Possible gas leak?

Armyman14 · Mar 25, 2014

So I think I may have a pretty big problem on my hands..a gas leak..down by the tank.
I was under my truck the other day messing with the torsion bars and what not and noticed that the tank was pretty wet, not like dripping profusely but it had been recently wet kind of like how a small leak would look.. Right now I'm getting 10.3 mpg and it's killing me. I expected low gas mileage with the truck(4.7L V8, 4X4 2002) maybe 13 or 14 but this 10.3 is out of control.. Occasionally my check engine light comes on and whenever I have it checked it almost always says "small EVAP leak" so a few months ago I changed the gas cap as recommended by O'Reilys, no luck. I have reason to believe my fuel pump may be going out too because whenever I fill up at the station and I first start my truck it doesn't account for the new gas!! It'll still be sitting on a quarter tank, and the overhead will still say 50 something miles til empty. But after I turn it off and back on the 2nd time the gas needle goes right up to where I filled it up to and so does the overhead calculator! I have no idea what needs to be done but I need to do it soon, I'm losing too much money by not fixing this
Thanks in advance everyone

Gecko · Mar 25, 2014

This actually makes me think even more that my fuel pump is the problem I'm having right now.

I had the same thing happen when filling up with gas. It happened a couple times but not every time and so I didn't think anything of it.

MegaMouseGW · Mar 25, 2014

I would remove the tank when empty, check around where the fuel pump/sending unit assembly is for a bad gasket. Remove the whole fuel pump/sending unit assembly, and replace. While the fuel pump/sending unit assembly is out of the truck fill the tank with water and look for any small leaks. Filling it with water might not help though if the hole is only there when the tank is pressurized (like when driving). When you reinstall the new pump/sending unit assembly make sure to use a new gasket.

earlzach · Mar 25, 2014

Armyman14 said:
So I think I may have a pretty big problem on my hands..a gas leak..down by the tank.
I was under my truck the other day messing with the torsion bars and what not and noticed that the tank was pretty wet, not like dripping profusely but it had been recently wet kind of like how a small leak would look.. Right now I'm getting 10.3 mpg and it's killing me. I expected low gas mileage with the truck(4.7L V8, 4X4 2002) maybe 13 or 14 but this 10.3 is out of control.. Occasionally my check engine light comes on and whenever I have it checked it almost always says "small EVAP leak" so a few months ago I changed the gas cap as recommended by O'Reilys, no luck. I have reason to believe my fuel pump may be going out too because whenever I fill up at the station and I first start my truck it doesn't account for the new gas!! It'll still be sitting on a quarter tank, and the overhead will still say 50 something miles til empty. But after I turn it off and back on the 2nd time the gas needle goes right up to where I filled it up to and so does the overhead calculator! I have no idea what needs to be done but I need to do it soon, I'm losing too much money by not fixing this
Thanks in advance everyone

My 03 had craked and rotted hoses somewhere under there near the gas fill area. I got the hose and changed it out and after sever restarts without a problem the fault cleared. Or you can go to an Autopart store to get it cleared after you fix it.

Armyman14 · Mar 25, 2014

The check engine light isn't really my main concern, that never bothers me but I am worried about the leak and how much money I'm losing on this truck everyday. You said you changed the hoses? Happen to have a pic?

Redtruck-VA · Mar 25, 2014

When you say the tank is wet are you sure it is gas or condensation? If it is indeed gas then you should address that problem immediately. I just had my tank down and it is a PIA. I put the truck on ramps about 12 inches tall all the way around, if you are not lowered then the truck should be high enough to slide the tank out after dropping it. I used a floor jack and had the wife jack it up as I wiggled it back into place. The pump and fuel level sensor are mounted together within the pump assembly basket. I had a fuel level sensor go out a couple years ago and do not know of a source for just the sensor. I bought a complete pump assembly to replace the original one. The quick disconnects are the squeeze type and not that bad to release. Good luck...

Armyman14 · Mar 28, 2014

Yeah thanks, I just went over to O' Reilys and they sold me a carb cleaner spray, he said I could spray them on the outside of the hoses and one spot should start bubbling, then I have found my leak

Armyman14 · Mar 31, 2014

I would say that test was ineffective because I couldn't find anything..

ImageUploadedByTapatalk1396245705.923389.jpg

ImageUploadedByTapatalk1396245724.525052.jpg

This is what I'm dealing with under there. The drippage stain looking things on the back are from the spray, they were not already there. Anyone ever tried a smoke test?

Armyman14 · Apr 25, 2014

Anyone ever tried a smoke test? My o'reilys recommend I try one of those, what exactly is that?

hemihustlin · Apr 26, 2014

A smoke test is more for checking evap leaks, and you will probably have to go to a garage for that. If you really have dripping gas and a ****** pump i would go ahead and order the fuel pump assembly, drop the tank, remove and replace while inspecting for possible leaks. Sometimes the oring where the FP sits can leak, especially when its pretty old (like 2002)

Armyman14 · Apr 29, 2014

Yeah it could be the o-ring because I know it's not a huge leak, I'm not worried about a spark under my truck and blowing up the damn thing, just worried about my empty wallet after constantly visiting the has statuon

hemihustlin · Apr 29, 2014

If you are getting poor mpgs its most likely other problems than this. If it was leaking enough to affect your milage it would be evidently dripping constantly and you could risk a fire if someone throws a butt under your truck

When was the last time you did a tune up? Spark plugs, air filter, clean tb and intake manifold, injector cleaner, new o2 sensors
Also what size tires are you running?

Possible gas leak?

Armyman14

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Gecko

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MegaMouseGW

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earlzach

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Armyman14

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Redtruck-VA

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Armyman14

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Armyman14

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Armyman14

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hemihustlin

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Armyman14

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hemihustlin

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