Electric Fuel Pump

K

Ken B

Well-known member
Oct 9, 2002
16,834
278
83
What are you trying to accomplish with that pump?
1. pump on all the time and no mechanical pump?
2. pump on only when you select it by a switch?
3. pump on only when the Aux tank is selected.

There are safety implications to assure shit down in and accident or when the engine is not running and the circuit is diff depending on which of the
above you choose.

My engine fire 10 years ago was sustained by an electric pump that stayed on due to a melted wire. It fed a constant stream of gasoline to the
existing fire.

Modern cars with electric pumps shut off after 5 seconds of the engine not running. Some also have impact switches.

Please tell us what you are trying to accomplish and we will give you a safe solution.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
The GM Howell EFI shuts the pump off if the engine stops running. I'm ASSUMING that all other EFI's do the same?
Bob Dunahugh
 
Ever body but me buys the Carter pumps. I bought a pair of Mr Gasket pumps for the 23' because Advance had them and they're a bit less expensive and
they note that they have check valves and I had excellent luck with the diesel version. You could ask Mike Btiere if they still are there and
working, they did fine all the time I had the coach. Now what JimH has to say is correct, and you can drop a GMC Unit and up and put a throttle body
injection system on the coach. However, a couple of pumps in back will keep the fuel from boiling to vapor in the August Southeast (GA FL AL) heat
without trouble. It will atomize quite well through a varying orifice at 10 PSI MAP and up even though that ain't what it's blended for. You can buy
'boat gas' pretty much anywhere except the Left Coast if you look for it. pure-gas.org will save some looking. I ran the 23' on boat gas in the
summer and whatever came out of the pump in winter without problems. The current 26' has an MSD Atomic injection setup which seems perfectly happy
with whatever I pour down it. At the last fill before parking for more than a week or two I put boat gas in because I never know how long it's gonna
sit and I don't want alcohol laced fuel to separate and corrode stuff. This worked well for me and works well for me. Your mileage will likely vary
substantially.

==johnny

--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
Ok, my suggestion because it is simple is to power the fuel pump off of the tank selector valve. No switch will be needed in the coach. When you need
to run the pump, simply switch the tanks on the dash and the pump will run. Also this way if you leave the switch on it will not stay running when
you turn off the ignition and get out of the coach.

I do not like the idea of running the pump on a switch that is connected to a circuit that is hot all of the time.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
> The GM Howell EFI shuts the pump off if the engine stops running. I'm ASSUMING that all other EFI's do the same?
> Bob Dunahugh
> _______________________________________________
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> Unsubscribe or Change List Options:
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Bob
How do you drain your tanks for storage? Do you have a separate power source to your pumps?
--
M Beam
75’ Avion
TBI EBL , 3.70 LSD and other stuff
Zuki Sidekick,
Dozier Al
 
Watched the Road Kill guys install IIRC an MSD Atomic or Holly injection system and they used a 100 micron filter at the electric pumpS “in” and
10 micron at the pumps “out” port.
--
M Beam
75’ Avion
TBI EBL , 3.70 LSD and other stuff
Zuki Sidekick,
Dozier Al
 
I can tell you what I did.

Elect pump with a cockpit switch for starting only. Once she fires I turn
off the elect pump. The mechanical pump takes over. If there is a burp
while under way I click on the elect pump. This way the elect pump is only
used for starting or in an emergency (vapor lock). I have two rollover
switches installed in series with the elect pump. If we are ever in an
accident and the elect pump is on the rollover switched should cut the fuel
supply to the engine.

Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken
Burton via Gmclist
Sent: Wednesday, July 08, 2020 1:44 PM
To: gmclist
Cc: Ken Burton
Subject: Re: [GMCnet] Electric Fuel Pump

Ok, my suggestion because it is simple is to power the fuel pump off of the
tank selector valve. No switch will be needed in the coach. When you need
to run the pump, simply switch the tanks on the dash and the pump will run.
Also this way if you leave the switch on it will not stay running when
you turn off the ignition and get out of the coach.

I do not like the idea of running the pump on a switch that is connected to
a circuit that is hot all of the time.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

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https://www.avg.com
 
That's the setup mine has. Still using the selector in front of the high pressure pump, one of the upcoming mods will be to run the pump power
through a relay run by that switch and add another pump and inlet filter. I need to have a spare on hand, and I'd just as soon have it plumbed in as
to have it in the spares compartment.

-johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
Michael first off what part of Canada you in maybe someone can help directly.....second off from what i'm getting here is the coach needs to run so
you can get it to the dealer that you traded it too BUT for some reason its not getting fuel via the mechanical pump.....so you want to add an
electric pump to feed the mechanical pump....correct?

My question then becomes:

- What makes you think/feel that the electric pump will fix this problem?
- Did you do the basics like change the fuel filter at the carb [heck take it out even to try it]
- Did you try running it directly from a gas can to see it the pump is even working as they can be installed incorrectly [yup have seen it installed
with the lever on the wrong side of the lobe and it was technically working backwards]
- if you disconnect the fuel line anywere close to the tanks and pressurize the tanks with compressed air did fuel come out?
- does it do it on both tanks or only one?

Lets get that part cleared up as it very unusual that you need both and electric and a mechanical pump working at the same time in the same
system....as a priming pump or vapor lock pump like Tom uses thats a different kettle of fish.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Ok...got a clearer picture now.

Well im going to say this and its just my opinion of course.....if you worried about liability etc dont go electric, not because it doesnt work but
because it was never made with it therefore its not certified to be there. Personally i would have made the OEM system work as it seems to me like you
have a bad pump or a major air leak from the tanks, but it sounds like you way past that now.....

I would find ign power (blower motor circuit, signal lights, reverse lights come to mind, air pump), wire in a rollover switch and maybe a pressure
switch if this is not only used for priming.

Have you thought about droping it off in a none running state and letting them fix it?
--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Here’s how Cinnabar does it. They use one of the switched IGN taps in the fuse box with in line fuse and through grommet out firewall under
passenger hood. Crosses over to drivers side and down drivers frame to near selector valve to a N/O relay contact. The wire to the selector valve is
tapped to drive the relay coil. Selecting AUX energizes relay and pump if key on.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
This is how I controlled the electric fuel pump on the 77 ELE II.

http://www.gmcmhphotos.com/photos/general-pictures/p64776-electric-fuel-pump-control.html

I have a similar setup on the stretch but with 2 in tank low pressure pumps feeding the Fuel injection high pressure pump. Still in process of the documentation and wiring.

JR Wright
Michigan

>
> Here’s how Cinnabar does it. They use one of the switched IGN taps in the fuse box with in line fuse and through grommet out firewall under
> passenger hood. Crosses over to drivers side and down drivers frame to near selector valve to a N/O relay contact. The wire to the selector valve is
> tapped to drive the relay coil. Selecting AUX energizes relay and pump if key on.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
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> Unsubscribe or Change List Options:
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> Okay Ken and Len, Will fuel pass through the electric pump if it is switched off or is there some type of by-pass needed?
> Fuel selector valve has "Main" tank and "Aux" tank positions which make no difference until the tanks are down to about 6 gallons remaining, then
> the switch to "Aux", right?
> Ken, So there is power to the valve regardless of which tank is on, right? Hence, I can connect the pump there to power it.
> Should the pump be left "on" all the time or is Len's method better? Use it to start but then switch it off so that a by-pass is needed? But how
> will this work? If the pump is switched "off" fuel doesn't pass through it, right?
>
> Michael

While the mechanical pump usually will pull fuel through a Carter P4070
I found it occasionally starved out for fuel on heavy acceleration. I installed a bypass check valve in parallel with it and solved my problem.

In the proposal I made to you would never see that problem. By wiring the fuel pump to the same circuit as the selector valve you will always have it
on when aux tank is selected and never have it on when main is selected.

A for your power question there will only be power at the valve and pump when the dash switch is set to the AUX position. The pump draws so little
current that no extra relays, wiring, etc are needed. That pumps draws less than 2 amps. I have a 3 amp fuse in line on mine, which you do not need,
and I have never blown it in over 10 years. So the pump definitely draws less that 3 amps.

As far a liability goes, if I was worried about it, I would be worried about adding a non-GM engineered electric pump.

You really need to fix the mechanical one first. An added electric pump is primarily used for overcoming vapor lock in a properly operating
mechanical pump fuel system.

I believe you have an air leak, plugged filter, or bad mechanical pump.
If you add an electric pump and have an air leak you are changing the fuel line from a suction line to a pressure line. You will then pump leaking
gas firm where ever the air leak is all over the place when the pump is turned on. If the line is leaking air on the input side of the electric pump
It will still suck air like it did before without the pump installed.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
You've seen the pictures of my solution on the 23'. Next budget buys another 55 PSI pump and I'll do the same on my injected 26'. Different filters
behiond the pumps, same in front of the tee. I have to get a teefitting for the high pressure hose and a foot or so of hose.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
Get a plain automotive relay with single pole double throw 30 or 40 amp contacts and a 12 v coil. I bought a dozen off eBay for 15 bucks shipped.
Power the relay coil with the wire going to the selector valve. Feed fused 12 volts - 10 amp for carb pumps, 15 or 20 for FI pumps - through a
turnover or oil pressure safety to the common of the relay. Run the normally closed contact to the pump serving the main tank. Run the normally open
contact to the pump serving the aux tank. Tee the pump outputs together and feed this to the line going forward to the engine.

--johnny

--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
...Tee the pump outputs together and feed this to the line going forward to
the engine.

TO THE ENGINE -- NOT a mechanical pump.
Ken H.

On Fri, Jul 10, 2020 at 6:16 PM Johnny Bridges via Gmclist <

> Get a plain automotive relay with single pole double throw 30 or 40 amp
> contacts and a 12 v coil. I bought a dozen off eBay for 15 bucks shipped.
> Power the relay coil with the wire going to the selector valve. Feed
> fused 12 volts - 10 amp for carb pumps, 15 or 20 for FI pumps - through a
> turnover or oil pressure safety to the common of the relay. Run the
> normally closed contact to the pump serving the main tank. Run the
> normally open
> contact to the pump serving the aux tank. Tee the pump outputs together
> and feed this to the line going forward to the engine.
>
> --johnny
>
> --
> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> I forgive them all, save those who hurt the dogs. They must answer to me
> in hell
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Do yourself a favor .... once you get this thing wired up the way you think it should be to get the pump making noise, check your oil level before
pumping fuel and after pumping fuel but BEFORE you start the motor......your checking the oil level just in case you have a bad diaphragm in the pump
and are putting fuel into the crankcase. As both Ken and i suspect you have an air leak and/or a bad pump and the problem could be IN the pump.

Please do this for piece of mind or you may have the most interesting 5 mile drive of your life!!! 8o
--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Safe way if you install one pump for each tank - take the mechanical pump off and blankflange the opening.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
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