electric fuel pump with stock gas tank

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cboutinduster73

cboutinduster73

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Hi guys, I have installed a electric fuel pump and the filter with the stock tank just above the rear hosing, but no pressure build up ? Any ideas what is my problem ?

I have Jegs electric fuel pump kit with filter and all 8AN braided hose from front to back. Everything is new, do I need to prime the pump first to be able to get pressure and fuel at carb....

Thanks for your help.
 
cboutinduster73 said:
Hi guys, I have installed a electric fuel pump and the filter with the stock tank just above the rear hosing, but no pressure build up ? Any ideas what is my problem ?

I have Jegs electric fuel pump kit with filter and all 8AN braided hose from front to back. Everything is new, do I need to prime the pump first to be able to get pressure and fuel at carb....

Thanks for your help.
Click to expand...

dumb question: do you have enough gas in it? When i did mine, i had trouble maintaining pressure because the gas was too low. Especially with the car in my driveway

 
I think there is alot of gas in the tank, I also raise the back of the car. What is the best way to prime the pump ? And do you think the pump will stay primed ?
 
I'm sure the lifting may be the issue. I have my external pump mounted in the rear of the tank under the rear tire well. That way it's level with the bottom of the tank and ran a hard line around the driver side to the factory pickup that I modified and added a return line too. The factory pickup supply line 90* up towards the floor out of the tank. I gentle persuaded it to turn towards the drivers rear tire to avoid having to lift the fuel any more than needed.
 
Pump has to be mounted lower than the tank, yours looks to high.
 
Not sure what a "Jegs pump" is. They don't make pumps, just sell many types. I don't know what "just above the hose" means. Is this is a low-pressure carb fuel pump, maybe the little square rattler type? Photos really help with questions posed like this.
 
I did this with a comp 140 pump. I had to pressure my tank with air to prime the pump. As long as it stays primed it works great. I carry a piece of hose and a wad of plastic to stuff in the neck so i can blow in my tank till it picks up fuel if I ever run out.
 
Here couple of pictures of my fuel pump and installation. Hope that will help...
 

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When it comes to pumps it's location. Most are better at pushing rather than pulling.So the closer it's located to the fuel the better. And yes the pump being higher than the fuel is a problem.
 
Hard to tell from the photos, but it looks like the pump might be in danger of getting smacked by the rear axle.

IS THAT FILTER on the inlet, and is it rated for inlet use? A suction side filter must have MUCH less pressure drop than a supply side filter.

My EFI pump looks like the one posted by Magnum dust. I managed to shoehorn it into the cavity in front of the right rear wheel spring hanger, up against the floor. So it's protected by the frame. I know many guys put "big pumps" back by the rear bumper, mostly using add - on sumps, etc.

You could prime it, but what happens if you ever run out of fuel?
 
I'm far from an expert, but here are my thoughts:

1. I agree with someone above, that location looks like you're gonna smack the pump with the axle.

2. I ran that type of pump when my car was carb'd. My understanding is that holley sells their pumps(that don't quite meet the holley specs) to summit/jegs to rebrand and sell. I had mine mounted in the engine bay and it never had issues, other than being painfully loud.

3. 8an is a large hose, did you buy a pump that may be too weak for that size of hose?

4. Would not be a bad idea to pull the filter and try to see if it still has the trouble.
 
Like some of you said, I think the pump is to high, I will tried to prime it, but I think the best solution will be to come back with a mecanical pump.

Any suggestion of brand and model of mecanical pump ? I have around 400 hp under the hood.

Thank you all.
 
"Thinking."

Don't guess find out why. Hell it might be as simple as a restriction in the suction side of the pump.

Might be as simple as an AIR LEAK on the suction side
 
I had that same radial vane pump on my 65 Newport for years, though mine had the Holley Blue label. I used it to supply a Holley Pro-jection, upgrading the relief spring to 18 psi. Mine was slightly lower than the tank, in front of the leaf spring. I also question the inlet filter. You need a full flow type, usually with a much bigger diameter. I don't know if those pumps will suck fuel up well. A Walbro will.
 
You need to mount the pump lower. You should move it regardless because looking at your pictures- 1 good bump or a speed bump too fast & the rear end is gonna smash the thing to bits! Make sure the pick up in the tank isn't sucking air or is rotted.
 
that looks similar to my carter pump , and that has to be mounted with the fittings up and motor down, as well as lower than fuel level. Additionally , is that a compression fitting at your supply nipple off the sender? Could very well be sucking air at that point. As mentioned previously, I would definitely relocate that pump away from moving parts. Good luck.
 
The pump looks like a Bosch style efi pump, it is backwards. They typically have high pressure output, to about 100 psi, so not really good for carb. While the pressure can be regulated, the system will not be efficient, and will heat fuel.

I have used several in EFI projects including turbos. There is an inlet fuel filter with 13mm (1/2") connection to input side of pump, with a 8mm (5/16") filter inlet to connect to tank outlet. As others suggest the pump needs to lower. Early Mopar 2.2L Omni Turbo used a Bosch external, then converted to in-tank. It was mounted ahead of the wheel housing on passenger side on lower inner frame rail. A similar A-body location would be near front spring hanger, not sure if room exists.
 
Thanks guys, I have primed the system and everything is working ok now. I have filled up the filter and the pump started to work correctly. Now it is time to tune the car. :razz:
 
KitCarlson said:
The pump looks like a Bosch style efi pump, it is backwards.
Click to expand...
Probably mixing up the photos. magnumdust shows his pump setup (not OP), which appears to be a Walbro pump. The Bosch pumps (VW, Audi, M-B, BMW) have a bigger diameter, and a check-valve Banjo output fitting. Walbro did make one of their thin pumps for those Euro app's. If you want to use one (as I did), the only place to buy the matching Banjo fitting I found is a Delorean site (used same pump).

Other tech notes. You can use an EFI pump for carb applications. It is happy flowing at 5 psi output pressure, and will deliver a lot more flow there. Of course, you need a return tube to the tank, and can probably get by without a pressure regulator since the carb can run off the normal drop in many return plumbings. You can install the EFI pump in the engine bay, off the lower frame rails. I did that in 2 cars so far and works great, though most don't believe that.
 
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