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  #1  
Old 03-06-2017, 08:35 AM
JackDurham JackDurham is offline
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Another gas tank thread - TBI

1988 Grand Wagoneer, engine and fuel system are stock, except that I installed a Howell TBI with external fuel pump.

The problem: When the tank is half empty or less, the vehicle can sputter or cut off when I brake "kind of" hard, for example when a light turns red at the wrong time. As it gets below half empty, I have to baby the vehicle to avoid this problem in any kind of traffic.

The temporary workaround: Keep the gas tank above half full. Meaning I basically have a 10-gallon capacity and need to fill up every ~120 miles or so.

The desired situation: Able to run the vehicle to almost empty, burning say 18 gallons before needing to fill up.

Ideas I'm considering mainly involve a tank swap. But I'm open to any solution that solves the problem. Except returning to the carb, I'm not doing that.

- I've read online that a Suburban 42-gallon tank will fit if I remove the current tank and the spare tire hanger. This is my #1 idea right now. Has anyone else done this? What are all the steps and pitfalls? How hard would it be to make it work (at least "pretty much work") with the original dash gauge?

- Also I think there's a 30-gallon Bronco tank some people have used. Is there a reason to pick one over the other, aside from the 12-gallon difference? For example, does one hang lower than the other, or work better with the in-dash gauge, or allow you to keep the spare tire hanger?

- Does anybody make a tank that's similar to the original tank except with an internal baffle or tank-within-a-tank design that would solve my problem without extensive modifications?

Thanks
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  #2  
Old 03-06-2017, 09:20 AM
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babywag babywag is offline
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Aerotank makes custom fuel tanks.
Or you can stuff an in tank fuel pump inside tank like I did on my '88.

I'd examine your sending unit first, sounds like the sock/pickup is missing inside your tank?
My '90 has external pump, and I can run it down to fumes w/o issue.
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  #3  
Old 03-06-2017, 02:21 PM
JackDurham JackDurham is offline
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I emailed aerotank a few days ago, coincidentally just got the reply.

Quote:
#1923A 33 Rep. takes the place of factory tank, hard to install but fits in same location.
Tank cost with all parts and skid plate and EFI set up $ 745.00 + shipping
you will need to supply your own fuel pump we do not sell them.

#1924 29 gallon replaces spare tire with this tank. This is the new trend, remove front tank and put this tank on back. Less risk of high centering your Jeep
Tank cost with all parts and skid plate and EFI set up $ 645.00 + shipping

My first thought is, that's way more expensive than the Suburban tank idea. I can get the Suburban tank for $145 plus shipping. I was hoping the entire project would be a few hundred dollars.

My second thought is, they probably do make it a lot easier, though, by including the whole fuel injection setup (minus pump) and a new skid plate.
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  #4  
Old 03-06-2017, 09:00 PM
yossarian19 yossarian19 is offline
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Check this stuff out.

It's sort of a fuel sponge that you can set up in any old fuel tank & pickup that will keep the pump from sucking air during short (or even kinda long) off-kilter situations.

I betcha you pick the largest fuel mat you want to spend the money on, set it up right, you're done with these issues and you get to keep your spare in place.

I think the S10 2-door blazer tank is supposed to work in the factory tank location, though it does lose some fuel capacity vs the OEM. Google will help you more than I can on that one.
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  #5  
Old 03-07-2017, 06:10 AM
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mdcptman mdcptman is offline
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A sump tank might fix your problem with very little money outlay or work. I have heard many people with this problem when they use an electric pump, usually as a result of a efi conversion. A sump tank is a small tank placed low between the main tank and the pump. It will keep a reserve of fuel for when enertia pushes the gas away from the fuel inlet for a few seconds, so the pump have a continuous supply of fuel. I've seen plans of people making one out of a large section of pipe. A small primer pump can also be used to keep it full.
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Old 03-07-2017, 07:24 AM
yossarian19 yossarian19 is offline
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Ahh! Yeah! I forgot about that...
My old man uses a 2.5 gallon pancake type air compressor tank below the main tank in his Corvette w/ EFI swap. Works great. 2.5 gallons is a lot bigger than needed but that doesn't hurt anything.
I hadn't though of using pipe but that'd work, too. 2" pipe with caps on both ends, drill & tap the caps for fittings, attach to frame rail on the low pressure side & burp the air out of it. Could even use a petcock installed mid-pipe for a purge.
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Old 03-08-2017, 08:43 AM
JackDurham JackDurham is offline
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The sump idea seems great. So simple but I can't think why it wouldn't work. So basically where the line comes out of the back of the fuel tank, just have the line connect to a small tank, then have the small tank connect to the line that continues on to the fuel pump. Gravity will keep the small tank full of gas. My gauge will still go crazy when I brake but the car won't cut off. Am I understanding it correctly?
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Old 03-08-2017, 08:56 AM
yossarian19 yossarian19 is offline
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Yeah, that's about it.
The gauge can be settled down with a properly sized capacity soldered into the gauge circuit to settle down the tank sloshing effect. Google something like "corvette fuel gauge capacitor" for a better explanation than I'm prepared to give.
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Old 03-08-2017, 09:28 AM
JackDurham JackDurham is offline
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Would I need to rig a way to vent air in the sump tank? For example, a second connection between the sump tank and the main tank, this one connecting to the main tank up high to give air somewhere to go when it refills? Or am I overthinking?

Thanks!
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  #10  
Old 03-08-2017, 09:34 AM
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babywag babywag is offline
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sump won't really fix it if the problem is missing sock/pickup problem.
I'd look @ sending unit before adding a sump.
A sump shouldn't really be needed.
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  #11  
Old 03-08-2017, 02:58 PM
JackDurham JackDurham is offline
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Team Grand Wagoneer sells a replacement sender w/sock for $60 or so. Or just the sock for $8. If I traveled back in time to 1987 when my 1988 GW rolled off the assembly line, put the Howell TBI on right then and drove it on half a tank, would I have the braking fuel delivery problem? If the new sock and/or fuel sending unit would fix it, that would definitely be the cheapest and easiest way, I'm just unsure since TBI wasn't part of the original design.

I can't think of how the sump would NOT fix it (my system does normally provide gas to the pump, in effect, we're talking about how much gas is in the fuel line at a given time, adding a buffer amount in a small tank), but it would add complexity and failure points.

Last edited by JackDurham : 03-08-2017 at 03:23 PM.
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  #12  
Old 03-08-2017, 05:52 PM
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babywag babywag is offline
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I have thousands of trouble free miles, no braking or hard cornering fuel issues.
Like stated have run mine to empty many times.

A sump is a band-aid to cover up a fuel delivery issue.
If fuel delivery is lacking to throttle body it will be lacking to sump.
It may allow fuel to catch up, but the problem will still be there.
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  #13  
Old 03-14-2017, 01:34 PM
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mattparliament mattparliament is offline
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maybe it's time for an in tank fuel pump? I did one and it was pretty easy when I retrofitted the bronco 32 gallon pump

http://www.ifsja.org/forums/vb/showthread.php?t=168517
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  #14  
Old 03-15-2017, 05:36 PM
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PlasticBoob PlasticBoob is offline
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Check this out before anything else:

https://www.holley.com/products/fuel_systems/hydramat/
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  #15  
Old 09-07-2021, 09:19 PM
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roddiaz1 roddiaz1 is offline
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Better late than never

I know this response is like 4 years late, but for anybody with this same problem (now or in the future). I ordered a new fuel pick up for my 1989 GW which is fitted with the Holley Sniper EFI. I too was having trouble with the pick-up sock hanging half-way in the tank leaving about several gallons unused and the same sputtering/quitting symptoms. I measured both the pick-up and the tank. The tank is 11 inches deep from the lip of the sender hole. The sender is 7 inches long from the plate to the bottom of the
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