Hi Tacit Tacet, We received some help with this question from AEM. This is an extensive response. We will also private message you with the entire response as well as a link to the forum for further discussion. Thank you for watching! : The AEM F/IC is considered a piggyback system, and in some cases must “trick” the stock ECU to allow the vehicle to be tuned correctly. This is important to remember especially when dealing with the stock O2 sensors in the vehicle.
The above reason is why the chart shows a positive STFT accompanying a rich AFR. The end goal is to end up with an actual measured AFR that’s richer than 14.7 as you want, but a fuel trim close to 0, because the ECU is not detecting the rich condition due to your adjustments made to the O2 sensor. If you have any further F/IC tuning questions, I’d suggest the F/IC section of the AEM forums, which I have linked to below.
If you simply go into the fuel map in the F/IC and add fuel, the fuel trims will compensate and pull it right back out. This is where “tricking” the ECU is useful. You want to trick the ECU into thinking it’s running too lean, so that the ECU itself adds the fuel for you which will cause the engine to run richer, and you will also see a positive fuel trim (since the ECU thinks the engine is actually too lean, when it’s really not).You can help along this process by adding fuel to the fuel map.
The difference in the video’s case is that we’re actually tricking the stock ECU into thinking it’s running at a different AFR than it actually is. For instance, when adding forced induction to a normally naturally aspirated vehicle, there’s usually an area in the transitional period from vacuum to boost where the car is still in closed-loop, so the stock ECU is trying to keep the car near 14.7 AFR for emissions, but you’re actually starting to get into boost, and 14.7 may be too lean for that.
In the “Wideband O2 Map” video, the chart you’re referencing, which shows O2 Voltage, AFR Target, and STFT, you see that the STFT becomes increasingly negative as the measured AFR becomes leaner. On the face of it, this seems counterintuitive or inverted. Anyone who’s familiar with stock ECU fuel trims knows that a car that’s too rich will show as a negative fuel trim (STFT).
The map also shows upto 44 and down to -32 under STFT... Is this in percent ??? I thought that STFT was only able to regulate +- 25% and if it had to wander off this much then the LTFT would be adjusted accordenly, or it would just enter a fail safe limp home mode
Is the map at 3:22 not inverted... The STFT goes negative when the engine leans out.. so it's a runaway senario --> If the engine is running lean, then the algorithm tries to compensate, but in the wrong direction thus resulting in the engine running even more lean... and round and round we go ... It's viceversa at the rich end of the map..
This is unlikely to get answered as the video is old but I'd sure like some help. I tried the procedure and no matter what voltage value I put into the 02 map, I get a STFT of around +20. The AFR displayed by my OBD tool (Torque Pro) always shows 17 no matter what voltage I enter. I also have a dedicated wideband (Bosch LSU 4.9) and it will show fluctuations in AFR with different voltages. I tried different voltage values in the 02 map to experiment. I got wild fluctuations in AFR and bucking during the onset of boost. So, I'm basically stuck at step one of this tutorial. I am using a basemap from the turbo kit that I bought. Obviously, my fuel values are not set at "0" in the map. Does this process account for upgraded (upsized) fuel injectors? Do I have to start with all zeros in my fuel map. I would like to start with a brand new map (tables all zeros, but I'm afraid my car wouldn't even run if I did that. I was optimistic that this would work, but all it has turned out to be is frustrating. Help please! If anyone is around to help me.
Adam B. I hadn’t realized it before, that your stock O2 sensor was reading 17 constantly on torque. Mine always runs very close to my dedicated wide band. Once I figure the O2 map out as the videos results, I anticipate the torque AFR to be closer to stoich, as it comes from the ecu, which we’re tricking, and the WB to be closer to target. I’m also wondering if my earlier efforts to create the v/AFR/stft table were hampered by the vacuum leak I fixed the other night. On the fuel map question, if you are generally happy with the map currently, I would probably just change values in the regions needed by the stft value from the table created...once created 🙂
@@FishHawk1 Thanks man! My Torque only showed 17 when at idle and when I entered any voltage value. If no voltage value was entered in the O2 map, my AFR in Torque closely matched my dedicated wideband. My baby is in storage now, but I'll definitely be doing some more tweaking in the spring. Right now I just have a few rows filled with some voltage inputs in the low to mid, partial throttle boost range.
If you can read the fuel trims I dont see why not. Most data readers that can read STFT and LTFT are expensive and need an external power source. This means that it will most likely need to be a dyno tune.
Hi Tacit Tacet, We received some help with this question from AEM. This is an extensive response. We will also private message you with the entire response as well as a link to the forum for further discussion. Thank you for watching! : The AEM F/IC is considered a piggyback system, and in some cases must “trick” the stock ECU to allow the vehicle to be tuned correctly. This is important to remember especially when dealing with the stock O2 sensors in the vehicle.
The above reason is why the chart shows a positive STFT accompanying a rich AFR. The end goal is to end up with an actual measured AFR that’s richer than 14.7 as you want, but a fuel trim close to 0, because the ECU is not detecting the rich condition due to your adjustments made to the O2 sensor. If you have any further F/IC tuning questions, I’d suggest the F/IC section of the AEM forums, which I have linked to below.
If you simply go into the fuel map in the F/IC and add fuel, the fuel trims will compensate and pull it right back out. This is where “tricking” the ECU is useful. You want to trick the ECU into thinking it’s running too lean, so that the ECU itself adds the fuel for you which will cause the engine to run richer, and you will also see a positive fuel trim (since the ECU thinks the engine is actually too lean, when it’s really not).You can help along this process by adding fuel to the fuel map.
The difference in the video’s case is that we’re actually tricking the stock ECU into thinking it’s running at a different AFR than it actually is. For instance, when adding forced induction to a normally naturally aspirated vehicle, there’s usually an area in the transitional period from vacuum to boost where the car is still in closed-loop, so the stock ECU is trying to keep the car near 14.7 AFR for emissions, but you’re actually starting to get into boost, and 14.7 may be too lean for that.
In the “Wideband O2 Map” video, the chart you’re referencing, which shows O2 Voltage, AFR Target, and STFT, you see that the STFT becomes increasingly negative as the measured AFR becomes leaner. On the face of it, this seems counterintuitive or inverted. Anyone who’s familiar with stock ECU fuel trims knows that a car that’s too rich will show as a negative fuel trim (STFT).
The map also shows upto 44 and down to -32 under STFT... Is this in percent ??? I thought that STFT was only able to regulate +- 25% and if it had to wander off this much then the LTFT would be adjusted accordenly, or it would just enter a fail safe limp home mode
Is the map at 3:22 not inverted...
The STFT goes negative when the engine leans out.. so it's a runaway senario -->
If the engine is running lean, then the algorithm tries to compensate, but in the wrong direction thus resulting in the engine running even more lean... and round and round we go ...
It's viceversa at the rich end of the map..
This is unlikely to get answered as the video is old but I'd sure like some help. I tried the procedure and no matter what voltage value I put into the 02 map, I get a STFT of around +20. The AFR displayed by my OBD tool (Torque Pro) always shows 17 no matter what voltage I enter. I also have a dedicated wideband (Bosch LSU 4.9) and it will show fluctuations in AFR with different voltages. I tried different voltage values in the 02 map to experiment. I got wild fluctuations in AFR and bucking during the onset of boost. So, I'm basically stuck at step one of this tutorial. I am using a basemap from the turbo kit that I bought. Obviously, my fuel values are not set at "0" in the map. Does this process account for upgraded (upsized) fuel injectors? Do I have to start with all zeros in my fuel map. I would like to start with a brand new map (tables all zeros, but I'm afraid my car wouldn't even run if I did that. I was optimistic that this would work, but all it has turned out to be is frustrating. Help please! If anyone is around to help me.
Adam B. I hadn’t realized it before, that your stock O2 sensor was reading 17 constantly on torque. Mine always runs very close to my dedicated wide band. Once I figure the O2 map out as the videos results, I anticipate the torque AFR to be closer to stoich, as it comes from the ecu, which we’re tricking, and the WB to be closer to target. I’m also wondering if my earlier efforts to create the v/AFR/stft table were hampered by the vacuum leak I fixed the other night. On the fuel map question, if you are generally happy with the map currently, I would probably just change values in the regions needed by the stft value from the table created...once created 🙂
@@FishHawk1 Thanks man! My Torque only showed 17 when at idle and when I entered any voltage value. If no voltage value was entered in the O2 map, my AFR in Torque closely matched my dedicated wideband. My baby is in storage now, but I'll definitely be doing some more tweaking in the spring. Right now I just have a few rows filled with some voltage inputs in the low to mid, partial throttle boost range.
@@acbent11 兄弟 您的问题解决了吗
Will this unit work for OBD 1 Pre 1996 vehicles? IE 1992 Mitsubishi mighty max pickup truck thanks.
If you can read the fuel trims I dont see why not. Most data readers that can read STFT and LTFT are expensive and need an external power source. This means that it will most likely need to be a dyno tune.
Dear sir thank you training online TH-cam