External fuel pump screaming/loosing pressure

[Ether]

Has happened twice now. New build, probably 100ish miles on it.

1/2 tank of gas, pump is making a steady high pitched sound. Fuel pressure is all over the place from 10-20’s/30’s

Edelbrock efi, single E2000 style frame mounted pump pulling from stock pickup (new, new stock tank)

Seems to do this after running for 30+ minutes. Turning off/resting seemed to remedy. I thought a non vented gas cap was the culprit initially.

My return line from the fuel pressure regulator goes to one of the vent lines on the tank. The other is capped off.

Cavitation? Dying FP? Overheating?

I have a spare pump to try, will probably start there since that is easy-ish to try.


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[lars]

A high pitched whining does probably mean that the pump is being starved. Start with the easy stuff. Check the fuel filter. I have a 100 micron filter upstream of the pump, 10 micron filter downstream. I have had crap in the tank partially clog the upstream filter. Also check fuel lines. Even thought I plumbed my system with EFI compatible hose, I had pieces in the circuits from both tanks collapse and start sloughing off the hose liner. Probably due to the stuff they sell here in California that only loosely resembles gasoline. Where does the pump live?

 

[nvrstuk]

Also could have a leak in the connections btw the pump and the pickup in the tank (sucking air).

 

[Dylan_Shaffer]

Sounds like inadequate tank venting to me. I’ve found vented gas caps don’t always provide enough airflow to keep up. Id run a dedicated fuel tank breather to the vent line that’s capped off, I did the same when I went to efi.

 

[Ether]

5/24 Update: drove it 1hr to work, issue started about 25min into the drive. Pulled over, turned it off. Pump, primary filter, and return line (rubber) are all cool to the touch. 99% sure my issue is aeration in the tank, and/or vapor lock in the fuel rail (just because how hot it was to touch yesterday). Stopped one more time, again at about 20min and runs perfect after sitting for just 4-5min.

I think I will try to move the return line, or add a hose to the return on the inside of the tank…

Something like this:

https://www.holley.com/products/plumbing_an_fittings_and_hose/fuel_system_components/fuel_cell_bulkhead_fittings/parts/166025ERL

Or this:

Amazon.com

Or?


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[76Broncofromhell]

High pressure pumps have a smaller gerotor section that spins faster to create more even pressure and still move the proper volume. They produce hardly any vacuum - and are prone to cavitation if not completely immersed in fuel. This differs from a low pressure pump which have large voids that are created when each gear section makes a rotation. These larger voids produce more vacuum and thus do a better job of pulling fuel. This is why LP pumps (like the Carter P4070) have no issue pulling fuel from the tank with a stock configuration and why high pressure pumps are almost always submerged in-tank pumps.

It's important to remember that gasoline has about 1/5 the surface tension of water meaning it's much harder to pull through a tube - which if you've ever tried siphoning water vs gasoline you would understand how much less water you get in your mouth than gas. Every OEM that ran an external high pressure pump ran an internal low pressure feeders to quell the vapor lock issue.

The point of all that is almost all high pressure only external pumps will experience vapor lock. It's not a byproduct of how your tank is vented - it's how the pump is designed. The E2000 specifically had a carb pusher pump matched to the flow rate to feed it because any loss in siphon from the sending unit will cause cavitation :

https://www.oreillyauto.com/detail/c/precision-fuel-pumps/fuel-delivery/fuel-pumps---tanks/fuel-pump/fuel-pump/83db8e3f0135/precision-fuel-pump/pfp0/e16270/v/a/5300/automotive-truck-1988-ford-f-150?q=fuel+pump&pos=5

TL;DR get a Carter P4070 to push to this pump or convert to an in-tank.

 

[Timmy390]

I've got 2 E2000's servicing 2 different EFI's and they work perfectly with stock carb tanks on both. One returns to the filler neck vent hose (Bronco 351W) and the other returns to the tank via the stock return (Samurai 1.6L and EFI from a Sidekick). Both are mounted on crossmembers middle of the tank high right next to the tank. both have a cheap inline filter pre pump and EFI filter post pump. I've ran both on and off road (not rock climbing just some hills and logging roads and through skidding areas at our hunting camp) and neither has skipped a beat even on the hottest of hot summer days here in AR.

I'm not saying it's not the pump but many many EFI applications are running a single E2000 style pump with no issues.

Where did you get the pump? I got mine at Oreillys and the other from Summit. Maybe you got a knockoff? Like the fake Motorcraft sparkplugs I bought a couple years back.....

Tim

 

[Ether]

I've got 2 E2000's servicing 2 different EFI's and they work perfectly with stock carb tanks on both. One returns to the filler neck vent hose (Bronco 351W) and the other returns to the tank via the stock return (Samurai 1.6L and EFI from a Sidekick). Both are mounted on crossmembers middle of the tank high right next to the tank. both have a cheap inline filter pre pump and EFI filter post pump. I've ran both on and off road (not rock climbing just some hills and logging roads and through skidding areas at our hunting camp) and neither has skipped a beat even on the hottest of hot summer days here in AR.

I'm not saying it's not the pump but many many EFI applications are running a single E2000 style pump with no issues.

Where did you get the pump? I got mine at Oreillys and the other from Summit. Maybe you got a knockoff? Like the fake Motorcraft sparkplugs I bought a couple years back.....

Tim

It's actually the pump that came with a Holley Sniper setup, that I then sold and kept the pump/filter for my edelbrock setup. I have no idea how much it was used or how before I got it.

I'm leaning toward an in tank retrofit, but may try another pump and different pre-filter. I also need to pull the stock sending unit and look at the filter/sock just to check it. The tank and sending unit are newish, and still look new.

 

[Ether]

Swapped out the "holley" pump for the one pictured. The one I removed is not holley branded. Drove around tonight, 45-70mph, no issues. But I still plan to mod the sender and put a Walbro 255 in the tank, also move the return or put a hose on the current vent/return down into the bottom of the tank

 

[Yeller]

I’ve done probably a 100 just like @Timmy390 describes and none have had any issues, my personal stuff gets used in dumb ways, never misses a beat till u try to drag the door handles on the ground and am under a 1/4 tank

I would lean towards the return being to a vent line as a potential issue. This time of year, you will never get vacuum in a fuel tank except maybe early in the morning, it will be making pressure