Fuel Pumps

[howiedodat]

I sent the below PM to a member but got no response. It has been a few days. I was hoping to not start a new thread for my question but here I am. Any thoughts and helpfull comments are welcome. Thanks !!

Hello !! I have been checking the forums for advice on fuel pumps and I see that you seem to like the mechanical, namely the Carter. I just recently switched to dual 1404 (500cfm) Edelbrock carbs on an Edelbrock Street tunnel ram on my .30 over 360 LA, 9.5 to 1, comp cam, roller rocker, headers, aluminum heads, etc. What has started to happen (the car is only weekend driven) when I attempt to start it, there is no fuel in the carbs save a "spit". I have to crank for probably 2 to 3 mins (or longer) in 30 sec intervals until I get fuel. I am assuming this has nothing to do with the carb/intake swap and is a fuel pump failing. I am about to switch to the 3/8 fuel pick up/sender and 3/8 fuel line and am concidering a fuel pump swap, thinking electric. In your opinion, is it a bad fuel pump and will a quality mech. pump be fine? Thanks !!

 

[roadrunnerman]

does it start up right away when you drive it for awhile? if so i wouldn't think it was the fuel pump.my p/u with a 360-4 does the same thing but it will sit for a month at a time b4 i drive it unless my wife needs it. it could be that the fuel is draining back out the float bowl.that is one possibility.somebody else here might have another idea.

 

[howiedodat]

Once the car has been started, it will start with barely a few seconds of crank time. Its just that intial start after sitting for more than a few days. Thanks !!

 

[b5rt]

I had the same problem on 2 cars. Swapped fuel pumps, helped one but not the other. Found the fuel line at the tank must have been porous even though it appeared okay. Replaced it and problem solved. But both cars, 69 Dodge and 70 Chrysler will lose their prime after sitting more than a few days. I think of it as a time to build oil pressure while I'm cranking it to refill the fuel line. There are small electric pumps available (jegs) that can be used as a priming pump to fill the line. I used a similar one on a GTX. Used it to prime the line, then switched it off and relied on the mechanical pump for driving.

 

[howiedodat]

Are you trying to tell me that out of all the members on this forum that NO one has an opinion as to electric vs. mechanical pumps and which ones they like ?????????

 

[WileE]

OK, here's mine. For a regular street/ mildly modified car, a mech fuel pump is fine. For a race / seriously modified car, elec is a must. Elec pumps are too noisy for a street car, unless you get a gerotor type.

 

[howiedodat]

Thanks !! Very helpfull info !!

 

[Andrew]

I was having same exact problem for a while- to the point where I had to spray ether to start it after it sat for a week. but once it ran , it would start ez all day. Though eventually I got stuck. Everyone told me mechanical pumps dont fail intermittantly, but I think mine did. I'm pretty sure eyther in the gas was f-ing up the valves inside and making them stick closed.

Anyway I'm switching to electric despite the fact it may be overkill for my build. Some benefits are less internal moving parts inside the engine and cooler fuel.

 

[howiedodat]

Thanks for the insight !! LIke you, I don't think I need electric but since I am going to swap the sender and new fuel line front to back, I wanted some ideas from the folks who have been there and done it. Learn from someone else experience, it's cheaper.

 

[Cranky]

The fuel in the lines may drain back some but the gas in the carb bowls shouldn't go anywhere and the car should start up on what's in the carb and run long enough for the mechanical pump to get the juices moving again. If the carb is going dry, you have a leak in it somewhere. The fuel inlet comes into the carb high and there's no way it can siphon out the carb if the pump lets it drain back but if the pump is letting that happen, what else is it doing? Have you sniffed your oil dip stick lately for gas fumes? Does the oil level seem to be getting higher? Years ago a buddy was all happy because his engine quit using oil.....the crankcase was keeping full because of the gas going into it lol. As for electric fuel pumps on street cars....all of my cars exhaust systems are way too loud for me to hear a fuel pump running lol

 

[scotts74birds]

I'm with Cranky here! Full float bowls should'nt go away, and make the car hard to start! If the bowls do their jobs, and the accelerator pumps do their jobs, then a tap of the loud pedal should be all it needs to start!

 

[72Satellite440]

Hey, Med Mod 440 engine, Id like your guys advise on which MECH fuel pump I should get...
-Mopar {80 gph @ 8.7 psi.}
-Holley Big Block Chrysler 110 GPH
http://www.holley.com/12-440-11.asp

Anyone use Holley-?

 

[Meep-Meep]

I have a Holley mechanical and it seems to work fine.

You are going to have to do some detective work to see where the fuel is going. Is it dumping through the main discharge when you last shut it off? When you shut it off hot look in the carbs right away.

I doubt going from 5/16" to 3/8" line will make a big difference.

 

[shag766]

fuel pump

as for not starting and touching with either to run, this is completely my opinion and opinions are like a-holes everybody has one, thats real hard on a gas engine. it was brought to market for diesel use with a much more oil base fuel. even then use sparringly.
a buddy who builds and has several hemis from mild to wild uses clay smith mech. pumps.
i just brought a car out of storage, 6-7 years and same problem to start. i put gas into carb maybe twice and away we go. my best quess is acellerator pump in carb. dried out for years.