Flex Fuel or No Flex Fuel. That is the question.

The primary and ONLY difference between the FF and Non FF street legal vehicles is in the software level.
The narratives of hardware such as fuel line, and all other engine components being eaten up by the alcohol is bullshit. They already made the internal components to be alcohol compatible like 20+ years ago when they decided to add that 10% ethanol in the pump gas. And I can tell you that first hand based on how my 2005 2.4L Camry (non FF) has been running with E85 pump gas for the past 6 years. If there shall be any leaks or fuel pump failure, you would think it would show by now eh? I also converted two other non FF vehicles to take E85 with conversion kits to these days. No issues. I run my 2018 Tundra from day one with E85 as well.

Now the software. Due to the fact that 1 unit of ethanol has about 30% less BTU than 1 unit of gasoline, as long as the ECU is advance enough to make up that 30% short (basically give the engine 30% more fuel), the engine will not be in the risk of running too lean.

Oh! And all the "phase separation" of alcohol and water and all that. Well, I didn't see it when I took a scoop of sample out of the fuel tank on my Camry last time I changed out the fuel pump gauge (not E85 related FYI. It was already broken before I started pumping E85). The car runs great to these days with 221k miles.

Why experimenting on the Camry, u wonder? Well, I wanted to kill it so my wife would okay my WRX purchase. lol But this thing just simply does not die~.

 

Yep, you can use that Camry as a coffin.

 

The FF tundra has larger injectors and a different fuel pump.

'Tis nearly time to switch back to e85. I don't run it in the winter, mainly due to range issues with the 26 gal tank.

 

There is an issue with the computer/programming with regards to the Flex Fuel trucks.

Even if you don't run E85, the calculated ethanol % will creep up over time. Eventually it causes a no-start condition and replacement of fuel pump is required.

Toyota has a TSB on this, but it appears to be up in the air if works or just resets the time table on next event.

Some have mentioned that the FF calc can be turned off by the dealer or Techstream, and ethanol % reset to a reasonable number (10 or below).

Not sure if all FF trucks are affected, but it seems to be a decent number.

 

Real men put 100LL in their trucks..








Pilot humor. Dont do that.

 

I had a discussion with a Toyota Master Mechanic about this.

He believes the problem is the fuel pump is failing, and the ethanol % - which is just from a sensor on the cat - is just a symptom of the problem.

 

I have a FFV. If I had to do all over again, I'd not have an FFV

 

Nooooooooooooooo!!

 

Don't get me wrong. My truck runs like a scalded dog, but the idle is erratic at times and I know for a fact the ethanol numbers are outta whack. I'm tuned and that doesn't even matter.

 

I didn't want an FFV either.

Was my only choice at the time.

So far it works just like a normal engine. And there's no way I'd ever run E85.

 

I've never put a drop of E85 in this truck

 

Same here. We don't have E85 in the DFW area but I see it in central Texas. I don't see any benefit to running it and certainly don't want to support the ethanol industry more then I already do. They need to find another source for this crap corn prices almost doubled last year. I see people up north have an option to run higher octane ethanol free then we have around here. Ethanol free in DFW is always 87.

 

I purposely purchased a non FFV as I like my truck to actually start in the morning. Oh, and supercharging FFV is a way bigger PITA.

 

Hard to get away from it down here. Hell I didn't see e-free gas until I hit a Buccees up on a road trip headed south.

 

Probably why I'll never make the jump to SC

 

Yea I don't use it either but would like to try Ethenol free. Only sell it at Buccees thats 30 mins away from me.

 

I'd be curious to see if it makes my FF 5.7 run differently.

 

I dont know if it would make it smoother but after trying Royal Purple last month seemed to help mine. But I don't want to turn this into an oil thread.

 

Just thinkin' havin 0% ethanol in the fuel could alter the fuel numbers in the ECU to make it idle smoother.

 

Mine idles fine with E10.

 

When running E10 my alcohol number in the ecu is usually showing 2% if the scangauge is honest. Not much room to go down with ethanol free.

Best way to a smooth idle is grab a good size trailer and pull it around for a while to burn all the carbon out. Or run a couple tanks of e85, that will blast it out too

 

This is real. I had a 2013 FFV I purchased new and in the last 2 years during cold weather / winter months (rare, but I'm in Houston area) the truck would struggle to start and would ALWAYS take 2+ cranks to start (but it ALWAYS started) and generated a plume of smoke. I did my research and narrowed it down to the T-SB-0166-19 TSB which basically states to fix the problem you have to reflash and most likely replace the fuel pump ($$$). I was all set to try that and had an appointment scheduled to have the flashing done first to see if it alone would fix it (after talking with the dealership service person) but decided to just trade it in on a 2021 1794 2 weeks ago and be done with it. My brother has the same FFV but in a 2016 model and it has the same thing, it was originally bought in Arkansas. Disappointed in Toyota, they should fix this and WILL pay for the flashing but not a new fuel pump which is what really fixes it. The service person said in later years they changed the fuel pump design for FFV engines or maybe just quit selling FFV entirely. FFV sucks man but that was the only issue I had with the truck.

 

It makes sense, if the fuel pressure is low then the pcm would need to command more fuel to meet afr, and if fuel trims go way up during the alcohol learn then it must assume more ethanol. I wonder if the fault is the pump or just its regulator. The trucks that go full alcohol mode on gas aren't leaning out and stalling out so the volume is still getting there.

Winter is about done and I just switched back to the corn oil. Hello torque oh how I have missed you so.

 

Flex fuel engine here. I don't use E85 and never had a problem with my truck starting, idling, or running like a bat out of a warm place when needed.

 

I never used E85 (or did my brother), I hope your luck continues. The fuel pump IS NOT going bad, it's a bad design and was replaced. The flashing fixes it for awhile but everything I read says it always came back until the fuel pump was replaced. I would have lived with it but wanted my dream truck, the Brown 1794 in the last year of the V8 (not a fan of turbos) and wanted a 38 gallon fuel tank/better sound system/1794.

 

I bought a FF 2018 with 38k miles 1 year ago and just got it back after 3 months at the dealership replacing the fuel pump and whatever else is associated with that TSB emissions warranty. Truck has 57k on it, I hope this is not going to be something else I’ll be worrying about down the line. I should of done more research in the Tundra before I purchased as I would of avoided the FF.

 

Was this replaced under warranty or did you have to pay for it? I was wondering how much the dealership would charge to replace the fuel pump, it has to be expensive...

 

yes it was covered under warranty, but it was a warranty that Toyota offers for the flex fuel vehicles that have under 80k. I was unaware of this warranty but was thrilled when I learned that it was covered. Tundra was experiencing shutting and hesitation on cold starts before the pump was replaced.

i owned a 09 4Runner and the fuel pump went out on it, that replacement cost around $1400( dealer covered as we had owned the truck for two weeks).

 

Thanks for the info. My 2013 had just rolled over 80K when I traded it in. The service writer at my local Toyota dealership told me the flashing would be covered but not the replacement of the fuel pump if it needed it. I was on the fence as to make some upgrades to it (46 gallon aftermarket fuel tank/new radio with backup camera moved from mirror to new unit) but this made it easy for me to just punt. I feel sorry for the person who buys it but it was in good shape with no issues other than the FFV issue.

 

3 months to replace a fuel pump and TSB emission work? Holy cow! Why did they have to keep it so long? Has to be more to it than that.