Opinion: is the flex fuel engine a dealbreaker for you?

Just curious in hearing how everyone would make peace in their decision. If a truck popped up at the dealer in your price point spec’d at mostly what you wanted, one-owner with documented 5k oil changes from the dealer, but was FFV and you have no idea if e85 was run, is that a dealbreaker for you?

I’ve been reading through old posts all morning, so I’m curious to see how these trucks are fairing as they age. Seems like a lot of people were settling for FFV based on availability alone back in the day.

 

My truck is a FFV and I fell into the category of settling when I bought it. Having said that, I would 100% buy my truck again in a heart beat, I personally though the FFV was a bigger deal than it has ended up being. The only problem I've had is the fuel alcohol percentage issue, which is really minor in the grand scheme of things. I currently have 123K on my truck, and have no doubts that I can easily get three times that out of it with the proper maintenance. If the truck has all of the other options you want but is a FFV, then I'd personally pull the trigger.

 

This is pretty reassuring to hear. I don’t even have any e85 stations near me, didn’t really plan to ever run it, nor does the state have many e85 stations for its size. I would imagine previous owner wasn’t going out of their way to run e85, but there does appear to be one e85 station out by that dealer.

 

At the end of the day, the truck is designed (theoretically) to run on E85, so it should be fine even if it has been run. As far as I can understand it, once the fuel alcohol percentage is reset then the slate is wiped clean in terms of MPG's and the ECU thinking E85 is present.

 

If you're in a hurry and need to get the truck now, the FFV isn't what I would call a dealbreaker. That said, I wouldn't buy a Tundra with FFV if I was looking again. The ALC% creeps up whether you use E85 or not. You will need a bidirectional scanner so that you can monitor and reset as needed. The computer is adjusting fuel delivery based on this reading. Even without the hard starting, it may be delivering more fuel than needed based on an elevated reading. Eventually you get the hard starting due to essentially flooding the engine on startup. There's the scanner tool work around, but why bother if you have time to find a non FFV one. The TSB or whatever to fix it, rarely fixes it for people on this forum.

 

My 2015 is a Flex Fuel and I would not hesitate to buy it again. I've had zero problems with it.

 

Bought mine at 166.xxx miles. Now has 175,000 after 1 year. FFV and I have had to reset my Fuel Density with a XTOOL D7. Other than that I changed one light bulb. Would buy again.

 

I'm in the same boat. Wasn't a deal breaker, I found a great deal. If I had time to shop and an equally priced non-FFV available I would've gone for it instead but didn't have that option. I have techstream and have had to reset my Fuel Alc % twice now. Hard start being the first issue, now I just do it once I start seeing it creep up. My prior 2014 Tundra was also a FFV, I had to replace a fuel pump on that one at 190k. My guess is the FFV killed it over time but I never had any side-effects until I started getting poor gas mileage and then the following day it went into limp mode. Happened fast so never had the time to investigate. Replaced pump, drove for a few thousand miles and traded it in for my 2017 CM.

 

Common experience. Mine thankfully is not a flex fuel, got mostly lucky as I didn’t understand the issue when I was buying. My BIL didn’t get so lucky. His FFV has given him some trouble.

 

Where in techstream do you find the Fuel alc %? What number is correct and when do you reset it?


I also have a FFV but don't use e85.

 

Everyone is making really interesting points here. I appreciate everyone’s input so far. Really interesting points about the sensors creeping up and hard starts, and almost has me wondering if that’s why the individual traded the truck in to begin with.

 

Yeah I kind of wondered the same thing on my 2017. Like maybe this is why it is listed so cheap. Didn't happen during test drive, happened a few days later. Almost like they cleared the ECU prior or something. Nonetheless love the truck and the reset was fairly simple once I had techstream.

 

I was really wondering why this specific truck was at the price point it was at, and this very well could be the answer to that question. Definitely seemed 5-8k cheaper than comparable ones I’ve seen.

 

For me, yes, FF is a deal breaker.

The odds of having problems (however slim they might be) are greater with it than without it.

With plenty of non-FF trucks available, that's all I ever needed to know.

 

When I first started looking for a new-to-me Tundra, yes it was a deal-breaker; along with other things like the '18 and newer models dropped the trans cooler so I focused on 16/17 model years.

On further investigation, I read several comments on a variety of Tundra boards that if you never run E85 (I don't plan to) that it's no difference you just have the option to run E85 if you ever wanted to. I was able to speak with the previous owner and he never ran E85. The common issues is that it makes less power w/ E85 and the oil change intervals are shorter. I shopped around for a long, long time and this particular truck had everything I wanted, was very well taken care of, and I got a great price.

That being my previous understanding, is the hard starting symptom something that only occurs when you DO sometimes run E85 or is it something to look forward to with my new 2016 truck?

 

from what I’m understanding with the FFV is the computer detects alcohol concentration in the fuel to adjust fueling ratios. Even if you only run regular it gradually creeps the number up on its own which eventually results in hard starts because it’s flooding the engine with gas, in addition to poor economy. People say Toyota reflashes it (or they do themselves with a scan tool) and it goes away for awhile but gradually comes back. Some people don’t seem to ever see the issue though, so that’s why I’ve been tossing the idea around. It may never be an issue for you.

 

I’m convinced the issue is caused by dirty or malfunctioning O2 sensors - I’ve reflashed mine twice. Once you have the capability it’s no big deal and can be done in a couple minutes.

 

Mines a flex fuel with almost 70k miles. No issues to date. I didn’t even know it was a flex fuel until I had it tuned and they told me it was. Kinda want to buy that xtool thing and reset it and see if I get better than 12.8 but I doubt it and $300 is a lot of money to experiment with.

 

I have 2 tundras both flex fuel. One is just shy of 500k and the other is at 311k. No issues. Never ran E85.

 

I looked at 4 before I bought because everyone I looked at was a FF until THE one popped up

 

Bought mine with 90 something on the clock and am over 110k now, no issues and would not hesitate.

 

'18's still had trans coolers and were first year with TSS

 

No issues with my 2010 flex fuel with ~120k

 

You would probably benefit from a reset. I was getting 13.4 @ 18% indicated on non-ethanol fuel. Now at 14.5 on 10% ethanol fuel after reset.

 

Interesting. Would take two years to pay off the tool at that rate. Hmm.

 

I have a 2018 Tundra Flex Fuel and I have not had any problems. I have a question, can you reset with Carista software?

 

I originally wanted to math this out to see if the investment would pay itself back for you, but I didn’t know what the difference would be, so I’m glad to see you were able to work this out. I imagine on top of resetting the fuel alcohol %, the other benefits of having it are a bonus.

 

If you plan on forced induction in the future I would not buy FFV. I purposely looked for a non FFV knowing I would be supercharging it at some point. Just one more consideration.

 

I’d be more inclined to run higher ethanol if I was forced induction. Higher octane and better knock resistance.

 

I only drive about 8k miles a year. If I drove 15k like I used to it would pay for itself in a little over a year.