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| Electric Fuel Pump [message #356500] |
Tue, 07 July 2020 15:16  |
GEMRECS
Messages: 34
Registered: October 2008
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I have installed a 4-9 gallon/minute electric fuel pump on the outside of the GMC M/H frame.
Where do you power this unit from? I thought the ignition switch, but the terminal the on-line video said was "hot"
all the time did not light up my test light. So what do you all do because I am out of ideas.|?
Michael
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| Re: Electric Fuel Pump [message #356519 is a reply to message #356500] |
Tue, 07 July 2020 21:32  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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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 shut down in and accident or when the engine is not running and the circuit is different 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
[Updated on: Wed, 08 July 2020 15:26] Report message to a moderator |
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| Re: Electric Fuel Pump [message #356528 is a reply to message #356519] |
Wed, 08 July 2020 10:21 |
GEMRECS
Messages: 34
Registered: October 2008
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Thanks Ken, Mighty kind of you.
Number 2 is my intent. The purpose is to help suck fuel to the mechanical fuel pump as none was getting that far. As the mechanical pump is fairly new, I discarded it as a suspect. Dropped tanks, cleaned and installed new rubber underneath.
Technically, the coach is traded to a dealer for an SOB which I am now trying to sell. So, I really only need to drive it 5-6 miles to the dealership. However from a liability standpoint and my conscience, I want to do a safe installation. I know about the tie in to the oil pressure switch which is great, but as I am not keeping the coach, have disregarded that.
I cannot find a "hot" place to get power to the fuel pump switch. Fuse box: only cigarette lighter, 20 amp fuse appears to have power all the time(is that right)? On line at ignition switch: no power where the you tube video said there should be, so I am stuck. The service dept. manager has purchased the coach from the dealer and he is aware of what I am doing.
Appreciate your advice and your "precious time" (as B. Dylan would say).
After this SOB and it's debt are gone, I probably will look for another GMC M/H. Had this one since 2001 and, of course, had Gemrecs for 7 years, so it kind of gets in your blood, even though reality is 81 years old with limited resources. Some GMC ads say everything works great. I don't believe that with the possible exception of one just restored ground up. Just saying!
Sorry to hear of your fire. At the, I think Pueblo Convention, I bought a fire extinguisher for under the hood. Its different from the ones Bounds sells. Though I removed it for this transfer, I'm sure it can be recharged and I will install it on any GMC M/H I might buy. Good advice to have one in generator compartment also, but I never did as my Onan usually didn't run, or would overheat and stop.
Michael Bozardt
1974 GMC Motorhome
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| Re: Electric Fuel Pump [message #356550 is a reply to message #356528] |
Wed, 08 July 2020 15:44 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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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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| Re: [GMCnet] Electric Fuel Pump [message #356554 is a reply to message #356550] |
Wed, 08 July 2020 16:07 |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
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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@Roadrunner.Com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Ken
Burton via Gmclist
Sent: Wednesday, July 08, 2020 1:44 PM
To: gmclist@list.gmcnet.org
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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Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Las Vegas, NV new email: B52sRule@Gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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| Re: Electric Fuel Pump [message #356586 is a reply to message #356500] |
Thu, 09 July 2020 13:33 |
GEMRECS
Messages: 34
Registered: October 2008
Karma: -1
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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?
Obviously, I am not gifted with knowledge of electrical systems and fuel flow issues either.
Thank you for helping me sort this out. I am anxious to get this done and for it to work,
Confused as ever, Michael
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| Re: Electric Fuel Pump [message #356594 is a reply to message #356500] |
Thu, 09 July 2020 15:26 |
6cuda6
Messages: 975
Registered: June 2019
Karma: -6
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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
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| Re: Electric Fuel Pump [message #356608 is a reply to message #356500] |
Thu, 09 July 2020 23:35 |
GEMRECS
Messages: 34
Registered: October 2008
Karma: -1
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Rich, Your summation is very good, except I have never been to Canada. I had hoped to make the Formula 1 race there one year, but it hasn't happened.
Drove the GMC to storage in Houston before we moved to College Station. About a year later, I went to get it and it would not start. Added fuel to the tanks but still no start. Months later, I tried again but same result. John Sharpe and Rob came to help. Don't recall what they did,, but it wouldn't start. Had it loaded on a hauls-all and transported it to College Station. Yes, I changed the carb fuel filter to no benefit. Had it towed to a local shop where it sat for months. Mechanic finally tinkered with it and said there was a "bad hose". I started it and drove to RV Station here for State Inspection. Discovered some clearance lights inoperable. Fixed those, then it would not start again. Had it towed home where it is now. I have not been working on it much since then, late 2018. There is no fuel getting to the clear filter just before the mechanical fuel pump. I have not suspected the mechanical pump because it is fairly new and worked to drive it across town, about 15 miles. I bought a cheap electric fuel pump, connected it, put the fuel line from the mechanical pump in a fuel can and it started and ran well, but the can is sitting on the ground.Question, where has the fuel gone? Tanks empty. Did it leak and pump was just sucking air? Added 20 gallons of fuel. Still nothing.Then dropped tanks, and fuel was "rusty" and found several bad hoses. Replaced all the hoses, had the tank cleaned, sanded and painted the tank tops (not the bottoms) added a couple of hybrid fuel senders (another story) and installed the tanks.
The notion to add an inline electric fuel pump is in hope that fuel will be drawn from the tanks and pushed as far as the clear filter where the mechanical pump, if operating, will pull it to the carb.
Part of my delay in working on the GMC has been time devoted to producing a hybrid fuel sender-taking parts from two units to make one. Could be done with original unit but could not find a source for the rheostat, so had to buy complete fuel pumps to get the rheostat. Jim Kanomata appears to have found a source and by simply changing the rheostat and offered at $100 each vs $200 for new fuel senders, so kind of blows my project away.
So I have a new fuel selector valve, a filter normally used with the Carter pump, then the electric pump (filter and pump on outside of frame rail) trying to decide where to power this thing from. Some say the fuse panel behind the glove box. Some say install an in line fuse for safety. Ken says power it off the selector valve. So now a decision must be made. I have removed the instrument panel trying to power it from the ignition switch on steering column, but haven't found a "hot"terminal under there (like the you tube said I would). I have fabricated an on-off switch mounted where the stolen radio goes, but should I use it? Whatever is decided will be made known to the RV service manager to whom the coach was sold shortly after I traded it in on new SOB.( Big mistake). I do not want to be held liable for the coach once I deliver it to the dealer.
Michael
[Updated on: Thu, 09 July 2020 23:44] Report message to a moderator |
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| Re: Electric Fuel Pump [message #356618 is a reply to message #356500] |
Fri, 10 July 2020 08:44 |
6cuda6
Messages: 975
Registered: June 2019
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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
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| Re: Electric Fuel Pump [message #356619 is a reply to message #356500] |
Fri, 10 July 2020 08:59 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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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
[Updated on: Fri, 10 July 2020 09:00] Report message to a moderator |
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| Re: Electric Fuel Pump [message #356621 is a reply to message #356586] |
Fri, 10 July 2020 11:41 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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GEMRECS wrote on Thu, 09 July 2020 13:33Okay 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
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| Re: Electric Fuel Pump [message #356627 is a reply to message #356500] |
Fri, 10 July 2020 14:04 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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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
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| Re: Electric Fuel Pump [message #356637 is a reply to message #356634] |
Fri, 10 July 2020 17:15 |
GEMRECS
Messages: 34
Registered: October 2008
Karma: -1
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Okay, I think I understand Ken's proposal. It took me awhile to see that the Main fuel tank is open (or the default setting) at the fuel selector valve and not powered. When the fuel selector SWITCH is moved to AUX, power is applied at the fuel selector VALVE. Components in the selector valve are actuated to "close" off the main tank and "open" the AUX tank. Thus, as long as the FS Switch is in AUX, the electric pump tied into it is operating.
Correct me if this is wrong.
I think I will make this connection, put my dash back together, add fuel and see if it works. If fuel is visible in the clear filter just below the mechanical pump, I will know the pump works. If the coach still does not start, I will replace the mechanical pump and try again. If it runs and I can drive it 5-6 miles to the dealer, it will be the service manager's problem as he bought the GMC.
On the other front, the SOB may have sold, ending that issue. When my '72 Datsun 240Z sells, I can look for another GMC, wife permitting.
Thx, everyone
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| Re: Electric Fuel Pump [message #356638 is a reply to message #356500] |
Fri, 10 July 2020 17:15 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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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
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| Re: [GMCnet] Electric Fuel Pump [message #356639 is a reply to message #356638] |
Fri, 10 July 2020 17:24 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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...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 <
gmclist@list.gmcnet.org> wrote:
> 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
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Electric Fuel Pump [message #356657 is a reply to message #356500] |
Sat, 11 July 2020 09:12 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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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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