Fuel Slosh in Sumped Tank - External pump sucking air

[ULOSE2A6]

I bought a fuel tank with a sump on it but it appears that the sump was not installed properly. I am running a Weldon external pump on this and it is sucking air when the fuel gets around 5-7 gal and it sloshes around, you can see the fuel pressure fall off when driving around. When it is filled up, there are no issues.

Is there anything I can do other than ride around on full all the time? Any products that can be put in the tank?

Thanks
Shev

 

[S10xGN]

I had the same problem with my sumped tank (not Buick). I built a box for a sump, thinking it would be "better" than the usual method. Ended up losing suction (and me stranded) several times. Finally cut open the bottom, added a baffle and some foam, and sealed it up with Permatex. It's been leak-free and working great for 4 years now...

 

[chris kirk]

I had a similar problem only my car would actually cut out (shut off). I was using an Aeromotive 1000 pump with a XFI FAST system. I had a sump put in and it's great now. I bought a new gas tank from a non-turbo regal and had a sump installed. Very similar to you #5 pic. The box style sump is incorrect (pic #1). Good luck. Strange, how you don't hear more about this issue, for there are a lot of people running external pumps. Whether or not that's why I don't know.

 

[ULOSE2A6]

Thanks for the pics Russ, I may have to end up doing something similar because I am trying to run E85 as well and with the reduced mileage that fuel gives, it will be tough to keep it full or mostly full all the time.

Chris, you are right I would think that there would be more people that have encountered this problem. My sump looks like Russ's #5 pic but I suspect that there is no baffle in there and propbably open through to the tank. I have heard that if you just drill out holes in the original tank and weld in the sump over it, it would create a baffle of sorts. The foam would be the icing on the cake to keep it from sloshing around too.

Regards,
Shev

 

[fuzzyGN]

When I installed a sump on a stock tank I marked out the sump location and then used a 1" hole saw and made several holes in the tank. The remaining material acted like a baffle and worked very well. With the kick-up design of the Buick tank in the back it is difficult to get the sump low enough to use at low fule levels.

 

[TT/Ameasap]

I just sumped my tank last year. I drilled 3 or 4 2'' holes. Never had a problem.

 

[ULOSE2A6]

I suspect whoever did this sump prob cut out the metal and welded in the sump, so it has no baffle to speak of and lots of slosh. When the car starts cutting out and I fill it back up it usually takes around 12 gals to fill up so there is still roughly 5 gals in the tank that is unusable. Might have to do like Russ (S10xGN) did to make it work. For now I am trying to keep it filled up but we have only a few E85 stations where I am and a bit of a drive as well. I've been filling up gas cans as well to supplement in between top ups.

Regards,
Shev

 

[2GNS4ME]

Thanks for the thread. I need to look into a sumped tank since I run an external pump. The previous owner welded a fitting at the bottom of a NA tank which needs to go. I hear that u have to coat the inside of the tank otherwise u will have rust issues? Then I heard people had issues with the coating messing up thier pump. I keep mine filled for now until I decide

Shev

U should look into the Flex fuel sensor when u go e85. Last time Cal was in town I had him program a thumb wheel so I can switch between E70 E85 or 93. I will eventually will go with the sensor

Denny


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[Pronto]

Can you put fuel cell foam in it?

 

[ULOSE2A6]

Pronto,
I have to see how the foam would fit through the opening at the top of the tank, maybe cut some long lengths and force it in there. I have heard about the foam deteriorating over time and clogging the filters. I guess it should stay intact for a few years at least. Any idea of how much foam I would have to put in? I guess enough to cover the entire area of the tank so that the sloshing is reduced?

Denny,
I am running a Bank to Bank FAST so I am not sure I can do a thumbwheel with the Flex Fuel sensor, if I upgrade to XFI, it will definitely be something to have.

Regards,
Shev