Electirc fuel pump dumb question....

[trip]

when installing an electric fuel pump - do you bypass the meachanical?
if it is mounted near the trunk - can it run into the stock mechanical, or
does that defeat the whole idea of incresing fuel pressure to the carb?
OR - does the pressure continue through the mechanical to a greater
amount, than otherwise? Help me out here............
Trip
66 HEMI
fuel starvation issues - when starting only.........

 

[Manifold]

Opinions vary, but on my setup I have a small electric and a good mechanical. I have no problems with either causing a problem for the other. My car is mostly street with some strip time.

If you just need to fill the carb(s) prior to starting, then install a small inline electric and use it to prime the system before you start it. Once started, shut off the electric and the mechanical can take care of it from there.

I also use my electric at the track to fight vapor lock. On hot days, the mechanical gets so heat soaked that I barely get into second gear before the starvation begins. Flipping on the electric before the run eliminates the issue.

I don't care for the noise of an electric, so I prefer using a mechanical most of the time. If vapor locking is an issue, a good electric pump setup should eliminate the problem.

 

[Manifold]

when installing an electric fuel pump - do you bypass the meachanical?
if it is mounted near the trunk - can it run into the stock mechanical, or
does that defeat the whole idea of incresing fuel pressure to the carb?
OR - does the pressure continue through the mechanical to a greater
amount, than otherwise? Help me out here............
Trip
66 HEMI
fuel starvation issues - when starting only.........

Just realized I didn't actually address your specific questions:

- You don't have to bypass the mechanical pump
- It can run into the stock mechanical pump
- You won't increase fuel pressure to the carb by adding an electric behind the mechanical. The mechanical is going to create the pressure it creates regardless of a small increase in pressure created by an electric between the mechanical and the tank

What is the actual problem you are trying to combat? If you are having starting issues, it's likely due to fuel evaporating in the carb(s) and the mechanical has to be cranked quite a bit to fill the carb(s) back up when starting. If you use a small electric to fill the carb(s) prior to cranking, it'll reduce the cranking time since you won't be waiting for the carb(s) to fill.

Why do you think you need more pressure to the carb(s)? 4-7lbs is plenty for the street. Any more than that and most carbs will begin having issues.

 

[trip]

Explanation of fuel pressure issue

really appreciate the help here - I have a 66 Hemi Satellite, it ran fine with the single Demon the previous owner had on it, but I was getting dissed for not having the 2 4's on it - so I did, both correct Carters and stock intake were installed - would only start when some fuel was poured into carb -
I was using the ether, but got dissed for that, (so I stopped that!)
1. Would not start - blew out lines to carb
2. Would not start - replaced shaft in mechanical fual pump
3. Would not start - replaced mechanical fuel pump
3. Was that old Carters have small reservoir, and todays gas evaporates
quickly - "just throw on an electric fuel pump and that will fix her"
Installed as told near rear shock tower, runs directly to mechanical -
Sum Bitch still will only start, then runs fine, when I pour some gas into the
rear carb - both were re-built, one by Larry Shepherd, one by Dick Katter.
I also, have a switch to turn off electrical after she is running.
ALSO - when I look into card and activate throttle linkage, I see only
small squirts of gs going in??
Trip
Bewildered

 

[Manifold]

If you've verified that you have fuel moving well through both lines to each carb (with the engine off, run a rubber line from the feed line at the carb (either do one at a time or check both at the same time) into a gas can then turn on the electric - see that you have a steady flow), I'd turn your attention to the carbs.

Were the carbs dialed in/adjusted correctly? Here's a writeup by Fugly: http://www.diamondbackengines.com/technical-white-papers/setting-up-dual-quads/

Yes, you should only see gas from the shooters when you look down into the carb and crack the throttle when the engine is off. If you're getting gas from the shooters, then you should have enough gas to start the engine. Do you get the squirting gas when the engine won't start? I'm going back to my question of were the carbs dialed in correctly.

One other question: Do you have a fuel pressure gauge at/near the carbs? I assumed no, but thought I should ask. If you do and are getting a good reading, then no need to follow the first paragraph above. Turn to the carbs...

 

[Manifold]

Also, by "small squirts of gas" do you mean that there's very little gas squirting at what appears to be under little pressure, or are they small solid streams of gas? If you're getting a weak, low volume shot of gas, then there's a problem with the accelerator pumps. Adding fuel pumps to the fuel system won't make a change here - this portion of the system is all inside the carb. If you're getting a solid, high pressure shot of gas then you're fine.

Are any of these dissers who convinced you of putting the two fours on any good with said set up? I'm thinking you need to seek out someone, who has good experience with these, who can actually look at the setup and do some troubleshooting. Doing it over the internet is pretty difficult.

 

[trip]

Understood = thanks very much, Dick Katter lives not too far, in Manassas, Virginia,
maybe he will help, the
dissers, don't know jack - they just like to see the massive Hemi air-cleaner.

 

[howiedodat]

Hello all, can you folks reccomend which "small " pumps to use for this "priming " issue ? Thanks

 

[trip]

YES - small squirts of gas - NOT long squirts - and Hemi cars worked off the rear carb, until you punch it - the front carb does no work at starting - if the accelerator linkage needs adjusting to get a long sustained "pump" - how do I do that?
no, it does not have a gauge, but has new Holly blue pump - I guess I can try
bypass the machanical, and hit the switch, then start, then turn off.
If you guys don't help me, I'll go by a Mustang. (just kidding)

 

[Manifold]

Hello all, can you folks reccomend which "small " pumps to use for this "priming " issue ? Thanks

This one physically looks just like the one I have, and mine performs at the pressure levels listed for this pump as well. If you're not getting on it, this little electric ran my 383 just fine on the street (PO had bypassed the mechanical - turned out the push rod was wore out).

http://www.summitracing.com/parts/PFS-10701/

 

[Manifold]

YES - small squirts of gas - NOT long squirts - and Hemi cars worked off the rear carb, until you punch it - the front carb does no work at starting - if the accelerator linkage needs adjusting to get a long sustained "pump" - how do I do that?
no, it does not have a gauge, but has new Holly blue pump - I guess I can try
bypass the machanical, and hit the switch, then start, then turn off.
If you guys don't help me, I'll go by a Mustang. (just kidding)

If you have a new Holley blue pump, are you running a regulator? That Holley pump is more than capable to feed your needs without the mechanical pump.

"Small squirts" is relative at this point. Without seeing it, there's no way to determine if it's an adequate pump shot or not.

So, sounds like the carb is not dry because you are able to get fuel from it. You have issues elsewhere - doesn't sound like a fuel supply problem.

Maybe you should go buy a Mustang. :tard: :tongue3: