 and Fuel maps.

3. Max RPM. Since I have an automatic, when floored it will generally shift when it hits 6000 RPM. So, 6000 RPM, I would say, would represent the max. Indeed, when I looked at the maps I wondered why they did not follow the same axis values throughout all maps. Even the PSIA (y-axis) on the maps differ from one another.

4. Max boost - my max boost is currently right around 8 psi, so 22.7 PSIA. I actually live at sea level.

5. High RPM on table. Yeah, I don't understand why the values project so high. This kit is designed for a max boost of 8.6 psi, so I did wonder about that myself.

In summary I'm happy with my AFRs as I accelerate through the rpm and boost range, but it's the bucking at moderate boost/steady, partial throttle that detracts from the driving experience. I have learned to drive the car completely smoothly through specific throttle inputs, I actually mused about zeroing out my fuel map and just using 02 skewing. It seemed to me that it would be easier. Trick the ECU and have it add or subtract fuel based on the spoofed voltages.

The other issue I'm having, is that both cold starts, and starts after the engine has dropped from operating temps (after sitting for a while) are long. Currently, I might be looking at 6 - 8 seconds of cranking before it fires up. I sometimes smell gas when this happens. Only once some fuel actually dripped out under the car. It seems like it's flooding. I tried a few things: 1) holding the pedal to the floor as I thought it might cut the fuel. 2) adjusted the fuel map in the cranking area; reducing fuel. 3) turning the key on and waiting 5 - 10 seconds. I had heard that allowing the FIC to boot fully might help. After I installed 2.2Kohm resistor on the crank my cold starting issues totally disappeared but they have resurfaced. The hot start has always been an issue. If I shut the car off from operating temp for a short time (up to, say, 20 minutes), it will start immediately.

I am hoping to do some data logging this weekend or early in the week. I will log engine load, RPM and injector1 as you suggest. Do you think I should do that and provide the graphs to you before I make any changes; a baseline of sorts?

Thanks again!
 

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Wow! Thanks for the detailed suggestions. I greatly appreciate this! Before I dive into making changes, I will back up my current map. I'm guessing that you would recommend making all the changes you outlined before loading the map, as opposed to trying one adjustment, test driving and then adjusting another map?

1. MAF - MAF table is unchanged from the original file that came with the F/IC as far as I know. I pretty sure that my tuner did not touch it. My understanding is that it had to be clamped at 5v as the increased airflow would make the ECU go snakey if it exceeded 5v. If I change it to offset and zero out all the values, would the FIC then not be making any modifications to the MAF signal?

2. 02 - Yes, I tried the procedures outlined in the video. The problem was that no matter what value I put in (starting with 0.1v and then increasing increments of 1 decimal place), the fuel trims would go to -20 and the AFR would go to 17:1 (lean). In this case I was using Torque's OBD2 reading from the ECU. I then tried monitoring my dedicated wideband (aftermarket gauge) instead. It would show a very rich AFR of around 10:1. Definitely substantial disagreement between what OBD2 and the aftermarket gauge was telling me. The process in the video was a non-starter for me sadly. I had had such high hopes. The values that I entered (2.8v and 2.6v) were purely experimental. I just kept trying different values. I did achieve good AFRs at different boost levels. When it enters the 20 - 22.5 (at 2.8v) and 25 - 27.5 (2.6v), it drops to around 11.5. This, I am happy with, except for the bucking I get. This is why I suspected a conflict between my 02 and Fuel maps.

3. Max RPM. Since I have an automatic, when floored it will generally shift when it hits 6000 RPM. So, 6000 RPM, I would say, would represent the max. Indeed, when I looked at the maps I wondered why they did not follow the same axis values throughout all maps. Even the PSIA (y-axis) on the maps differ from one another.

4. Max boost - my max boost is currently right around 8 psi, so 22.7 PSIA. I actually live at sea level.

5. High RPM on table. Yeah, I don't understand why the values project so high. This kit is designed for a max boost of 8.6 psi, so I did wonder about that myself.

In summary I'm happy with my AFRs as I accelerate through the rpm and boost range, but it's the bucking at moderate boost/steady, partial throttle that detracts from the driving experience. I have learned to drive the car completely smoothly through specific throttle inputs, I actually mused about zeroing out my fuel map and just using 02 skewing. It seemed to me that it would be easier. Trick the ECU and have it add or subtract fuel based on the spoofed voltages.

The other issue I'm having, is that both cold starts, and starts after the engine has dropped from operating temps (after sitting for a while) are long. Currently, I might be looking at 6 - 8 seconds of cranking before it fires up. I sometimes smell gas when this happens. Only once some fuel actually dripped out under the car. It seems like it's flooding. I tried a few things: 1) holding the pedal to the floor as I thought it might cut the fuel. 2) adjusted the fuel map in the cranking area; reducing fuel. 3) turning the key on and waiting 5 - 10 seconds. I had heard that allowing the FIC to boot fully might help. After I installed 2.2Kohm resistor on the crank my cold starting issues totally disappeared but they have resurfaced. The hot start has always been an issue. If I shut the car off from operating temp for a short time (up to, say, 20 minutes), it will start immediately.

I am hoping to do some data logging this weekend or early in the week. I will log engine load, RPM and injector1 as you suggest. Do you think I should do that and provide the graphs to you before I make any changes; a baseline of sorts?

Thanks again!
1. The less maps you have active, the better the tune. Someone at some point put those MAF values in and can run better without them. The MAF clamp function is in the settings, it's set to 5 volts.

2. Wait, what you just described means it is working! You are FOOLING the ECU to think it's running lean to richen it up so of course the stock O2 sensor read by the ECU (from your OBD-II app) would read very lean but in reality, the wideband is showing very rich! Keep the O2 settings in Voltage mode then and your first value then is 0.1V - 10.0 AFR. Bump that to 0.2V, then 0.4V, then 0.6V etc. and record each reading.

3. Looks like you noticed this as well, tables just need edits then.

4. Sounds good. I was worried you were actually seeing high boosts and that explains the sloppy tune in the higher PSIA's.

5. Same as 4.

I agree, O2 sensor skewing is simpler on Toyotas than using MAF or Injector tuning since it's the O2 sensor that controls fueling in closed loop. If you can graph out your voltage and AFR values it'll be super simple to apply. Closed loop tuning on turbo'd vehicles is less important than on supercharged vehicles. Turbos only run at max PSI at full-throttle, which means if it's been dyno tuned it'll run pretty good as-is on the street. For supercharged vehicles they can hit max boost in overdrive passing on the freeway! I hit the upper cells in my map as low as 2250 RPM which makes tuning a real challenge.

A note on the long cranks, this is consistent with what I experienced the first 3 years I had mine installed as well. Then my engine blew so I replaced it with a lower mileage unit. Kept the wiring harness, ECU and AEM unit. With my "new" engine it never takes more than 1 second of cranking! So it seems just chance, some will crank for a long time, others will not and I could never solve that issue either.
 
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