Flex Fuel Woes

earlrengland

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I recently had PBD tune my car. I opted for the E85 tune as well, and as a bonus, was given a Flex Fuel tune, as they saw it as a 'novelty' tune. The 93 tune went very well, and since today, 04/29 has been one of the first days without rain, I got the car out. Seeing as the car sat for the Winter with a full tank of 93, I drove the tank down to about a quarter and then filled up with E85 and flashed the car with the FF tune. Not sure what it did, but I can barely drive the car now. It seemed fine for about the first 15 miles. Seemed smooth, but as soon as I hit the gas, the car bucked, and got a message on the dash that active exhaust was not available. I let off the pedal, and the car smoothed back out. I informed PDB about this, and they told me to do a KAM reset on the car, which I did. After the KAM reset, I took the car back out, and it was even worse! It dies at idle now, and along with bucking, it's now backfiring as well. I don't want to ruin the engine, but don't know what else to do. Has anyone else experienced this type of thing when going to Flex Fuel?

 

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Drain all the E85 out and fill it with 93, flash back to the 93 tune and see if that clears it up.
 
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earlrengland

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Is there an easy way to drain the tank? Never had to do that before.
 

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If you have E85 onboard skip the drain, and reflash. If you drain the tank, how do you get the station to refill, push the car?

as I think I understand FF is hypothetically speaking 50/50 alcohol & fossil, whereas E85 the alcohol has a larger % of alcohol.

"I opted for the E85 tune as well, and as a bonus, was given a Flex Fuel tune,"

What a bonus! and "novelty' tune." :question:

I'd be thinking stick with one or the other and it sure would not be a novelty, tune.

Tuners experiment gone bad, that's the problem with kids and computers..... too much what IFs and unwarranted self-esteem.

Should go back to them, with the problem it is their monkey.
 

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Ask them to give you a tune to drain the tank. If you have the fittings just make one with a hose to hook up to your feed line on your injector rail & drain it to a bucket.
 


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earlrengland

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I had seen so many others who were running a FF tune on the car, that seemed to do just fine. Agreed, not sure why it was labelled a 'novelty' tune, if other's like Lund do them all the time. Just frustrating, as up until the car was flashed with that tune, it ran just fine. I did let PDB know what was going on, but they fell silent after a few back and forths. Not bashing them by no means. I'm now wandering if I shouldn't just try flashing the car with the dedicated E85 tune they sent, seeing as it has over 3/4 of a tank of the stuff to see if that helps at all.
 

Radar Doc

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Sounds like the flex tune is not learning the fuel alcohol content properly. I would flash the E85 tune. Fuel trims will make up the difference in alcohol content until you can get more E85 in the tank. I wouldn't take the car to the track, but it should run better than it does now (assuming your E85 tune is good).

Is this an HP Tuners device? Are you equipped to datalog? If so, you can log these three parameters:
Inferred AFR Status: Reads Actively Learning, Paused or Matured.
Inferred AFR Source: Reads Refueling (after a refuel) or Fault Exit (after a flash or KAM reset)
Alcohol Percent

I'd log short and long fuel trims as well.

In addition to logging, for everyday monitoring I use a OBDLink MX+ device with an app on my phone for quick checks, KAM resets, alcohol content monitoring, etc. There are other OBD devices like this available as well. I highly recommend one of these if you're going to run E85 or flex tunes.
 

guzie

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I recently had PBD tune my car. I opted for the E85 tune as well, and as a bonus, was given a Flex Fuel tune, as they saw it as a 'novelty' tune. The 93 tune went very well, and since today, 04/29 has been one of the first days without rain, I got the car out. Seeing as the car sat for the Winter with a full tank of 93, I drove the tank down to about a quarter and then filled up with E85 and flashed the car with the FF tune. Not sure what it did, but I can barely drive the car now. It seemed fine for about the first 15 miles. Seemed smooth, but as soon as I hit the gas, the car bucked, and got a message on the dash that active exhaust was not available. I let off the pedal, and the car smoothed back out. I informed PDB about this, and they told me to do a KAM reset on the car, which I did. After the KAM reset, I took the car back out, and it was even worse! It dies at idle now, and along with bucking, it's now backfiring as well. I don't want to ruin the engine, but don't know what else to do. Has anyone else experienced this type of thing when going to Flex Fuel?
Did you datalog the 93 tune properly and get that dialed in with them first? After that you need to get the 93 octane down to where your pretty much empty before doing E85 in the tank. You then load the E85 tune and put E85 in the tank to run through a series of logs to dial it in. The flex tune is really only for those transitions for one fuel type to the other and its still best to get as much out as possible and not do 1/4-1/2 tank blends. There is not a true ethanol sensor. Ford uses data from the widebands and data tables in the ecu to guesstimate where the fuel is at in the way of ethanol percentage. They do that strategy in the F150 from the factory which Lund capitalized one with the first S550 that came out. It’s not a novelty but I would not push the car as hard running a flex tune vs the 93 or straight E85. The flex tune does not have the same timing advance as the E85 tune because it’s not guaranteed To be a full tank of higher octane E85. I have run Lund tunes on both my Gt350s and to great success with zero issues. The only issue I ran into was my 2018 GT350 had its ngauge from Lund crap out as I took it out of storage. I used the ngauge to quickly switch tunes and I’m stuck in 93 tune with it. I eded up getting a SCT tuner and will be doing the PBD 93 tune and E85 tune next week as I just got done putting long tubes on it and I’m ready for tuning and data logging.
 
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earlrengland

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Sounds like the flex tune is not learning the fuel alcohol content properly. I would flash the E85 tune. Fuel trims will make up the difference in alcohol content until you can get more E85 in the tank. I wouldn't take the car to the track, but it should run better than it does now (assuming your E85 tune is good).

Is this an HP Tuners device? Are you equipped to datalog? If so, you can log these three parameters:
Inferred AFR Status: Reads Actively Learning, Paused or Matured.
Inferred AFR Source: Reads Refueling (after a refuel) or Fault Exit (after a flash or KAM reset)
Alcohol Percent

I'd log short and long fuel trims as well.

In addition to logging, for everyday monitoring I use a OBDLink MX+ device with an app on my phone for quick checks, KAM resets, alcohol content monitoring, etc. There are other OBD devices like this available as well. I highly recommend one of these if you're going to run E85 or flex tunes.
I'm using an SCT X4 tuner.
 
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earlrengland

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Did you datalog the 93 tune properly and get that dialed in with them first? After that you need to get the 93 octane down to where your pretty much empty before doing E85 in the tank. You then load the E85 tune and put E85 in the tank to run through a series of logs to dial it in. The flex tune is really only for those transitions for one fuel type to the other and its still best to get as much out as possible and not do 1/4-1/2 tank blends. There is not a true ethanol sensor. Ford uses data from the widebands and data tables in the ecu to guesstimate where the fuel is at in the way of ethanol percentage. They do that strategy in the F150 from the factory which Lund capitalized one with the first S550 that came out. It’s not a novelty but I would not push the car as hard running a flex tune vs the 93 or straight E85. The flex tune does not have the same timing advance as the E85 tune because it’s not guaranteed To be a full tank of higher octane E85. I have run Lund tunes on both my Gt350s and to great success with zero issues. The only issue I ran into was my 2018 GT350 had its ngauge from Lund crap out as I took it out of storage. I used the ngauge to quickly switch tunes and I’m stuck in 93 tune with it. I eded up getting a SCT tuner and will be doing the PBD 93 tune and E85 tune next week as I just got done putting long tubes on it and I’m ready for tuning and data logging.
I think that was my mistake. I did do proper logs for the 93 tune, and PDB told me it was good to go. The FF tune they sent me, I'm told, was based on that 93 tune, and that no further logs were needed, which in my mind, meant I could flash the car with the FF tune, put E in the car, and run it, which I did. I do understand the need to bring the tank down as much as possible, but the car still had over a half tank of 93 in it, and with the weather up here, yesterday was the first day I could get the car out and drive. So me, thinking I didn't want to drive all day to run it out of gas, thought I'll run it down below a quarter tank, fill it up with E, flash the car with the FF tune, and drive without issue, since PDB told me I was pretty much set. This is my first experience with E85, after hearing all kinds of great things about it, but maybe I jumped the gun, expecting the car to run like a raped ape after putting it in. Right now, I my hope is to just get the car to run period.
 

Radar Doc

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Well, you can monitor short and long term fuel trims with the X4. If the flex tune thinks you're on 93 (or low alcohol content), your STFTs and LTFTs will be greater than 1.0 as the computer adds more fuel in an attempt to compensate. If you flash the E85 tune, I would expect the numbers to still be above 1.0, but closer to 1.0. The car should run much better.
 
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earlrengland

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Well, you can monitor short and long term fuel trims with the X4. If the flex tune thinks you're on 93 (or low alcohol content), your STFTs and LTFTs will be greater than 1.0 as the computer adds more fuel in an attempt to compensate. If you flash the E85 tune, I would expect the numbers to still be above 1.0, but closer to 1.0. The car should run much better.
I'll give that a shot. Thanks for the advise!
 

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And one correction to what I said, I would expect the fuel trims to be under 1.0 after you flash the E85 tune. Assuming you have about 66% ethanol at the moment, the computer will actually be pulling some fuel to maintain stoich.
 
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earlrengland

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Reflashed the car with the dedicated E85 tune, and it runs ALOT better! I was a little hesitant to flash it, since I still had some 93 in the tank, but it didn't seem to matter. Huge improvement! Thanks to everyone for the suggestions.
 

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I recommend testing your fuel with a test kit if you’re running the dedicated E85 tune, otherwise, I’m not sure it’s safe to be going WOT on the dedicated tune with more aggressive timing If your ethanol content is too low. Maybe run that tank out on the dedicated tune without going WOT and then switch back to the flex tune. My car lives on the flex tune because it’s Always hit or miss finding E85 with 80% or higher ethanol at the pump.
 

 
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