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Old 07-16-2019, 07:21 AM   #1
L79_Acadian
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EFI question

Hi all, it's been a while.
I have a Fitech to install on the small block in the 71 GMC truck
I am at a loss as to use a frame.mounted pump, a in tank pump
or a surge tank at the front of the truck. Fabrication isn't a problem,
nor is welding aluminum. I kinda like the simplicity of a in tank pump,
but I am wondering about the pump noise. Has anyone else ev
had the I tank pump, and how noisey is it?
Thanks
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Old 07-16-2019, 08:33 AM   #2
Aus69c20
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Re: EFI question

I used a surge tank mounted to the chassis under the bed floor.
It’s fed from the in cab tank by a low pressure pump and feeds the efi high pressure fuel. A return line goes back to the surge tank from the efi and a return from the surge tank back to the in cab tank. I can run it to almost empty without fueling issues.
I didn’t like the idea of having a surge tank in a hot engine bay and potential ramifications of a frontal collision. Having said that I still have an in cab tank, so take that for what it’s worth.
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Old 07-16-2019, 08:35 AM   #3
Katrina/10
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Re: EFI question

Are you keeping the tank in the cab?
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Old 07-16-2019, 09:13 AM   #4
Janz99
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Re: EFI question

I've used both in tank and inline (frame mounted) pumps in the past and prefer the in tank because of how quite they are. A surge tank/pump would probably be just as quite but it adds a slight amount of complexity to the system.

If your keeping the tank in the cab, it may be tricky to get a pump in there. If your moving to a rear mounted tank you can modify or buy one setup for an internal pump. My truck uses a blazer tank mounted in the rear. I bought a universal hanger assembly and modified the tank to suite. Its been flawless and the pump is big enough that I have room to grow.

-Ryan
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Old 07-16-2019, 03:44 PM   #5
Ekliptix
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Re: EFI question

I've had good luck using my factory in-cab tank, with an external electric fuel pump along the frame rail, into my Holley Sniper EFI kit. I can provide a diagram and pictures if you want.
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Old 07-17-2019, 09:38 AM   #6
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Re: EFI question

I am working on a FiTech install now. I have an Edlebrock fuel sump that will be installed in the engine bay. I'm not running with it yet, but it should a little quieter than a standard electric pump, and does not need the high pressure return line. If you any questions, jyst yell!

Jim
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Old 07-17-2019, 11:29 AM   #7
MARKDTN
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Re: EFI question

I have done an '88 F150 pump in the rails. In the Ford application it had a low pressure pump in the tank and this one in the rails. I installed it in a Corvette with a TPI retrofit. So it is roughly level with the middle of the tank (with bottom draw). It has never had any problems and has been running 15 years or more. If there is any way to do it, I would put it in the tank if I was you. '80s S10 2.8 TBI Blazers have a tank with internal pump that fits pretty well behind the axle in a SWB. You can use the stock TBI pump, a TPI pump, or an LT1 pump depending on what pressure you need.
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Old 07-17-2019, 11:49 AM   #8
L79_Acadian
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Re: EFI question

Hi again, ok, I have a few options. I want to keep the stock tank right now.So, I can take out the stock sender, install a electric pump on the end of the pickup,and install a fitting in the stock sending unit lid for a return line ( that would need to be installed). Or i can take.the stock tank out, weld a fitting in the bottom of the tank to feed.the.pump and a fitting in the top for a return then install a frame mounted pump. Or construct a surge tank,plumb and feed it.from.the mechanical pump on the engine,the either put a pump in the surge tank or frame mounted pump to feed.the Fitech.
Humm, what should i do?
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Old 07-18-2019, 12:53 AM   #9
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Re: EFI question

Not sure if you missed my mention above using the stock tank, or if your 71 has no return line. If you need a return, you can consider tapping into the rubber filler neck inside the cab.

Here's what I did to use my in-cab tank with an external fuel pump.


Entire process here: http://67-72chevytrucks.com/vboard/s...d.php?t=755926
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Old 07-18-2019, 07:39 AM   #10
Aus69c20
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Re: EFI question

I fitted a return line through my existing sender.
I figured it was easier than pulling the tank to put fittings into it and less risk of blowing myself up.
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Old 07-18-2019, 05:30 PM   #11
Big Kev-O
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Re: EFI question

I too modified my fuel sending unit by upsizing the return to 3/8" and using the existing 5/16" as a return.

I attempted to braze in the stainless 3/8" with solder but ended up using silvaloy (courtesy of work). Solder wouldn't stick to the sender. Took the sock filter off the 5/16 and reamed it out for the 3/8" feed.

The FiTech inline pump has a humming noise which you can notice when the truck is idling but it's not too bad. My truck came with 50 series delta flowmasters and the just about cover the sound. I wouldn't use the inline pump unless you have performance exhaust to cover the sound. I'm cool with it.
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Old 07-19-2019, 12:34 AM   #12
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Re: EFI question

All good choices, and I've heard ekliptx run in his videos, sounds fantastic! The main reason I went FiTech was because I have two tanks, and easier to split the return line...
Tough choices!
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Old 07-19-2019, 07:11 PM   #13
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Re: EFI question

I run a stock in cab tank with my fitech and I have used both in line (frame Mount) and In tank fuel pumps , I used a old in tank fuel pump I had laying around to see if it would work I attached it to the pick up tube. It was definitly very quiet ,but I did have slosh issues below a 1/4 tank , the external frame mount pump does make a lot of noise but works well , as far as return line fitech sells a bulk head fitting that easly is put in to any tank for the return line , I also used 72 style sending unit because it has a vent and you need to properly vent this tank when routing a return lin back in to it. in the picture the return bulk head fitting supplied by fitech is to the left , I also recoment that your pump feed line after the pump weather you go in tank or frame rail pump is done in hard line not efi hose . I hate the noise and will return to the intank pump when I get a chance to figure out the the slosh issues.
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