Moparts

Fuel Pumps...its hot ...fuel dries up

Posted By: Pyper70

Fuel Pumps...its hot ...fuel dries up - 09/06/22 08:05 PM

Need a bit of assistance. Its a chore to get my engine kicking over because I seldomly drive her. Just life at the moment but I do love her and want to take her out. I have a 440 with Dual 500 Edelbrocks, an Edelbrock 120gph fuel pump thats a few years old. Stock fuel tank and sending unit. It can sometimes take 20-30min of constant cranking to get enough fuel to the carbs to get her to kick over. I even use Starting fluid to get a few low charged RPMs to suck enough fuel quicker. I have the Hemi Fuel Vapor separator but I haven't installed it yet.

My question is this:

Can I install an electric fuel pump back by the axle to PUSH the fuel forward to the mechanical fuel pump and then have it go into bypass so only the mechanical is working to suck the fuel or does the electric fuel pump have to constantly be pushing? Do they even make 7psi fuel pumps?
Posted By: gold1950

Re: Fuel Pumps...its hot ...fuel dries up - 09/06/22 08:24 PM

I won't answer the best setup for your needs and preferences but I can say that they make low pressure (5-8 psi) psi fuel pumps.

You can get really good, low-pressure fuel pumps at Summit or Jegs, and if you want something fast and cheap to test your theory, you can get a low-pressure electric fuel pump (7psi) off the shelf at Autozone or Orielly.

They will have them sitting there behind the counter.
Posted By: Alaskan_TA

Re: Fuel Pumps...its hot ...fuel dries up - 09/06/22 08:46 PM

Are you using Ethanol fuel?

If so, it evaporates quicker than good gas.

I use non-ethanol in my old cars, but when one sits a month or more I'll squirt some down the carb before attempting to start.
Posted By: Cab_Burge

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 12:14 AM

I've delt with this issue for many years on my motors that have mechanical fuel pumps only, my solution to avoid cranking on the starter so much is to get some fresh gasoline and pour around 1 to 3 ounces down the front of each carb and hold the gas pedal down about 1/4 to 1/3 the way open from the idle position and keep the rpm under 2000 RPM as soon as you can control them after it starts and runs: up wrench up: scope:
Let us know your results, hopefully it will help others on here: luck:
Posted By: Dcuda69

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 01:00 AM

How long does this car sit between use? Something sounds wrong here. Mine sits 6 months at a time in winter and I never have to crank it 20 minutes to get it running. Holley carb(no choke), Carter mech pump and Ethanol premium fuel. I crank it 20-30 seconds at a time a few pumps of the pedal and it fires right off. I usually only drive it once a week in summer.....couple pumps and a quick crank and it's running. I've actually still had fuel in the bowls(evidenced by watching acc pump discharge)after sitting all winter. I'd be wondering where the fuel is going. twocents
Posted By: 2boltmain

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 01:08 AM

Originally Posted by gold1950
I won't answer the best setup for your needs and preferences but I can say that they make low pressure (5-8 psi) psi fuel pumps.

You can get really good, low-pressure fuel pumps at Summit or Jegs, and if you want something fast and cheap to test your theory, you can get a low-pressure electric fuel pump (7psi) off the shelf at Autozone or Orielly.

They will have them sitting there behind the counter.


A supplemental low cost electric fuel pump at the tank is almost standard fare nowadays with cars that only drive on weekends and the standard fuel blends. Also, these pumps mentioned are very quiet unlike the traditional Holly Blue and Red pumps.
Posted By: A727Tflite

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 01:10 AM

Check your fuel pump pushrod for wear. As the rod gets worn/shorter you lose stroke and volume.

In regards to the electric fuel pump, all you need for your situation, assuming the pushrod is ok, is something similar to the old in tank Vega pumps.

Something just to fill the bowls. Then shut it off after the motor lights.
Posted By: poorboy

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 01:35 AM

For years I ran an electric pump in the fuel line just outside of the tank, that ran to the mechanical pump on the motor without issues. The electric pump was wired to turn on with the ignition and turn off with the ignition. Turn on the key, listen for the electric pump to slow down (about 20 seconds), and start the car like it ran yesterday. Pretty much ended long starter cranking times. But, I wasn't feeding a dual quad 440 either.
Posted By: topside

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 01:49 AM

I did the supplemental electric pump on my Hemi car - meaning in addition to the standard mech pump - but that car had 1/2" fuel line.
I'd run the electric for about 30 seconds or so until I could hear it had filled the line.
A few pumps while cranking over and the car would light.
It also ran an MD6, MP distributor, and an F150 coil, which was a great addition. Headers, big cam, 11.70 car.
The car might sit for a couple weeks to over 4 months of winter.
Did a similar deal with one of my 383s - stock line, mech pump, AVS, ignition - and it didn't make much difference on that car.
I used one of those low-PSI plastic pumps, but the darn thing also leaked, so got rid of it.
The Eddy AVS2 on there now starts more quickly; I crank it maybe 30 seconds, then a couple pumps, and it lights.
Sits about the same as the Hemi car did.
My other 383, all stock, is about the same deal.
A stout 512 I had was oddly the quickest of all my Mopars to light off, but was not fat. Holley, 3/8 line, Carter mechanical pump, same ignition as the Hemi.
None of them had/have chokes. Temps typically 40s - 80s when starting.
I've never had several minutes of cranking on anything unless something was wrong.
Posted By: TJP

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 02:23 AM

Originally Posted by poorboy
For years I ran an electric pump in the fuel line just outside of the tank, that ran to the mechanical pump on the motor without issues. The electric pump was wired to turn on with the ignition and turn off with the ignition. Turn on the key, listen for the electric pump to slow down (about 20 seconds), and start the car like it ran yesterday. Pretty much ended long starter cranking times. But, I wasn't feeding a dual quad 440 either.


up mine can sit for a year, let the electric do it's thing, about 4-5 pumps, starts and dies, 2 more pumps it'll start, run on choke, droit into gear and drive away smile
Posted By: SomeCarGuy

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 04:48 AM

Did you mean to say 20-30 seconds? Minutes would mean something is bad wrong. Like a hole in a line, but you’d see that mess.
Posted By: A39Coronet

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 10:36 AM

Electric fuel pumps don't like to "pull", so the only thing it technically could do is push what's it's the line to the mechanical pump. If that's the case, the mechanical pump should already have fuel at it because the line is relatively flat horizontally. So I would just change the mechanical pump and double check length of fuel rod so you're getting full pumps. No point in trying to reinvent the wheel.
Posted By: lewtot184

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 01:56 PM

the float bowls in both my cars dry up in a few days after driving. i just use one of the fuel primer squirt bottles with some gasoline in them and fill the bowls thru the carb vents. simple and works. no extra gadgets needed.
Posted By: GTX MATT

Re: Fuel Pumps...its hot ...fuel dries up - 09/07/22 04:31 PM

20-30 minutes or 20-30 seconds?

If it takes 20-30 minutes you have another issue - check the fuel pump pushrod for wear.
Posted By: Mattax

Re: Fuel Pumps...its hot ...fuel dries up - 09/08/22 01:09 PM

I agree ^^^

Fuel to run the car is in the carburetor fuel bowls.

That fuel will lose some of its more volatile components the longer it sits. That's true for th efuel in the tank as well, but there's only one small vent and its cooler so it takes longer.

First thing to check is whether the fuel is in the bowls.
Quick check is to take the air cleaner off and and manully work ythe throttle,
You should see fuel shoot out the accelerator pump 'squirters' and the choke should want to close.

If there is no fuel shooting out, then you need to investigate whether that is because the pumps are not working or because the fuel level is too low.
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