2019 tundra 38 gallon tank.

Gas vapors are not explosive, they still need oxidizing agent, which you can't find in a normally operating gas tank. Otherwise you'd bee seeing a spectacular action movie-grade blow ups on the roads very often

Fuel pump needs some gasoline. It has a container where it is fully submerged in fuel even when the fuel level is generally low in tank. The problem with cooling starts to materialize when the pump can't have enough fuel to suck into the container, which commonly happens when vehicle accelerates/brakes/turns or moves on the slope.

 

Vapors aren't explosive? TWA flight 800 I think it was. Get the right mixture of air and fuel vapor. I understand that's highly unlikely.
I'm in agreement that the fuel passing through the pump cools it but I really don't think you need 6 gallons of fuel to cool that pump. Running out of gas completely would cause heat buildup but only for a very short time and the engine would die and the pump would shut off.

 

Tank is vented to the atmosphere via carbon container during fill ups, and to the engine's intake during normal operation. It has also a diagnostic pump, which runs from time to time and makes sure there's no holes anywhere around. I.e. when everything works as designed, there's mostly fuel and saturated fuel vapors in the tank.

Sure. Now do it every fill up and post complains everywhere that it died prematurely Otherwise a good pump normally outlives the rest of the car. On the picture above is a 20 y.o. pump that I replaced only because the one way valve corroded and it was dropping fuel line pressure overnight. Duty cycle was still in the good range.

 

I never go below half, my fuel pump loves me!

 

But 2019 is under fuel pump recall!

 

I'm genuinely curious, does it actually endure more or less wear with this method? I mean it is enduring wear during each trip to and away from the pump and those minutes of run time have to be taken into account somehow. Pretty silly I know! But technically speaking and depending on several factors, it could be counterproductive and your truck's pump may not always have serious affection for your behavior.jk! FWIW, I try to avoid completely filling mine up with hopes to avoid the fairly common check valve or rollover safety valve problem that seems like a major, but easily avoidable PITA to deal with.

 

So if we are speculating a little bit, from speaking with other more knowledgeable folks on the matter, I’ve surmised two real failure modes from pumps when they are run low. Though, they are kinda the same failure, but one is over time and one is more sudden. They both involve excess heat.

The first failure is excessive wear over time from spending too much time in the hot zone. This happens when the tank is always or often run low and there isn’t enough fuel to adequately cool the pump. The pump doesn’t fail immediately, but since materials have a tendency to expand with heat, the tolerances change, parts move a little, and they wear in ways they shouldn’t because they self clearance as they heat up. Cycle this enough and eventually the tolerances on the pump grow enough to not provide enough pressure or to simply jamb when hot.

As anecdotal evidence, I’ve had fuel pumps that worked fine in the morning when cold but would cause hard starts when warm. Fuel lines had pressure, but inadequate pressure to run the vehicle. Let it sit a few hours until it cooled off outside and it would start up and drive for 10 or 15 minutes before dying.

The second failure mode is sudden, catastrophic failure - also due to excess heat. But this time, instead of inadequate cooling from low fluid level, it is simply unable to cool the pump. The pump parts expand too much, too rapidly, jamb or create excess tolerance, and die an ignominious death either on the spot or the next time you try to start it.

Also more anecdotal evidence - I’ve had a fuel pump die suddenly on a hot summers day when I ran too far past E; it got me to where I was headed, but wouldn’t restart after sitting for an hour so it didn’t get me home. Pump was 100% inoperable. Took a ride on the back of a tow truck.

I’d be curious to know if my theory is correct. Or complete bladerdash.

 

I mostly agree, but I also believe there are human and manufacturing factors to be considered along with fuel chemistry and temps. Personally I like to avoid towing and or inconvenient repairs, so I generally keep some fuel in the tank and replace fuel pumps at about 125k. Don't remember ever being stranded from a failed fuel pump either. Where or how one chooses to aquire fuel is a whole entire other rabbit hole too!

 

Oh, absolutely!

 

I would disagree that those failures are common, and would love to see any evidence that they are caused by overfilling the tank, much less just filling the tank. And you really preemptively replace the fuel pump at 125k?

 

Okay, I will rephrase-too common for my liking. Yes, about 125k they hit my to do list and within the next 5-10k they are replaced because I don't wanna dick around when the weather might not be favorable, it might be dark, I might be traveling a substantial distance, etc. Cheap insurance IMO, also nice to know that I have a working unit on the shelf after it has been replaced.

 

You are the first and only person I have ever heard of doing that. I have never replaced a fuel pump in any of the vehicles I have owned over the last 45+ years of driving. Starters-yep. Alternators-yep. But never a fuel pump.

Now that might also be an anomaly, but it certainly is not evidence that would make me adopt your approach. Curious if there other items that you do this with. Like the starter, alternator, AIS...? Seems like a complete waste of time, effort and money. In the end, it is your truck so do what you think is best.

Cheers!

 

Yep, simple wear items are replaced before they are toast. I like being able to get in my truck and have the peace of mind of knowing that I can likely go 10k miles plus at any given time with minimal concerns. I also like having the good used parts in stock on a shelf. You will never catch me driving a vehicle that I own with 150k on a starter, water pump, etc. Spent some time in my youth suffering some fairly harsh consequences from procrastinating over maintenance items. Lived and learned after having almost not lived thrice from being lazy, dumb, and cheap!

 

I know a lot folks with a similar philosophy as @2mchfun regarding fuel pumps - especially GMT400 folks. Those liked to crap out every 60-100k if you bough OEM, 40k if you bough aftermarket. I'm not saying it was guaranteed by any means, but I've swapped several of them in that platform alone, and they always die at the most inopportune time.

 

LOL Fuel pumps, starters and such are not what I would categorize as simple wear items. Those would be tires, wiper blades, brakes etc... But again, it's your vehicle. I would however love to hear the stories of how you almost died because your fuel pump or starter was not swapped out before it failed.

 

Ok, I've got one. GMT400 suburban. My wife and I had been married a year and were going on vacation with my family (parents, siblings, nieces and nephews) and decided to carpool with my folks. After thrashing for two days to get some last minute repairs done to my folks suburban, we left for a 800 mile trip (one way) with a small single axle trailer in tow with our bicycles and adventure gear loaded on it. I was napping in the backseat and while we were driving up a mountain pass, the vehicle took more throttle to maintain speed and started slowing. Thinking it was the fact that we were loaded down, it was 100 degrees out with a headwind, A/C running full blast, and trailer in tow, it didn't seem like a big deal. But then the engine cut out. So my dad put the transmission in natural and keyed the starter. The engine fired up but continued to lose a little bit of speed until it conked out again. Again, uphill with a trailer, we quickly lost speed and were unable to coast the vehicle to the shoulder.

So we were sitting partly on the shoulder, partly in the right lane of a freeway with only two lanes, with traffic - including semi trailers - quickly advancing. Unfortunately, my dad has very little experience backing up trailers and struggles especially with small wheelbase trailers. We ended up doing an impromptu fire drill driver swap in the middle of the freeway, but since we were straddling the shoulder and road, the tail of the trailer was pointed to the second lane. So I ended up swinging the truck and trailer back in the right lane to eventually get the trailer pointed the right direction and get off the road, all while fighting oncoming traffic and letting gravity do the work without power steering or brakes. To further complicate matters, there is a large 1/4 mile dip in the road right before the stretch where we were stranded, so drivers had less than a mile at 75 or 80 mph to suss out the situation and sort out lane changes and such. One semi was forced to pass us on the shoulder.

Before we left on the trip, our local mechanic suggested we replace the fuel pump simply due to miles on the vehicle. It ended up being the fuel pump that quit.

 

I thought @Sunnier taught us that it was the fuel moving through the pump that carried away thermal energy?

 

Short answer, twice due to extended cold exposure from preventable mechanical failure, and once from a preventable crash caused by hydroplaning on slick tires. All three totally preventable.

Cellular phones were not a thing at those times.

 

that's interesting. Is this relatively new? Not that I go seeking out "what recalls are available on my ____?" with any regularity.

Also, did they switch pump brands, design in 2019?

 

Your story reminds me of a 4th that I had forgotten about. I-20 Westbound in East Texas, 2.3 liter Ford timing belt let go about 11 P.M. with under $100 to my name. Coasted to the shoulder and slept for the night with countless semis rocking my cradle non- stop. In the morning walked east about 4 miles to the nearest town, Marshall maybe, don't remember. Anyway, found a Bumper to Bumper auto parts store there and they had the few things I needed for like $55 iirc. Walked back and did the belt replacement on the spot with constant fear of a big rig ending me rather quickly. Before noon I was well on my way, but them damn big rigs are no joke when they are 3 feet away from your toes at highway velocity. Probably totally preventable with a little more critical thinking applied.

 

2018 and 2019 was a mass recall for fuel pump in many-many Toyota models. Mine started acting up sometimes last summer, very rarely. Few weeks ago it decided to prevent engine starting 9 in 10 times, so I had it replaced under recall.

 

Thanks. I'll ask service team about it next time I'm in. They'll burn through a cell phone battery calling me about the headlight wiring recall (which I decline, as I have LEDs), but have never mentioned this. Is it VIN specific like the 3rd Gennanigans or all units in those MY's?

 

I too have LEDs, but the wiring recall is for blinkers. I found the TSB and did it myself, though.

Run your VIN here: https://www.toyota.com/recall/ Or call dealer.

 

My understanding was that the recall was something like a different gauge wire (cost cutting/re-design) potentially overheating if hi/low beams were on for a long time together as that's how the assemblies were set up beginning 2018 with the factory LED headlamps, as that's how they are wired to run (hi/lo simultaneously when hi beams are engaged).

Thanks for the link though, will check it out.

 

No, the blinker wiring recall is a different one. The connector was mispinned, basically.

What have you done to your 2.5 gen Tundra today? <- has link to DIY pdf

 

https://www.tundras.com/threads/38-gal-tank-experiences.22954/page-29#post-3780302

There's already 30 pages of discussion about this......

 

and 8 more to go!

 

Sounds like that was very scary. However, you didn't almost die.

 

Again, may have been very scary, but you did not almost die because of the mechanical failures. You were not prepared to deal with cold weather. And hydroplaning on bald tires did not happen because you preemptively changed them before they were dangerous or failed.

 

I have had a similar experience, and to be clear, belts, hoses and tires are what I would call "simple wear items" that I have and do replace before they fail. But again, I would not categorize your experience as near death.