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Has anyone had a detonation issues following the flex fuel mod and tune? A very reputable SoCal shop that everyone would recognize advised against flex fuel and tune because they do not believe any existing products effectively detect ethanol content and then properly adjust timing in real time. They basically said the tune will be optimized for the gas in the tank at the time of the tune which will result in detonation issues when e content drops or premium unleaded is used. Thoughts?
I ran a custom dyno tune (for 93) with AFD flex E85 kit and it was having a slight hickup when you WOT floor it. Had it on full E85 for 300 miles. It was doing it with 17% to 75% ethanol (E85 here only has 75ish %). But I had no fuel pressure codes because I have upgraded AEM E85 fuel pumps. My tuner says it was the flex kit and that I need to bring it in for an E85 custom tune. He thinks it was running rich at the moment I WOT. So I went back to 93 and havent really noticed the hiccup. Not really sure if it will do it on a stock tune. I havent had the chance to go back and get my tune because my RADTEC oil cooler started leaking after only 4 months of use (Radtec said they will send me a new one asap).. separate story. I will also pickup my handheld tuner so I can switch between 3 maps - stock, custom 93, custom E85. I also have the FAMS tune so I might try the E85 on that tune just to see. Having the E85 in the tank definitely made the m5 pull harder for sure.
 

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Hmmm... I should see if I can get a hold of Jim @ FAMS to update my tune to add E85 as an option (just in case).
 

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Has anyone had a detonation issues following the flex fuel mod and tune? A very reputable SoCal shop that everyone would recognize advised against flex fuel and tune because they do not believe any existing products effectively detect ethanol content and then properly adjust timing in real time. They basically said the tune will be optimized for the gas in the tank at the time of the tune which will result in detonation issues when e content drops or premium unleaded is used. Thoughts?
There is a difference between this AFD ethanol piggyback system and an actual E85 specific tune. The AFD system uses sensors to compensate for the ethanol content of the fuel you're using regardless of whether it is 0% ethanol or 90% ethanol. The flexfuel system will not give you the full benefit power-wise of a custom E85 tune as you would just be running whatever your stock/aftermarket tune is with higher octane fuel. You will still get some more power by using an ethanol mix with the AFD system as the octane rating will/should be higher than 93 octane and you hypothetically do not have to worry about the ethanol content as the AFD system will adjust based on what the E content of your fuel is. If you do get a custom E85 tune where you have been tuned specifically on/for E85 then you will presumably only be able to fuel up with E85 (or whatever the mix your car is tuned for) as using lower octane/less E85 fuel would cause issues. I have the AFD system installed but unfortunately have had some issues so hopefully someone here who knows more than me can help out.

I had the AFD flexfuel kit installed by my local indy shop (as well as a new filter and duel AEM pumps) and managed to connect to the app initially which showed the 93 octane that was already in my gas tank as E10 or so. I drove until the tank was almost empty and went to go fill up with E from the gas station by my house. At this point I did not yet have an E tester and did not test the E content at the pump. I filled up at the E pump and drove the half a mile or so back home without issue. I kept an eye on the E content as it went up after filling up to about E75 once I got home. I came back out to the car an hour or so later and immediately upon starting up I got misfire codes for one entire bank of cylinders and could no longer get a reading from the ethanol sensor. I took the car back to the shop where they took a look and said I had put bad fuel in the tank and that it had come out discolored (red-ish) when they drained it. They filled it back up with 93 and the misfire issue went away. After that I was never able to get the app to connect to the bluetooth sensor again. I got in touch with Gray at AFD and walked him through what had happened. He said that if I had put bad E in the car that would explain the misfire but the sensor not connecting to my phone was not related and the system should still work whether I can connect or not. He agreed to have me mail back the two brains to the system to test them out and he let me know that one of them was not working properly and they replaced it then sent them back (want to take a second here to note that Gray and the folks at AFD were super helpful to the extent that they could be in answering my questions and taking the brains back to fix them without any issues). When re-installed the brains I still cant manage to get my phone to connect to the sensor and have been stuck at that point for the past year or so and have kind of given up figuring it out (until this thread popped back up). So I am hoping someone can identify what might be wrong. To sum up my questions related to this:
  1. Has anyone with the AFD system been able to run ethanol with the bluetooth connection not working for the sensor? AFD says it should work whether the sensor is communicating with the bluetooth app or not but i'm not sure that is the only issue that I have.
  2. Is it possible that the ethanol that I originally put in that caused the misfire caused some damage/issue with the sensor that has affected the system? is it possible that my gas tank just had a bunch of gunk/filth in it from the past 14 years and the ethanol dislodged it causing the issue? the only reason I am wondering is the sensor seemed to indicate that the Ethanol was 75%+ so i'm not sure if the issue was actually with my car and not the fuel.
  3. Not sure how else to troubleshoot to ensure that the system works without filling it up with Ethanol again and trying it out. The problems I have with that are that it still does not identify the problem with the sensor communicating or with what was originally causing the misfire. I also have since gotten a FAMS tune on 93...I apologize for the possibly stupid question but I should be able to run E85 (assuming a functioning FlexFuel kit) with a 93 tune as the fuel would just be a higher octane so it should not cause knock or timing issues?
I guess my issue is that I don't just want to pump more E into the car if I have no way of knowing that the flexfuel system is actually functioning fully/properly as well as without being sure that I can run E85 on my 93 octane tune without causing any other engine/fueling problems. If anyone has had any of these sorts of issues with their system your help would be much appreciated. After I had followed up with the folks at AFD they said that it may be some other part of my car that is causing the failure but i'm not sure what it could be.
 

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There is a difference between this AFD ethanol piggyback system and an actual E85 specific tune. The AFD system uses sensors to compensate for the ethanol content of the fuel you're using regardless of whether it is 0% ethanol or 90% ethanol. The flexfuel system will not give you the full benefit power-wise of a custom E85 tune as you would just be running whatever your stock/aftermarket tune is with higher octane fuel. You will still get some more power by using an ethanol mix with the AFD system as the octane rating will/should be higher than 93 octane and you hypothetically do not have to worry about the ethanol content as the AFD system will adjust based on what the E content of your fuel is. If you do get a custom E85 tune where you have been tuned specifically on/for E85 then you will presumably only be able to fuel up with E85 (or whatever the mix your car is tuned for) as using lower octane/less E85 fuel would cause issues. I have the AFD system installed but unfortunately have had some issues so hopefully someone here who knows more than me can help out.

I had the AFD flexfuel kit installed by my local indy shop (as well as a new filter and duel AEM pumps) and managed to connect to the app initially which showed the 93 octane that was already in my gas tank as E10 or so. I drove until the tank was almost empty and went to go fill up with E from the gas station by my house. At this point I did not yet have an E tester and did not test the E content at the pump. I filled up at the E pump and drove the half a mile or so back home without issue. I kept an eye on the E content as it went up after filling up to about E75 once I got home. I came back out to the car an hour or so later and immediately upon starting up I got misfire codes for one entire bank of cylinders and could no longer get a reading from the ethanol sensor. I took the car back to the shop where they took a look and said I had put bad fuel in the tank and that it had come out discolored (red-ish) when they drained it. They filled it back up with 93 and the misfire issue went away. After that I was never able to get the app to connect to the bluetooth sensor again. I got in touch with Gray at AFD and walked him through what had happened. He said that if I had put bad E in the car that would explain the misfire but the sensor not connecting to my phone was not related and the system should still work whether I can connect or not. He agreed to have me mail back the two brains to the system to test them out and he let me know that one of them was not working properly and they replaced it then sent them back (want to take a second here to note that Gray and the folks at AFD were super helpful to the extent that they could be in answering my questions and taking the brains back to fix them without any issues). When re-installed the brains I still cant manage to get my phone to connect to the sensor and have been stuck at that point for the past year or so and have kind of given up figuring it out (until this thread popped back up). So I am hoping someone can identify what might be wrong. To sum up my questions related to this:
  1. Has anyone with the AFD system been able to run ethanol with the bluetooth connection not working for the sensor? AFD says it should work whether the sensor is communicating with the bluetooth app or not but i'm not sure that is the only issue that I have.
  2. Is it possible that the ethanol that I originally put in that caused the misfire caused some damage/issue with the sensor that has affected the system? is it possible that my gas tank just had a bunch of gunk/filth in it from the past 14 years and the ethanol dislodged it causing the issue? the only reason I am wondering is the sensor seemed to indicate that the Ethanol was 75%+ so i'm not sure if the issue was actually with my car and not the fuel.
  3. Not sure how else to troubleshoot to ensure that the system works without filling it up with Ethanol again and trying it out. The problems I have with that are that it still does not identify the problem with the sensor communicating or with what was originally causing the misfire. I also have since gotten a FAMS tune on 93...I apologize for the possibly stupid question but I should be able to run E85 (assuming a functioning FlexFuel kit) with a 93 tune as the fuel would just be a higher octane so it should not cause knock or timing issues?
I guess my issue is that I don't just want to pump more E into the car if I have no way of knowing that the flexfuel system is actually functioning fully/properly as well as without being sure that I can run E85 on my 93 octane tune without causing any other engine/fueling problems. If anyone has had any of these sorts of issues with their system your help would be much appreciated. After I had followed up with the folks at AFD they said that it may be some other part of my car that is causing the failure but i'm not sure what it could be.
I was running AFD on E85 @ 75% Ethanol content with my custom dyno tune for 93. Like my previous response the only issue I have experienced is that when I floor it to WOT from steady 3800 - 4200, I get a "hiccup". My tuner suspects its the AFD that causes that hiccup - possibly goes too rich after flooring it to WOT. Other than that, the app worked flawlessly. If it acted up I just restart the engine. It definitely pulled harder for sure and I never got any errors. I also have dual AEM fuel pumps and got 6 - 8mpg with the way I drove.

I burned the E85 in the tank and went back to full 93. So far I havent had that hiccup issue. I need to test some more to be fully sure it wasnt the custom tune causing that hiccup. Car is on jack stands right now cuz Im waiting for my RPI cooler. After I get that swapped, will be testing for that hiccup some more. After thats confirmed I will fill it up with E85 again and go back to the dyno shop to get dynoed for custom E85 tune.

I suspect your GM fuel sensor, the one you tap into the gas line is defective. I ran mine with the brains unplugged after installing the system. After running it with no errors, then I plugged the brains, filled up with E and had fun.
 

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That makes sense since I did run bad fuel through it. Thanks for the advice. Luckily the sensor itself doesnt seem to expensive so hopefully that fixes it. My only concern is the app stays on the black "connecting" screen but if it is the sensor I imagine that's because the brains aren't getting a signal from it or something.
 
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