Gas tank or fill neck modification?

[Rwhockey29]

1999 3.4 Limited here. my light comes on right around 245 miles, and when i fill up its usually 13.5-14 gallons. ive pushed it a bit farther, but honestly i like knowing that "E" means i have another 20+ miles i could drive if i need too.

also not sure if its true on our trucks, but ive heard running your tank completely dry can shorten the life of the fuel pump. i know on my audi the fuel pump was somewhat cooled by the fuel in the tank.

 

[7echo]

On my '99 I pump til it shuts off and get 13.5 to 14.5. Then I pump another gallon and stop. It takes a few slow flow start/stops of the pump to get the extra gallon. Then I get, on avg, about 15.4 mpg in city driving.

[MENTION=10169]TheDurk[/MENTION], let us know if it looks like a new tank could be made to fit the original spot but built with more capacity. Since there isn't a way to add a fuel cell that is easy I am wondering if we could just make a custom tank that utilized all the space more efficiently and get maybe 5 extra gallons.

 

[octanejunkie]

Here you go:

http://www.toyotaparts.metro-toyota.com/FUEL_GAUGE_INACCURACY_T-EL010-00.pdf

Here is the sender and the vent pipe I am talking about (the tube that ends by the ring on this guy's finger. That's what I plan to shorten. I just need to find a good pic of the newer sender for '99s.

FWIW, my vehicle calls for procedure 2, according to the linked PDF, but its a tad out of warranty.

Thanks for the pic. That actually looks like the fill tube. Isn't the fill just a smaller tube inside of the vent tube; like a tube within a tube? That's how it is on the Ford Ranger - I know because I used on on my Chevy when I moved the tank to the rear and made it fender fill (vs bed fill)

EDIT: pipe in pic by ring finger is indeed the vent tube, thanks!

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[SnoViking]

Not true for a '99, like myself or the OP. For some reason they modified the in tank vent-pipe in '99 and made it longer. They then revised the part as part of the fix for the funky fuel gauge that a lot of '99s had. You really can't get a full tank into a stock '99 because of this. 12.5 to 13 gallons is about the max. I have my tank out while I'm doing a frame swap, and I'm going to cut mine back. I'm just looking for the thread that shows the two different styles of vent pipe side by side so I get it right. (Anybody have that?) Anyway, I'll let you all know how it goes when I'm done. Gonna be a couple weeks yet.

In my case, I was NOT one of the s/n's with the funky fuel gauge (mine works perfectly) but I did get the long vent-pipe and I was not eligible for the fix while in warranty. (There is a TSB somewhere that spells this out.)

(I too have a '99 and usually fill up once the fuel light comes on. Max fill is approx. 12 gallons. My average fill up is 10.7 gallons over the past 6 years)

Just for clarification: The extended tube (shown by the guy's ring finger in the picture) is for venting? Which in turn, with the new vapor sensing nozzles, only allows about 12-14 gallons to be put into the fuel tank (which has a 18.5 gallon capacity?)?

So by shortening the tube, you gain the ability to put more fuel into the tank?

 

[TheDurk]

(I too have a '99 and usually fill up once the fuel light comes on. Max fill is approx. 12 gallons. My average fill up is 10.7 gallons over the past 6 years)

Just for clarification: The extended tube (shown by the guy's ring finger in the picture) is for venting? Which in turn, with the new vapor sensing nozzles, only allows about 12-14 gallons to be put into the fuel tank (which has a 18.5 gallon capacity?)?

So by shortening the tube, you gain the ability to put more fuel into the tank?

All I know for sure is that they revised the tube to make it shorter. That is the tube that allows air to escape as gasoline fills the tank. When liquid in the tank rises to block the tube, air can't escape so gasoline backs up in the fill tube and triggers the nozzle shut-off.

BUT, I do not know of anyone who has actually modified the tube. There was a poster with a '99, a few years back, who subbed out his sender unit per the FSB attempting to resolve his flaky fuel gauge. He photographed the two side-by-side. That tube was clearly shorter, and afterwards he got more fuel into his tank. He also had a more accurate fuel gauge, so the causality is not perfect. But it certainly makes sense to me. That's when I got the idea. It's just that now I have the opportunity to do it with the sender on my kitchen table.

I thought I had bookmarked that thread, but unfortunately, I can't find it. It might be on YT, and I haven't looked there yet. Anyway, I'm going to try this whether I find it or not. If the tank overfills, I can always go back and put a piece of fuel hose on it to restore.

EDIT: I found a link to the thread I'm looking for. It's to a dead personal page. That explains why it's gone from my link collection--I expunged all the dead links last year. I did find a pic of the revised '99 fuel tube assembly (77203-35461):

You can see the vent-tube is far shorter than the one pictured up thread. I'll post a pic of mine later.

 

[frodiesel]

1999 3.4 Limited here. my light comes on right around 245 miles, and when i fill up its usually 13.5-14 gallons. ive pushed it a bit farther, but honestly i like knowing that "E" means i have another 20+ miles i could drive if i need too.

also not sure if its true on our trucks, but ive heard running your tank completely dry can shorten the life of the fuel pump. i know on my audi the fuel pump was somewhat cooled by the fuel in the tank.

We have a winner here. I would not recommend overheating the fuel pump by running the tank dry. On the honda odyssey we have the light comes on with more than 6 gallons in the tank.
A better picture is a flir gun pointing at your heat soaked empty tank, how hot is that pump?

Sent from my SM-G900P using Tapatalk

 

[octanejunkie]

We have a winner here. I would not recommend overheating the fuel pump by running the tank dry. On the honda odyssey we have the light comes on with more than 6 gallons in the tank.
A better picture is a flir gun pointing at your heat soaked empty tank, how hot is that pump?

Sent from my SM-G900P using Tapatalk

Agreed. These pumps are meant to be cooled by the fuel itself and running the tank dry is not a good idea with any in-tank pump.

The issue is not about getting more out, it's about being able to put the most IN and expand the drivable range of the vehicle.

The vent tube allows the tank to breathe while filling, and also sets the "max full" level - so fuel has room to expand inside the tank when it heats up.

The vent tube being "too long" prevents filling the tank to the safe maximum, decreasing the total fuel the vehicle can carry, and shortening the drivable range.

If there is an "easy" and safe mod to allow more fuel to go in, then that's what I'm looking for. I can live with my gauge showing empty and me knowing I can push another 80 miles in a pinch, but I hate never being able to get the needle to the full mark on the gauge when filling up. Which is also due to the overly-sensitive vapor sensing fuel nozzles found at CA gas stations.

FWIW, my average fill up when the needle is in the middle of the fat E line is about 14-15 gallons. However, if I fill up as soon as the idiot light comes on, I only fill about 12 gallons.

 

[Skinfaxi]

If shortening the vent tube allows another two gallons or so, that's 40 extra miles before the light comes on. I'd say that's worth it.

 

[TheDurk]

1999 3.4 Limited here. my light comes on right around 245 miles, and when i fill up its usually 13.5-14 gallons. ive pushed it a bit farther, but honestly i like knowing that "E" means i have another 20+ miles i could drive if i need too.

also not sure if its true on our trucks, but ive heard running your tank completely dry can shorten the life of the fuel pump. i know on my audi the fuel pump was somewhat cooled by the fuel in the tank.

Yeah, it is true for our trucks, but that really isn't a concern for my test. The pump ran only for about five minutes to empty the last five gallons and I broke it up so it didn't overheat. In actual use, burning five gallons to go dry while driving will take an hour or more as the pump runs full bore all the time with all the excess just returning to the tank.

I usually never go below 1/4th unless no choice exists--but it happens. So getting more in is even more attractive to me.

 

[octanejunkie]

So this just happened

Filled 18.828 gallons after driving 303miles since my last fill up.

I suspect the gas pump may be in need of calibration.

This is also a rare sight for me

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[SnoViking]

If shortening the vent tube allows another two gallons or so, that's 40 extra miles before the light comes on. I'd say that's worth it.

My thoughts exactly. Why should I carry a 3 gallon rotopax, or 5 gallon Jerry can when I can just put 3 more gallons in my tank?.....

 

[TheDurk]

OK, I did it. My tube was at almost four inches long. I cut 1½" off leaving it 2½". Here is the pic:

The silver mark shows where I cut the vent pipe. I thought I had an after pic but I guess not. Sorry. The Dremel cut-off wheel did a nice quick job although there is not much room. It's now been bolted back into the tank so I can rustproof it.

It will be a few weeks before I finish the project but I've bookmarked this thread and I will eventually post the results.

 

[octanejunkie]

OK, I did it. My tube was at almost four inches long. I cut 1½" off leaving it 2½". Here is the pic:

The silver mark shows where I cut the vent pipe. I thought I had an after pic but I guess not. Sorry. The Dremel cut-off wheel did a nice quick job although there is not much room. It's now been bolted back into the tank so I can rustproof it.

It will be a few weeks before I finish the project but I've bookmarked this thread and I will eventually post the results.

Anxious to see how much you fill up on the normal refuel

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[DED&DED]

Is it necessary to remove the gas tank in order to remove the sender unit. I have a Gen-3 with a non working fuel gauge. It is very strange--when the trailer lights and plugged in the gauge works but it only reads half-scale. Any suggestions--I did the TSB with no success. Is a new/replacement gauge needed?

Ken--99, SR5, 5 speed, no e-locker, 289,000 miles

 

[Juppers]

Is it necessary to remove the gas tank in order to remove the sender unit. I have a Gen-3 with a non working fuel gauge. It is very strange--when the trailer lights and plugged in the gauge works but it only reads half-scale. Any suggestions--I did the TSB with no success. Is a new/replacement gauge needed?

Ken--99, SR5, 5 speed, no e-locker, 289,000 miles

I had a similar problem. The sending unit was fine, the gas gauge in the cluster blew a resistor. I just made a solder bridge over the blown resistor and it the gauge has worked fine since.

 

[DED&DED]

Juppers----Thank you!!!

 

[hour]

It will be a few weeks before I finish the project but I've bookmarked this thread and I will eventually post the results.

Ermagerd please do update when you can. I'm about to drop the tank on my 99 to do fuel pump replacement and would love to feel confident in trimming any amount off of the tube while I'm in there. If it doesn't help - fine, no loss - but if suddenly I overflow every time I try to fill up... that'd be wank.

I average a 13.5 gal fill up after riding the gas light for 50 miles. It wasn't until this thread that I realized I was probably running my tank on near fumes every damn time. That could explain why my fuel pump might be causing me problems, and why the previous owner claimed to have replaced the fuel pump just prior to when I bought it 3 years ago. He, like I, probably drove it for years thinking the gauge was screwy or the tank was dented and riding til far below the E line.

 

[MountainBiker]

I have a 2000, and was very disappointed with the 16-16.5 gallons i could use (tested by running out of gas a couple times.) I took to "topping off" the tank, adding as much as 2 gallons after the pump had shut off. This method sometimes gets gas coming out the filler tube, and it yielded right around 18-18.5 gallons of fill from a dead engine. But that resulted in very strong fuel vapor smell from the charcoal canister about 1-2 hours after topping off. This didn't happen all the time, but it was enough to make me stop topping off the tank. Now I just let the pump shut off by itself.

So I spent waaay too much time pulling the gas tank to install the redesigned vent tube. Below is a picture stolen from one of the forums of the old and new units, mine looked just like this. The result was a fill of 17.0 gallons when the tank is run until the engine dies. The light now typically comes on when i've used 14.0 gallons.

Removing the tank was such a PITA, that I wouldn't recommend doing this, and I totally regret doing it, it wasn't worth the effort for 0.5 gallons. If you have a body lift though, it will be easier. I replaced the level sensor at the same time(recommended by the TSB), and that was a more significant improvement as my fuel gauge now reads more consistently.

Several years ago I swapped the tank on my '02 taco from the 16.5 gallon tank (standard with the 2.4L 4-banger) to the 4wd 18.5 gallon tank, and that was a piece of cake compared to the 4rnr. Both of the taco tanks were exactly as advertised when the engine dies from low fuel, 16.5 and 18.5 gallons respectively to refill, with no topping off.

BTW, the fuel running through the pump cools it. However, if it were anything but a Toyota, I might also be afraid of running the fuel low all the time.

For reference:
Dropping the tank
Fuel tank removal

 

[SnoViking]

Any updates on the fuel pump?