Electric fuel pump...

[1974dodgecharger]

After talking to some folks and living out here in the desert. I told people about my first hard start in the morning or anytime first time start I have to spray starting fluid into the carb and after that she starts great even after driving for 3 hours in AZ heat she starts right back up etc...just first start issues.

I was told its becuase its so hot and dry here that the fuel is evaporating out of the bowl after letting the car sit for 12 hours or more.  There recommendation is a electric fuel pump and of course the guys who told me this here in AZ have the electric pump vs the mechanical.

So whats everyones thoughts of a electric vs the mechanical is it better?

[myk]

I have an electrical pump in mine, but in all honesty I see absolutely nothing wrong with a mechanical one.  As a matter of fact, I actually prefer a mechanical pump, but the idea of an electrical pump making my car harder to steal is what sold me on it.  If you're having trouble with your current setup, the 'carb floats may need to be adjusted or something, as it shouldn't be as difficult to start as you're saying it is.  IMO an electrical pump is just one more component that can break down on you when you're 300 miles away from home.  

Yes, I no longer have to pump the gas pedal to fill the bowls or whatever; with the electrical pump I turn on the ignition and the 'carb is primed and ready to help fire the engine in seconds; I don't even have to set my choke anymore on the coldest day that San Diego can throw at me. This applies to cold start, hot start, or any kind of scenario that would normally require pumping/priming a 'carb and maybe some swear words with a mechanical fuel pump.  

Another thing I don't like about the e-pump is the noise.  Maybe it's just my brand of pump, but I swear even if I had an open exhaust I'd still be able to hear the e-pump doing its thing as it's so freaking loud.   BBRRRRRRRRRRRRRRRRRRRRRR!

In summary I like what the e-pump can do for me, but the reliability of the mechanical pump trumps the e-pump any day of the week, and I would say that about any electrical component.  For example, I want to remove my mechanical fan and replace it with an electrical fan only; I think that would be pretty trick but for some reason I just can't trust the idea of electrical fans only.  In the 20 years of driving my Charger I've never seen a mechanical fuel pump fail, but my e-pump had to be replaced in just 200 miles.    The electrical pump CAN outperform the mechanical one, depending on how you look at it, but again I made the switch for reasons other than performance or reliability...

[1974dodgecharger]

Thx mike for sharing...seems not many folks have a epump.....just the two dudes I talked to here in az

[firefighter3931]

Electric pumps work fine as long as they are wired & plumbed-in properly. 

On a street car the best way is to run a return style regulator to keep fuel circulating which keeps it cooler. Cool fuel won't boil and vapor lock. 

In really hot climates the electric pump primes the carb by filling the fuel bowls. Remember that carbs are vented to the atmosphere (bowl vent tubes) and fuel will evaporate overnight. This is more of an issue with a Carter/Edelbrock style carb due to the fuel being contained within the main body. 


Ron

[myk]

Electric pumps work fine as long as they are wired & plumbed-in properly. 

On a street car the best way is to run a return style regulator to keep fuel circulating which keeps it cooler. Cool fuel won't boil and vapor lock. 

In really hot climates the electric pump primes the carb by filling the fuel bowls. Remember that carbs are vented to the atmosphere (bowl vent tubes) and fuel will evaporate overnight. This is more of an issue with a Carter/Edelbrock style carb due to the fuel being contained within the main body. 


Ron

I am SO getting rid of my Edelbrock when I get back to San Diego...

Ron, what sort of "return style regulator" did you have in mind?  All I have is the standard charcoal canister with the typical return line to the tank.

Thx mike for sharing...seems not many folks have a epump.....just the two dudes I talked to here in az

Don't get me wrong I think you could definitely appreciate an e-pump, but IMO you have to want it.  Your setup should be just fine on its own; there's something causing that hard-start issue...

[femtnmax]

I have an electric pump just fwd of rear axle with fuel filter between tank and E-pump.  then fuel line runs fwd to mechanical pump on engine.
Electric pump is Mallory 4110, it is quiet, works well, has internal pressure bypass.  Fine print in factory tech page says no regulator needed and they are correct.  I have several years of use and no problems at all. Mech pump is Carter street pump.
I use the electric pump to prime the carb, no crank crank on the starter needed any more.  The mech pump supplies enough fuel for street and hwy use up to about 3400 rpm depending on air/engine temp.  So mostly leave the e-pump off for town hwy use up to around 70-75 mph.
I did a similar set up on my Ford 428, using a carter electric pump, the mech pump cannot pull as well thru the carter pump so need the e-pump more often, but still works real well.

[john108]

I hope this is not a dumb question, but, the 2 pumps are in series with the electric pump feeding the mechanical pump.  If you turn on the electric pump before you start the engine, does fuel flow through the mechanical pump and vapor trap to fill the carburetor?  No bypass line around the mechanical pump??
It also appears that when the engine is running and the electric pump is off, fuel is sucked through the electric pump by the mechanical pump??

[femtnmax]

I hope this is not a dumb question, but, the 2 pumps are in series with the electric pump feeding the mechanical pump.  If you turn on the electric pump before you start the engine, does fuel flow through the mechanical pump and vapor trap to fill the carburetor?  No bypass line around the mechanical pump??

yes, the electric pump pushes thru the mech pump and primes the carb float bowls.  and yes, no bypass around mech pump.  I did not have a vapor trap, but may add that when I install the 383/432 stroker this winter.  Dont forget to have a fuel filter between the fuel tank and electric pump.  As mentioned I located the elec pump just fwd of rear axle, as low as possible as compared to the top of the fuel tank.  That way fuel stays in the line between the tank and elec pump so the pump has a "wet start" when you turn it on.

It also appears that when the engine is running and the electric pump is off, fuel is sucked through the electric pump by the mechanical pump??

Yes the mech pump pulls thru the electric pump.  It was easier to pull thru the Mallory elec pump vs the carter elec pump.  I could run at a higher engine rpm at hwy cruise on the Mallory vs the Carter.  Were talking 70-80 mph with the Mallory.   So I like the Mallory elec pump better because I can cruise at highway speeds on the mech pump alone, and it is much quieter than the carter pump.  
On some hot days, if vapor lock started to mess with the ability of the mech pump to feed the carb, then I turned on the elec pump and the v-lock would go away quickly.  That's why I have not added a vapor separator, have not needed it.

I wired the electric pump on/off switch such that the key needs to be in the "on" position to run the pump.  That way if I forget to turn the pump off, turning the key off shuts down the elec pump too.   When I did my initial research one suggestion was to add an oil pressure switch to also control the elec pump, so engine has to be running for pump to run.  This would be safer in some ways, but I did not do this, and my Vietnam pilot friend said it would be adding another point for failure.

[fy469rtse]

I think all of us with the mechanical pump have this cold start problem,
I have used on past cars cheap facet pump wired to crank  or start on key, pump goes open when not in use and used to help mechanical pump and prime carb fuel in and bowl, immediate improvement on cold start, pump in action only on cranking so if you don't have return line won't over power needle and seat in carb and flood.

[john108]

Thank you
Very good information to know.
John