Thinking about switching up my fuel system - in-factory-tank pump?

[joeydurango]

I've been running my '72 4x4 with a 5.3 for about 6000 miles now. I love it. One thing I don't love is the external Walbro pump. I'm running the stock in-cab tank (no problems there) with a gravity feed out the bottom to the Walbro 255 mounted on the frame rail. Pretty standard. However, the pump is annoyingly loud (can even hear it over the Magnaflows at 25mph in town) and when I'm driving through, say, Moab in July, it positively screams. I can't help but think the pump will die on me sometime at the worst possible moment.

So I'm thinking about going to an in-tank pump. I have no issue with the in-cab tank and don't want to relocate. Has anyone here successfully run an in-tank high-pressure pump in a modified factory tank? How about some sort of sump/baffle system to allow running the tank below 1/4? And if someone's done this, is a behind-the-seat in-tank pump really quieter and more reliable than an external pump?

I swear I've seen at least one version of this, but I can't turn it up on the search. I must be using the wrong keywords. Or, I dreamed it!

[ls1nova71]

I have a frame mounted Walbro pump gravity fed out the bottom of my factory in cab tank too and with stock (read quiet) exhaust, I can't hear my pump at all. I think there are a lot of knock off Walbro pumps being sold, especially on ebay, that are super loud. I have a buddy that put one in the tank of a 59 wagon and it's real loud. But to answer your question, if you think it's loud now, put it in the in cab tank and it will drive you crazy! I had a buddy who did it, he just mounted the pump to the stock sender and put it through the stock sender opening, and although it worked perfectly fine, it was loud.

[tinsoldier]

I have an external pump with the insulation mounted on the passenger rail. I can't hear it at all. The only thing I hear is the gas return when my tank is near empty. Here is the same pump I used. http://www.ebay.com/itm/Walbro-GSL39...a7de24&vxp=mtr

[Matt Cramer]

Originally Posted by joeydurango

So I'm thinking about going to an in-tank pump. I have no issue with the in-cab tank and don't want to relocate. Has anyone here successfully run an in-tank high-pressure pump in a modified factory tank?

I managed to stick a 255 lph Walbro in my fuel tank using a kit for a '94-'97 Mazda Miata, of all things. Only modification to the tank was running the wires through the sending unit.

How about some sort of sump/baffle system to allow running the tank below 1/4?

Haven't really figured out that yey. Mine has fuel starvation issues when cornering with a low tank.

And if someone's done this, is a behind-the-seat in-tank pump really quieter and more reliable than an external pump?

Unsure on the reliability part, but you've got a fuel pump sitting right behind your back. It's pretty noisy.

All in all, I've found that putting a fuel pump in the stock tank was an interesting exercise to see if it could be done and see how easy it is to put a high pressure pump in a carbed tank, but would be a better mod for something that had the fuel tank underneath.

[joeydurango]

Thanks for all the replies! While the noise of the pump bugs me a little, mostly it's just that all the noise makes me think the pump isn't long for this world. Maybe I'm being paranoid? I always hear about external pumps being failure prone, and cooling the pump by immersing it in the tank seems like a good idea...

Matt, I also have starvation issues under 1/4 with the current setup. Was considering building a quart-size "cache tank" under the gravity feed to act as a sump, but after thinking about all that, started thinking maybe the internal route would make more sense in the long run. Not, however, if I can't figure out baffles/sump/something thing else.

LS1, was it you that built some sort of a sump into the bottom of a stock tank? Or am I thinking of someone else?

And TinSoldier, that is the same exact pump I have. It was quiet for the first 1000 miles or so. The last 5000 it's been consistently whiny. I got my Walbro from Summit, so I trust it's a real Walbro. Never know though!

[ls1nova71]

Originally Posted by joeydurango

LS1, was it you that built some sort of a sump into the bottom of a stock tank? Or am I thinking of someone else?

Yes, that was me. I have a little over 15k on it now and it's worked great!

If you are worried about your pump dying, buy a spare and put it in the glove box along with enough tools to replace it, that way you will probably never need too! I actually carry a spare in my '33 Ford, and "knock on wood" I have never had to use it.

[joeydurango]

I need to look up that sumped tank again. Which build thread?

And yep, I already have a spare pump under the seat with all my tools... we think alike.

[Marty68]

post #145 i will be "stealing" many of ls1novas ideas. http://ls1tech.com/forums/conversion...-c-10-a-9.html

[joeydurango]

Awesome Marty, thanks!

[mattcrp1]

Has anyone used the Edelbrock universal sump? Would that work for your application?

[joeydurango]

I looked at that for a while, but my mechanic friends seemed a bit freaked out by that much fuel sitting in the engine compartment. I still kind of think it's a cool idea. Anyone here actually used one?

[Robznob11]

Don't know why your so dead set against relocation, I have a pull out 2002 camaro tank, in the frame rails behind the axle and it s not that hard to achieve. It can be done with a drill/hole saw and a grinder and cut off wheel. But my torch mad real quick work of it. Oh I have 90$ in the tank and pump. And another 40$ in the feed and return lines. Just saying

[Marty68]

robsnob do you have some pictures of your tank installed. car-part.com shows a tank for $60. how is filler neck installed? I haven't started modding my in cab tank yet.

[Matt Cramer]

It looks interesting, but unlike a Walbro fuel pump, I can't picture squeezing that sump through the factory fuel sending unit location.

And cutting and re-sealing a hole is not something I'd want to do with an in-cab tank. If you can't seal it 100% perfect, the cab is going to smell very strongly of gasoline.

[Robznob11]

Originally Posted by Marty68

robsnob do you have some pictures of your tank installed. car-part.com shows a tank for $60. how is filler neck installed? I haven't started modding my in cab tank yet.

I will get you some this eve, you have to drill a hole through the frame for the filler , move the rear most brace back to the end of the frame, and notch the bottom of the frame rail some, my filler will be mounted in the bed floor, when I put it in. I used two aluminum straps from Lowe's to hold it in place. And bought a 25' roll of coated 3/8 fuel line from auto zone, for cheap to run my lines.

[joeydurango]

Matt, that Edelbrock sump actually sits in the engine compartment. It's fed low-pressure fuel to keep the sump full, then sends high-pressure to the intake.

Rob, I just like the tank where it is. That's it. Thanks for the idea - which I've heard and read about many times - but I have a trailer hitch and exhaust running through the area you're talking about and I don't see any reason to move the tank.

I may just go with the under-floor cache tank/sump idea, since no one's saying external pumps are just begging to die on you...