Maiden Voyage and fuel line fail

Adam,

That is amazing. (The pictures are a real story teller.)
I am hoping that all that stuff was supported to be clear of the road.
It clearly shows a very complete lack of understanding how the fuel system is supposed to work.
It could well be that the PO had as much trouble with rubber fuel lines in crapahol as I did, but hew sure pick a dangerous way to deal with it and he
still didn't replace the fill-vent run that was a lot of my problems.

Matt
--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit
 
> Adam, The top of the heap in fuel systems seems to be with an electric pump
> installed in the tanks in each tank. The controls seem to be with a
> selector switch to power each pump separately. Eliminate the tank selector
> valve with one way check valves on each output line, followed by a single
> line to the carb or fuel injection unit of your choice. Obviously all metal
> lines instead of hoses where possible.
> Second choice is a stock hook up with Gates Barrier hoses, new selector
> valve followed by a carter 4070 electric fuel pump hooked in the auxillary
> fuel line or alternately in the single supply line to the carb or
> injection. Wire the pump to the tank selector switch and when vapor lock
> rears it's ugly head, just switch to the aux tank and supply pump. Filters
> should be made of metal, not clear plastic.
> Other variations are out there, but both of the above set ups will result
> in a trouble free fuel delivery system.
> Jim Hupy
> Salem, OR
> 78 GMC Royale 403
>

>
> >
> >
> > selector switch. You can see one of the two hoses cut and plugged. that
> > one goes forward to the engine. the other is the one that was leaking fuel.
> > the third goes to the top of the main tank?
> >
> >
> >
> > Layout of tanks as I can tell. This is the bottom view, meaning the tanks
> > are combined through the drain plugs.
> >
> >
> >
> > filter and pump. Pump goes from main tank to generator. I followed the
> > wire to the front, into the dash, under the steering wheel, where it is not
> > connected to anything, and taped. I suppose that this allowed the Onan to
> > run the main tank to the very bottom. this also explains some
> > inconsistencies I noticed with the fuel tanks while driving.
> >
> >
> >
> > initial view of under the coach. lines hanging like this.
> >
> > I plan on re plumbing this to spec.
> >
> > lets here your arguments! thoughts? Ideas? anything I should do or not
> > do while the tanks are dropped?
> >
> >
> >
> >
> > --
> > 1976 Palm Beach
> > Austin, TX
> >

I agree with Jim Hupy's recommendations but would like to add one item. Please add an oil pressure shut down switch that will automatically turn off
the electric pump if the engine is not running. They are cheap and readily available. During my engine fire the electric pump kept running feeding
the fire with additional fuel even though the engine was turned off. Mine was due to an electrical short (burned insulation) in the wiring. It made
extinguishing the fire almost impossible. You can wire it into the the ground side of the electric pump and not have to modify any of the existing
coach wiring. You simply add one extra wire and add one pressure switch.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Thanks Ken. I was looking at that very thing this evening. A stupid question, but where does an oil pressure switch wire to on the other end?
--
1976 Palm Beach
Austin, TX
 
There are several ways to wire in that switch. If you are going to use the Jim Hupy suggested method of powering the pump from the tank selector
switch, then I would not interrupt the circuit on the (+12 volt) positive side of the pump. Run one wire from the tank selector to the pump and be
done with the positive side wiring.

On the negative side of the pump, DO NOT ground it at the pump. Instead, run a single wire from the pump up to the top front of the engine. The pump
draws less than 1.5 amps so an 18 or 16 ga wire is heavy enough. Remove the existing oil pressure sender and install a "tee" to allow two senders to
be installed. Install both senders. On the new sender, wire the common side to any ground location available on the engine. Then connect the new
wire to the pump on the Normally Open side of the switch.

You are done.

You could reverse the two wires on the switch just as long as one wire is on common and the other is on the N/O contact
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Ken,

I've got one problem with your fuel pump wiring recommendation: Using the
ground as the switched protective circuit seems to me to open the
possibility of a ground short -- very likely during a fire -- leaving the
fuel pump powered. You, of all people, know the result of that. I'd much
rather have a ground fault in a protected positive circuit; at least that
should interrupt current to the pump.

Maybe I've got my head screwed on crooked, but it wouldn't let me leave
this alone! :-)

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc., etc.
www.gmcwipersetc.com

> There are several ways to wire in that switch. If you are going to use
> the Jim Hupy suggested method of powering the pump from the tank selector
> switch, then I would not interrupt the circuit on the (+12 volt) positive
> side of the pump. Run one wire from the tank selector to the pump and be
> done with the positive side wiring.
>
> On the negative side of the pump, DO NOT ground it at the pump. Instead,
> run a single wire from the pump up to the top front of the engine. The pump
> draws less than 1.5 amps so an 18 or 16 ga wire is heavy enough. Remove
> the existing oil pressure sender and install a "tee" to allow two senders to
> be installed. Install both senders. On the new sender, wire the common
> side to any ground location available on the engine. Then connect the new
> wire to the pump on the Normally Open side of the switch.
>
> You are done.
>
> You could reverse the two wires on the switch just as long as one wire is
> on common and the other is on the N/O contact
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> Ken,
>
> I've got one problem with your fuel pump wiring recommendation: Using the
> ground as the switched protective circuit seems to me to open the
> possibility of a ground short -- very likely during a fire -- leaving the
> fuel pump powered. You, of all people, know the result of that. I'd much
> rather have a ground fault in a protected positive circuit; at least that
> should interrupt current to the pump.
>
> Maybe I've got my head screwed on crooked, but it wouldn't let me leave
> this alone! :)
>
>
> Ken H.
> Americus, GA
> '76 X-Birchaven w/Cad500/Howell EFI & EBL,
> Manny Brakes & 1-Ton, etc., etc., etc.
> www.gmcwipersetc.com
>

>
> > There are several ways to wire in that switch. If you are going to use
> > the Jim Hupy suggested method of powering the pump from the tank selector
> > switch, then I would not interrupt the circuit on the (+12 volt) positive
> > side of the pump. Run one wire from the tank selector to the pump and be
> > done with the positive side wiring.
> >
> > On the negative side of the pump, DO NOT ground it at the pump. Instead,
> > run a single wire from the pump up to the top front of the engine. The pump
> > draws less than 1.5 amps so an 18 or 16 ga wire is heavy enough. Remove
> > the existing oil pressure sender and install a "tee" to allow two senders to
> > be installed. Install both senders. On the new sender, wire the common
> > side to any ground location available on the engine. Then connect the new
> > wire to the pump on the Normally Open side of the switch.
> >
> > You are done.
> >
> > You could reverse the two wires on the switch just as long as one wire is
> > on common and the other is on the N/O contact
> > --
> > Ken Burton - N9KB
> > 76 Palm Beach
> > Hebron, Indiana
> >

I have no problem with doing it either way. You would just have to run 2 wires from the switch to the pump instead of one. I do not use the +12
power to the tank selection valve on my pump so I switch the +12 side at the pressure switch, not the ground.

I was just trying to accommodate the suggested tank selection power as simply as possible.

I will agree that your solution is a safer way.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
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