Author Topic: Shrinking Gas Tank? Engine Stalling.  (Read 1319 times)

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Offline dwtaylorpdx

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Shrinking Gas Tank? Engine Stalling.
« on: September 02, 2010, 11:43:25 PM »
Well last weekend I pulled the fuel tank on the assumption that my pump was failing.
IU've had this high temp low gas level gremlin that's been driving me crazy.
Drive up hill with a well warmed rig if the temp outside is near 100 the fire goes out in the engine.

The problem would go away when I filled the tank so I assumed the pump was getting hot and vapor locking.

When I got the tank on the ground and removed the bolts the gauge/pump mount popped up about 1/8 of an inch.

In the slush tray in the tank there are obvious marks where the pump and return pipe
had been rubbing the bottom of the tank.

With the new strainer and pump the unit wont go back in the tank without putting a lot of
pressure on the unit even after I shortened it by 1/4 inch.

Looking at the tank with it clean and out of the skidplate I can see  warpage in the plastic,
I think the tank has shrunk from being hot and aging.

Anyway I am 1 hour of irritation and about 50 bucks worth of steel from building a
new tank that won't need a skid plate and will carry a extra 5 gallons....... ???

Heck I might be able to get another 10 of I really fool around with it...

Dave
94 YJ - 2.5 Hesco Cam B&B Ported - AX5 Trans w/Centerforce Dual Friction Clutch - 4" Rough Country Lift W/Skyjacker Shocks - D44 Rear/ARB - D30/ARB - ARB Compressor - Warn M8000 in Custom Bumper - Reunell Rear Bumper - Metalcloak 6" Body Armor Kit - Tuffy Console - 265x85-16 Tires - 2M Radio

Offline neale_rs

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #1 on: September 03, 2010, 07:40:52 AM »
I've heard of poly tanks getting a permanent dent in the bottom from hitting rocks.  Could that have happened?   In the cases I've known about, the fix was to change the tank and upgrade the skid plate.
'95 YJ, 33 x 12.5 mud tires, RE 4.5 ED lift, Atlas 4 speed, rear D44, ARBs front and rear, 4.56 gears, 8000# winch

Offline VA_YJ

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #2 on: September 03, 2010, 01:45:32 PM »
If you want to buy or fab a tank, check out Genright for ideas.  They got some nice'uns.

http://www.genright.com/category.aspx?categoryID=31
95 YJ, 31 BFG ATs, 4.0 TB & spacer, Banks header, DynoMax CAT back, 19# inj, AEM CAI, 20 gal mod, Optima yellow
98 TJ, 35 BFG Krawlers, 4.0 liter, ax15, atlas 5:1, armor, Super 88 (under construction)
96 XJ Cheep Cherokee, 33s, 4.0 liter, AW4, future project
89 Waggy, 360 V8 727 dana 44s, it runs

Offline Jeffy

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #3 on: September 03, 2010, 05:30:40 PM »
Hmm $50 vs. $200-300...  Not a tough question.

perhaps what's happening is that the tank isn't shrinking but the breather lines going back to the evap might be clogged or the valves damaged.  So the vacuum caused by the fuel pump is causing the tank to collapse a bit.  I know my tank does this to some extent since I can release the vacuum when I take the gas cap off.
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Offline sharpxmen

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #4 on: September 03, 2010, 06:13:08 PM »
Hmm $50 vs. $200-300...  Not a tough question.

perhaps what's happening is that the tank isn't shrinking but the breather lines going back to the evap might be clogged or the valves damaged.  So the vacuum caused by the fuel pump is causing the tank to collapse a bit.  I know my tank does this to some extent since I can release the vacuum when I take the gas cap off.

it's not vacuum, it is pressure. the gas cap on the newer YJs would not let pressure out (only thru the evap canister) but will allow air in - it has a built in check valve and it is tested on our smog equivalent here.
« Last Edit: September 03, 2010, 06:32:17 PM by sharpxmen »
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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Offline dwtaylorpdx

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #5 on: September 04, 2010, 12:17:02 AM »
I've ran across others reporting the same issue, and really the tank is deformed,
the bottom is bulged upward, the top is bowed downward, the sides are warped
and the tank has a bit of a twist in it!

I shortened the pickup assembly about 1/2 inch and it still does not fit correctly,
and seems to be getting worse as I let the tank sit and dry out.

I'll try and post a couple pics, its pretty obvious that something changed....

Dave
94 YJ - 2.5 Hesco Cam B&B Ported - AX5 Trans w/Centerforce Dual Friction Clutch - 4" Rough Country Lift W/Skyjacker Shocks - D44 Rear/ARB - D30/ARB - ARB Compressor - Warn M8000 in Custom Bumper - Reunell Rear Bumper - Metalcloak 6" Body Armor Kit - Tuffy Console - 265x85-16 Tires - 2M Radio

Offline sharpxmen

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #6 on: September 04, 2010, 07:06:37 AM »
I've ran across others reporting the same issue, and really the tank is deformed,
the bottom is bulged upward, the top is bowed downward, the sides are warped
and the tank has a bit of a twist in it!

I shortened the pickup assembly about 1/2 inch and it still does not fit correctly,
and seems to be getting worse as I let the tank sit and dry out.

I'll try and post a couple pics, its pretty obvious that something changed....

Dave


my return is blocked for probably the same reason, i looked under and my skid is bent just slightly - didn't get a chance to take it out and check the tank.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline dwtaylorpdx

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #7 on: September 05, 2010, 01:29:03 AM »
FYI the return line goes straight down to the bottom of the tank and there is less
than 1/8 inch between it and the tank bottom.(Assuming my estimations are correct)
when everything is right, much less when its warped.
Its a crappy design. I'm trying to figure out if I can build a insert that takes the place
of the slosh tray in the tank that would support the tank and keep the pump off the bottom.
AND that I can fit through the top of the tank.

Dave

94 YJ - 2.5 Hesco Cam B&B Ported - AX5 Trans w/Centerforce Dual Friction Clutch - 4" Rough Country Lift W/Skyjacker Shocks - D44 Rear/ARB - D30/ARB - ARB Compressor - Warn M8000 in Custom Bumper - Reunell Rear Bumper - Metalcloak 6" Body Armor Kit - Tuffy Console - 265x85-16 Tires - 2M Radio

Offline neale_rs

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #8 on: September 10, 2010, 03:01:17 PM »
Maybe a brace from top to bottom of tank would be enough without replacing the slosh tray.
'95 YJ, 33 x 12.5 mud tires, RE 4.5 ED lift, Atlas 4 speed, rear D44, ARBs front and rear, 4.56 gears, 8000# winch

Offline Jeffy

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #9 on: September 10, 2010, 04:32:23 PM »
Maybe a brace from top to bottom of tank would be enough without replacing the slosh tray.
If you're going to be welding braces then you might as well jsut build a new tank or else use a universal fuel cell.
Youtube Channel: https://www.youtube.com/channel/UCZNlr60GXH5OlKIFrT7P6mg
My Jeep: http://4bangerjp.com/forums/index.php?topic=2783.0
"If the motor car were invented today, there is absolutely no way that any government in the world would let normal members of the public drive one."

Offline neale_rs

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Re: Shrinking Gas Tank? Engine Stalling.
« Reply #10 on: September 10, 2010, 04:42:44 PM »
I was thinking along the lines of just putting a stick in there!
'95 YJ, 33 x 12.5 mud tires, RE 4.5 ED lift, Atlas 4 speed, rear D44, ARBs front and rear, 4.56 gears, 8000# winch