LMC EFI gas tank install

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1low4x4

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Hey guys, was wondering if anyone had used this tank before. This is an 84 short bed C 10 that was converted from carburetor to TBI and overdrive over a decade ago. Everything was taken from a 94 Chevy van.

The gas tank that was in it has developed holes. I ordered a new one, but I got the EFI style one this time. The last one was the original tank, with an original style fuel hanger, that they I guess put a fuel pump on. It’s still walked into the gas tank with the lock nut.

This one came with limited instructions, it has a hanger, and you can see on the top. The letters R for return, S, for supply, and V for vent.

The long tube is connected to the return, which doesn’t make sense to me, I would think that the fuel pump would need to be connected to the supply line and it would need to be the long one, correct?

Second, any clue judging by the pictures what thread or what type of male fitting I need to go into these female holes? I don’t know why they wouldn’t just put something you could clamp a fuel hose to. Or at least supply that if you decided to go that route.

Third, can I just get any fuel pump from the parts house for a TBI truck? Around the same year?

Thanks for any help.
 

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1low4x4

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This is the tank, doesn’t show the correct year but it’s the same thing.
 

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Redfish

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If your motor is stock or close to stock the fuel pump for a 1987 TBI will be fine. If you have a lot more horsepower there are some fuel pumps that flow more than the OE pump. If you check the Harristuning website he recommends a better pump for more horsepower and he tells you how much horsepower the standard pump can feed.
 

1low4x4

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If your motor is stock or close to stock the fuel pump for a 1987 TBI will be fine. If you have a lot more horsepower there are some fuel pumps that flow more than the OE pump. If you check the Harristuning website he recommends a better pump for more horsepower and he tells you how much horsepower the standard pump can feed.
Thanks redfish! The motor is close to stock. Flat top pistons and a mild cam but not a power house.
 

hogdaddy

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The supply line line gets the in-tank fuel pump, pick/up and a length of rubber hose I am guessing since it (filter) need to be positioned at the very bottom of tank
 
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vr1967

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I would put in a 96-97 pump in it from a Vortec equipped truck. (Ep381) It has twice the flow of the tbi (ep386) pump
 

SquareRoot

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I would put in a 96-97 pump in it from a Vortec equipped truck. (Ep381) It has twice the flow of the tbi (ep386) pump
TBI was long gone by 96. The EP381 is way too much pressure unless you have true "multiport" EFI.
 

vr1967

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TBI was long gone by 96. The EP381 is way too much pressure unless you have true "multiport" EFI.
The ep381 pump has an internal bypass spring that makes it capable of producing higher pressures, but the regulator is in the tbi unit itself, which regulates pressure from 11-18psi depending on spring color, unless they have a 94-95 454/7.4 spring, which will then make the pressure about 34psi. Pressure is set by the regulator.

Just because a pump is capable of producing the pressure doesn’t mean it will.
 
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Redfish

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I copied this from the Harris Tuning TBI website.


1. First I start with a new Fuel pump, STOCK 75lph TBI fuel pump will only support about 230hp before the fuel pressure drops like a rock. I recommend upgrading to the 1996 Vortec 155lph fuel pump which can support up to 450hp and plugs right into a factory TBI sending unit. https://www.summitracing.com/parts/ado-ep381 So I begin every project with a new upgraded pump.
 

SquareRoot

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Hey guys, was wondering if anyone had used this tank before. This is an 84 short bed C 10 that was converted from carburetor to TBI and overdrive over a decade ago. Everything was taken from a 94 Chevy van.

The gas tank that was in it has developed holes. I ordered a new one, but I got the EFI style one this time. The last one was the original tank, with an original style fuel hanger, that they I guess put a fuel pump on. It’s still walked into the gas tank with the lock nut.

This one came with limited instructions, it has a hanger, and you can see on the top. The letters R for return, S, for supply, and V for vent.

The long tube is connected to the return, which doesn’t make sense to me, I would think that the fuel pump would need to be connected to the supply line and it would need to be the long one, correct?

Second, any clue judging by the pictures what thread or what type of male fitting I need to go into these female holes? I don’t know why they wouldn’t just put something you could clamp a fuel hose to. Or at least supply that if you decided to go that route.

Third, can I just get any fuel pump from the parts house for a TBI truck? Around the same year?

Thanks for any help.
The return is the long tube. This is so returning fuel doesn't "dump" on top of the fuel level and aerate creating bubbles. The short tube on the one marked S is also correct. That is where the fuel pump will connect with a short piece of hose. That's an odd looking pickup. Normally there's a metal bracket that extends down that the fuel pump sits on (directly below the short tube). If you have factory TBI, I would get a pump for a 87-91 application. Photo attached for reference.

I'll be honest, I went from carb to Multiport EFI on a return style system. I used all factory stuff for an 87 to replace all my 85 parts. I skipped over the TBI technology so I may not be up to date on the nuances of that system.
 

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SquareRoot

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The ep381 pump has an internal bypass spring that makes it capable of producing higher pressures, but the regulator is in the tbi unit itself, which regulates pressure from 11-18psi depending on spring color, unless they have a 94-95 454/7.4 spring, which will then make the pressure about 34psi. Pressure is set by the regulator.

Just because a pump is capable of producing the pressure doesn’t mean it will.
ok
 

1low4x4

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I’m having hell finding the male fittings with barbed ends, or any other end on it to fit into these female holes. I’ve been to three parts houses, and four hardware stores, found out it’s metric not standard. I’m going to email MC . This is ridiculous that they don’t give you fittings for these to mate to something else.

I bought a fuel pump from a 96 Vortec for it.
 

hogdaddy

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Scottsdale
Engine Size
350
I’m having hell finding the male fittings with barbed ends, or any other end on it to fit into these female holes. I’ve been to three parts houses, and four hardware stores, found out it’s metric not standard. I’m going to email MC . This is ridiculous that they don’t give you fittings for these to mate to something else.

I bought a fuel pump from a 96 Vortec for it.
That will be tough to find metric but they are available. This is for 10mm and there is other sizes.
 
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