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RaderNed

Fuel tank volume

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I bought a 1985 21' Sunrader a while back and was told by the seller that it had a 17 gallon tank. Indeed, judging by the fuel guage it seemed to be 17 gallons, as when the guage read near empty, around 17 gallons would fill it. Poking around under the vehicle for other reasons, I noticed that the fuel tank seemed pretty large. It's rectangular and measures 34" x 13.5" x 13.5". Using an online volume calculator, and taking the slightly rounded corners into account, it would seem this is a 26 gallon tank. Is there something I'm not considering here that might make it 17 gallons? If it is a 26 gallon tank, I'm thinking that perhaps someone stuck the stock bracket and sender on it, hence the guage readings. If that's the case, am I right in thinking that the pump is likely sitting a few inches above the bottom of the tank? I don't mind the sender/guage being off, but if the pump is sitting above the tank bottom is there a way to put an extension hose our tube on the bottom of it to make it reach the bottom of the tank ( with the sock  filter attached to the end)?

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For many years Sunrader had an 26 gal tank as an option. You would have to extend the float arm to make it read correctly in a 26 gal tank. I would have thought that Sunrader would have the stuff to make it read right down pat.

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Those of us with the 17 gallon tank usually hit empty at 13 gallons. I bet your tank is set up fine. Just the way the gages seem to work on these. I do remember someone saying once that the 26 gallon tank didn't really hold that much. Could you post a picture of it. I don't remember it having rounded corners.

Linda S

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15 hours ago, RaderNed said:

I bought a 1985 21' Sunrader a while back and was told by the seller that it had a 17 gallon tank. Indeed, judging by the fuel guage it seemed to be 17 gallons, as when the guage read near empty, around 17 gallons would fill it. Poking around under the vehicle for other reasons, I noticed that the fuel tank seemed pretty large. It's rectangular and measures 34" x 13.5" x 13.5". 

An OEM 17 gallon tank is approx. 37" X 16" X 13".  A 19" tank is 37" X 16" X 14".  I suspect you just have a standard 17 gallon tank.  As far as when your gauge reads empty - all depends on where the float is set at.  The float-arm can be set so the tank reads empty with only 1/2 gallon left, or more-the-usual - when there are 3-4 gallons left.  If it reads "empty" when it IS near empty - it likely stays on "full" for a very long time after a fill.  If set the more common way - "full" disappears pretty quick, but there is lots of gas left then the gauge reads "empty."

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I can't believe Toyota didn't put low fuel warning lamps on the RV's.

total fuckin crapshoot, sucks.

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My first Toyota MH did have a fuel warning light.  That was an 87 Dolphin with 4cyl 22RE engine. 

Then I went to a 90 Dolphin with V6 and then to a 94 Warrior with V6 and neither has the warning light. I really miss it.

but yes there are some Toys out there with the light.

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Thanks all for the feedback. Here is a photo of the tank from the back. Is this what the standard 17 and 19 gallon  tanks look like? 

image.jpeg

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9 hours ago, linda s said:

Nope it sure don't. You are the proud owner of a 26 gallon tank from transfer flow.

Linda S

tank+041.jpg

Thanks for the confirmation, Linda. Now, can the sender just be adjusted to read correctly? I imagine I'm going to have to drop the tank and pull the bracket and pump anyway, just to figure out what the issue is. I have a feeling someone may have put the bracket and sender from a 17 gal tank into this one. If that's the case, can it somehow be modified, perhaps by extending the tube/sock  below the pump?

Another question: I have access to the portion of the top of the tank where the bracket/sender is mounted (thanks to a metal -plate-covered hole in the floor someone prior to us made). If the ventilation is good (like a windy day with all windows and doors open), still too  dangerous to pull the bracket without dropping the tank? And full tank vs empty? 

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I wouldn't touch a thing. It's not leaking and you already know it shows empty at 17 gallons. We all have a large reserve on our tanks and we just get used to the gage being off by that much. I have heard that the 26 gallon tank really only has 22 or 23 gallons of usable gas meaning the original install didn't adjust the pump bracket enough to lower it into the tank enough. I also heard that the reserve on the large tank is 5.5 gallons. Greg Harbustan the owner of this site used to have a Sunrader 4x4 with the 26 gallon tank and he had gauge problems too so they may have all been off.

Linda S

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If it bugs you, then use the trap door and remove the pickup and measure the depth of the tank and compare to the depth of the pickup. After extending the pickup, then check the swing on the float and see if matches the depth of the tank. Do a cut/extend job float arm and wrap the joint with small copper wire and solider.

OR do what Linda says and just write down the mileage when you fil up and fill up again XXX miles later. Just sneak up on the XXX mileage number a little bit at a time, don't, just start an 250mi.

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16 hours ago, linda s said:

Nope it sure don't. You are the proud owner of a 26 gallon tank from transfer flow.

Linda S

tank+041.jpg

So is there actually a 26 gallon tank that will fit in the space allotted for a 17 gallon tank? Is this also true for my 85 Dolphin? Both I and my mechanic recently searched high and low for such a beast. No luck. My stock tank may have some problems looming on the horizon due to a shoddy conversion/addition of a supplemental tank which has since been removed. We're doing just fine with the 17 gallon tank. Not really a problem to fill up more often. But if I ever need to replace that original tank I would love to put in a 26 gallon model, strictly for convenience.

Can you point me to a source for this tank?

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37 minutes ago, jmowrey said:

So is there actually a 26 gallon tank that will fit in the space allotted for a 17 gallon tank? Is this also true for my 85 Dolphin? Both I and my mechanic recently searched high and low for such a beast. No luck. My stock tank may have some problems looming on the horizon due to a shoddy conversion/addition of a supplemental tank which has since been removed. We're doing just fine with the 17 gallon tank. Not really a problem to fill up more often. But if I ever need to replace that original tank I would love to put in a 26 gallon model, strictly for convenience.

Can you point me to a source for this tank?

Haven't been made in many years. The last company that made the big tanks for tanks for a Toyota was Northwest metals and they sold their tank manufacturing to Sunset metals and they don't do Toyota tanks.

Linda S

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On September 6, 2016 at 0:24 PM, linda s said:

I wouldn't touch a thing. It's not leaking and you already know it shows empty at 17 gallons. We all have a large reserve on our tanks and we just get used to the gage being off by that much. I have heard that the 26 gallon tank really only has 22 or 23 gallons of usable gas meaning the original install didn't adjust the pump bracket enough to lower it into the tank enough. I also heard that the reserve on the large tank is 5.5 gallons. Greg Harbustan the owner of this site used to have a Sunrader 4x4 with the 26 gallon tank and he had gauge problems too so they may have all been off.

Linda S

Okay, thanks again. I think I'll just keep some extra fuel onboard and see how far the tank will go. 

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I wouldn't run it dry. You have an in tank pump and after all these years there a bunch of gunk down there you don't want drawn into your pump. Just live like you've got a 22 gallon tank. Get you worlds father than the rest of us and you'll never run out of gas. I know another person with a 26 gallon tank and he's run out twice. Must be like those Prius people. Goes so far they forget it still needs gas

Linda S

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I'm a "Prius" person and @ 51mpg hardly ever look @ the gas gauge. Not like driving the Toy where I'm Always looking @ the gas gauge lol!!

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On September 9, 2016 at 8:14 AM, linda s said:

I wouldn't run it dry. You have an in tank pump and after all these years there a bunch of gunk down there you don't want drawn into your pump. Just live like you've got a 22 gallon tank. Get you worlds father than the rest of us and you'll never run out of gas. I know another person with a 26 gallon tank and he's run out twice. Must be like those Prius people. Goes so far they forget it still needs gas

Linda S

Would it help to drain the tank (there are several drain plugs on it)?  That might get some of the "gunk" out, and would also indicate how much fuel remains in the tank when the gauge reads dead empty.  The only thing it wouldn't help with is knowing how much of that additional fuel is accessible to the pump and hence usable.

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Well if it was me and I tried to drain the tank the plugs would be so rusted in that I would damage the tank trying to get them out and then I would really be in trouble. So I wouldn't do it. If you must tinker with it it's up to you.

Linda S

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My Dodge truck holds 85 gallons of diesel and gets 19-20 MPG. It certainly still gets empty now and then and I feel like I need to take out a bank load to fill it.   Seems a high-roof Toyota, getting 14 MPG, with a 20 gallon tank is certainly nice to have but still gets empty pretty quick. My 1978 Toyota Chinook has around 30 gallons capacity and gets 19-20 MPG.  Needle on the gauge still moves quick enough.

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Wow...17 gallon tanks...my 1990 Odyssey has a 15 gallon tank!

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All 2wd Toyota trucks in 1990 came with a 17.2 gallon tank. Maybe you have 2 gallons of gunk at the bottom

Linda S

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1 hour ago, bufbooth said:

Wow...17 gallon tanks...my 1990 Odyssey has a 15 gallon tank!

Some of the Toyota trucks of that generation had very conservative tank gages. You may very well have an extra 2 gallons in the tank even though your gage reads empty.

Only way to know for sure is to drain the tank and refill, or drive until you actually run out of gas (not the best way). Your tank is probably 17 gallons. Your fuel gage is probably the culprit.

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I actually ran out of gas traveling late one night (on the way to Yellowstone), could not find an open gas station.  My 1990 Odyssey went into chug mode before it died.  The next morning after walking to a gas station, they gave me a 1-gallon gas can.  After adding gas and driving a mile, I could not get more than 14.5 gallons into the tank.

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If you just need to get all the fuel out of the tank, you will have to do a bit of tweaking. Drop the tank, pull the pump and make sure the tank is clean inside. Put a small ball of clay and make sure the fuel pump sock goes to the bottom of the tank.  Make sure the vent in the top of the tank is clear.

P.S. running the tank dry is HARD on the fuel pump.

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