Can I draw through the fuel pump?

Ranger289 · Apr 10, 2018

Hi all,

I've had my sbf swapped '98 Ranger on the road for several months now. I rigged up the fuel system initially just so it would be able to get me through our winter up here in the Great White North (eh). I've decided that it's time to go for something more elegant. Does anyone know if I can draw through the factory fuel pump with another one? I've already pulled the box once and I really don't want to do it again. I've already got a Carter pump picked out to run the right pressure for my carb and make the install quick and easy, and alleviate my worries about the factory pump not being enough to supply a 4 barrel Holley at full bore. If someone can answer me this question and maybe provide some insight I'd be much obliged.

This is the fuel pump I'm thinking of using.
https://www.summitracing.com/int/parts/crt-p4070/overview/

Thanks guys.

ericbphoto · Apr 10, 2018

Someone else was trying this recently. I believe that in practice, he found that the OEM pump in the tank was a restriction to flow. So, even though he had good pressure at idle, there wasn't enough flow to maintain pressure at higher loads/rpm. In other words - not a good idea.

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ericbphoto · Apr 10, 2018

ericbphoto said:
Someone else was trying this recently. I believe that in practice, he found that the OEM pump in the tank was a restriction to flow. So, even though he had good pressure at idle, there wasn't enough flow to maintain pressure at higher loads/rpm. In other words - not a good idea.

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I may have misunderstood. I assumed you are trying to avoid replacing a dead in-tank pump.

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adsm08 · Apr 10, 2018

ericbphoto said:
I may have misunderstood. I assumed you are trying to avoid replacing a dead in-tank pump.

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I believe that the OP replaced a perfectly good EFI system with a carb and now is afraid that the 40 GPH 40+ PSI electric pump won't keep up with said carb, and wants to avoid doing the work to pull the in-tank pump out when putting an out of tank electric one.

If anything the OE pump is likely to over-feed the carb without a pressure regulator and return rigged in.

ericbphoto · Apr 11, 2018

adsm08 said:
If anything the OE pump is likely to over-feed the carb without a pressure regulator and return rigged in.

Oh. That could be undesirable.

adsm08 · Apr 11, 2018

ericbphoto said:
Oh. That could be undesirable.

Right. Which can quickly turn into

Ranger289 · Apr 11, 2018

That's right. My in-tank pump currently works just fine, but the regulator I have doesn't return to the tank. When I first hooked it all up I ran a hose for a bypass but the pump didn't work properly without the bypass hose pinched right closed. I recently replaced the fuel filter and picked up a bunch of fuel pressure and flow (she was plugged right solid) so now I'm running in to fuel issues. Frankly, I'm very much considering replacing the pump with one that gives me 4-8 psi directly to just avoid all this stuff with the regulator. So you guys think the in-tank pump is too much of a restriction to run an inline pump effectively without removing it?

85_Ranger4x4 · Apr 11, 2018

It sounds to me originally your engine needed everything the in tank pump could cram thru the plugged filter so you had to have the return pinched off.

I would try the regulator again.

Loganwildman · Apr 11, 2018

The stock fuel pump with a return style regulator will support a moderate built engine. Be sure to install a fuel pressure gauge at the carb.

baddad457 · May 16, 2018

Ranger289 said:
That's right. My in-tank pump currently works just fine, but the regulator I have doesn't return to the tank. When I first hooked it all up I ran a hose for a bypass but the pump didn't work properly without the bypass hose pinched right closed. I recently replaced the fuel filter and picked up a bunch of fuel pressure and flow (she was plugged right solid) so now I'm running in to fuel issues. Frankly, I'm very much considering replacing the pump with one that gives me 4-8 psi directly to just avoid all this stuff with the regulator. So you guys think the in-tank pump is too much of a restriction to run an inline pump effectively without removing it?

Just FYI: I fed a 3 carb setup (3x2 bbl Holleys) at WOT on a 400+HP 331 for 2 miles with a 30 gal/hr 4-7 psi inline electric pump drawing fuel from the factory return line with the rubber check valve removed. It doesn't take gobs of fuel to feed a carbed motor. 30 gal/hr translates to 2 mpg at 60 mph. The problem I had using the intank EFI pump was there was no power supplied to it after cutting power to the computer

RangerFabWorks · May 16, 2018

FYI. You cannot pull fuel through the intank pump, without powering it. You can’t suck fuel through it. Best to remove the pump. Extend the pickup tube. Then use whatever pump you desire.

Can I draw through the fuel pump?

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