Flex fuel tune check engine

[Junkyard Dog]

Who is doing a proper flex fuel tune?

That is a very good question.

Follow up questions would be, how do we know it is "proper" and what is a flex fuel sensor? You might be able to come up with a few more important questions after you have answers to those two.

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[Junkyard Dog]

 

[ChitownStang]

Who is doing a proper flex fuel tune?

DRP, Jugernaut, Palm Beach.
It seems like many of them offer a E30, E50, E85 as the second fuel.
I think that means Flex but it's confusing.
Palm Beach doesn't advertise Flex but when I call them they say they do it.

 

[Garcia172]

DRP, Jugernaut, Palm Beach.
It seems like many of them offer a E30, E50, E85 as the second fuel.
I think that means Flex but it's confusing.
Palm Beach doesn't advertise Flex but when I call them they say they do it.

Is this a true flex fuel (meaning... adjusting between two maps depending on the quantity of ethanol present) or switching (black & white) between two maps (somehow switching the maps back and forth)?

 

[ChitownStang]

Is this a true flex fuel (meaning... adjusting between two maps depending on the quantity of ethanol present) or switching (black & white) between two maps (somehow switching the maps back and forth)?

Here is a video of DRP explaining in depth.

 

[Junkyard Dog]

It seems like many of them offer a E30, E50, E85 as the second fuel.
I think that means Flex but it's confusing.

That does not mean flex fuel at all.

Flex fuel has an alcohol sensor and trims the fuel instantly based on the alcohol level in the fuel, sensed as it passes over the sensor.

Tunes for E30, E50, and E85 are just that, three tunes for different levels of alcohol.

A true flex fuel tune would adjust no matter what level the E85 is, and it would adjust instantly. Have a quarter tank of 93 left but want to fill up the rest with E85? No problem. The tune simply adjusts for whatever alcohol level is present in the fuel line.

I had an Audi and a GM Denali that were flex fuel. You could put either E85 or 93 in them no matter what was in there before or how much was left in the tank with no worries about whether it would run correctly and no need to change anything about the tune.

As pointed out above, this requires an ethanol sensor.

 

[Junkyard Dog]

Here is a video of DRP explaining in depth.

Note the "slow to adjust" comment and they do not recommend it for forced induction.

This tells me all I need to know.

They are not using a flex fuel sensor for some reason.

The car struggles to run until it figures out a good ratio to use. See after 5 minutes or so in the video. That is not how flex fuel setups with a flex fuel sensor run. You never know anything about the alcohol level changing. The engine adjusts instantly.

It sounds like this tune is meant for naturally aspirated cars running on E85. It is a safety net in case you cannot find E85. It is nothing like the flex fuel GM has offered on its trucks for almost two decades and nothing like the flex fuel on my turbocharged Audi.


But that does not mean it is not useful. I would much rather have this tune than a pure E85 tune and be caught in an area with no E85 available.

 

[ChitownStang]

Note the "slow to adjust" comment and they do not recommend it for forced induction.

This tells me all I need to know.

They are not using a flex fuel sensor for some reason.

All flex fuel tunes I used on my Mach 1 in past had no sensor. Just fill up tank to trigger learning and drive nice for 15 miles or so.
I had Livernois and Wengerd. Both worked perfectly every-time I filled up.
You just can’t switch fuels and go red lining it like I’m sure a lot of foolish people did which causes problems for tuners

 

[DarkMatterGrey]

This is why I won’t get a tune on my late 2023 S650 GT, which is a daily:

A) it’s a 6 speed manual, so no concomitant benefit of transmission tuning except for what I can do electronically (rev matching [which I do use], driving mode [sport is my favorite thus far], launch mode [haven’t even tried that yet]. Thankfully at least I have a Job 1 with no start/stop.

B) I’m 62 years old But seriously, I haven’t gone much beyond 5 grand with this car. Love the sounds this car makes, but not into street roll racing although I do get goaded a lot.

C) Most importantly, fuel availability in Arizona is horrible. Our gas is predominantly the California, Arizona, Nevada (CAN) network so we’re limited on options. Costco carries only 87 and 91 (assuming E10), which is at least top tier. Other stations carry 89, which I’m assuming is 87/91 blend. Very few stations carry “E85”, which isn’t per:

https://agriculture.az.gov/sites/default/files/Dispenser Labeling in Arizona 09.18.2023.pdf

Our E85 is between 51 and 83 so trying to make E30, E50, or rely on E85 is near impossible. A couple of stations, thankfully one of which is near me, not only carry 95 ($9 per gal) and 100 ($10 per gal) at the pump (which I believe is Sunoco 260 E10), but also have various Sunoco race gas options by the can. I inquired about E85, which is $109 for 5 gal. So my best cost/availability option is making 93 from their 100 and Costco 91 (I try to always stay north of that with a little extra 100). My assumption is that going with higher octane (94-100) without a tune won’t make much more power than the stock tuning just running 93, but if I need to road trip, which I have, I’ll just fill up with 91 and run the risk of the stock tune pulling some timing until I can run it again on my hand blended 93+.

I’ve talked with a lot of folks at car shows about this CAN gas and limited availability of E problem. Most didn’t know this. Some are even running an E85 tune with pump fake E85.

 

[ZXMustang]

Nobody uses a real e content sensor. It’s all inferred from the widebands/fuel trims. And junkyard, the car has real time fuel trims anyway and can add or subtract 35% as needed safely. It’s not ideal but it’s fine for varying blends. It’s easier to just change the stoich to whatever is needed for that fuel manually. The flex tunes are meh with the mustangs. They are exactly as Derp said slow to change.

 

[Junkyard Dog]

Nobody uses a real e content sensor.

I do not understand this comment. General Motors does. This is not like, my opinion, man.

Audi used to offer some models with flex fuel, using a sensor. I owned one. Google tells me that they do not sell any in the American market today.

 

[ZXMustang]

I do not understand this comment. General Motors does. This is not like, my opinion, man.

Audi used to offer some models with flex fuel, using a sensor. I owned one. Google tells me that they do not sell any in the American market today.

I meant with mustangs. You said you were guessing that a real e content sensor wasn’t being used and this was correct because as I said , nobody uses them. Not on mustangs. They can’t be pinned in like on GM cars. Yes I’ve tuned several Camaros with the real e sensor added and the PCM will get real time data on the ethanol content. That’s not possible with the mustang. At least not the gen4. Gen3 with PCMtec I believe can pin in a sensor and do a real deal flex tune.

 

[Junkyard Dog]

I meant with mustangs. You said you were guessing that a real e content sensor wasn’t being used and this was correct because as I said , nobody uses them. Not on mustangs. They can’t be pinned in like on GM cars. Yes I’ve tuned several Camaros with the real e sensor added and the PCM will get real time data on the ethanol content. That’s not possible with the mustang. At least not the gen4. Gen3 with PCMtec I believe can pin in a sensor and do a real deal flex tune.

Oh, yeah, I get that nobody is doing them with Mustangs. That was kind of the point of my post. I thought you meant, well, nobody.

I posted a video above with a kid who added the alky sensor to his Mustang, but that car was produced more than a quarter of a century ago.

EDIT: I did not realize it was physically impossible to add to the new ones. That is too bad.

 

[Gojiras breath]

The appeal of flex fuel tune is its a viable middle option if travelling and cant find e85. I think the dash display shows a/f ratios. Excuse if i'm wrong on termimology or numbers. If 93 octane shows 13:1 on display and you add a little e85 it slowly drops to 12:1. If all e85 it would display 10:1. This is a visual comfirmation not only that its working but also says you hit the right number to install the true e85 tune. Am I missing something here?

Do the devices hold 3 tunes where a person can install at a gas station, or is a laptop and internet required?

 

[Junkyard Dog]

I think the dash display shows a/f ratios.

Mine does

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