Gas Tank Connections 1 or 2

Dec 6, 2014
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I have two low pressure electric fuel pumps, either one of which can feed the FiTech Fuel Command Fuel cell, that has a return to the fuel tanks for unused fuel. When fuel tanks are full I get a gas smell in the cab, I guess from the full gas tank getting all the 6# return venting from over pressure. The gas cap is new. I believe this is caused from returning the fuel to the full rear tank when drawing from the front tank. Is there any reason not to have either pump capable of drawing from both tanks at the same time? The pressures will then equalize at the suctions of the pumps. I rarely worry about running out of fuel as I don’t let the levels drop that far.

Jon Darcy
aces4nrg
 
Long steep hills might uncover one of the pick ups when the tanks are less than half full, allowing that pick up to suck air.

Les Burt
Montreal
'75 Eleganza 26'

>
> I have two low pressure electric fuel pumps, either one of which can feed the FiTech Fuel Command Fuel cell, that has a return to the fuel tanks for unused fuel. When fuel tanks are full I get a gas smell in the cab, I guess from the full gas tank getting all the 6# return venting from over pressure. The gas cap is new. I believe this is caused from returning the fuel to the full rear tank when drawing from the front tank. Is there any reason not to have either pump capable of drawing from both tanks at the same time? The pressures will then equalize at the suctions of the pumps. I rarely worry about running out of fuel as I don’t let the levels drop that far.
>
> Jon Darcy
> aces4nrg
>
>
>
>
> _______________________________________________
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Check your vapor system.
Most leave the vapor hose disconnected from the base of the throttle body.
If you do not understand the system, ask us as we can help or complain the
smell.

On Fri, Aug 9, 2019 at 4:33 AM Les Burt via Gmclist
wrote:

> Long steep hills might uncover one of the pick ups when the tanks are less
> than half full, allowing that pick up to suck air.
>
> Les Burt
> Montreal
> '75 Eleganza 26'
>
>
> > On Aug 9, 2019, at 6:52 AM, Jon Darcy via Gmclist <

> >
> > I have two low pressure electric fuel pumps, either one of which can
> feed the FiTech Fuel Command Fuel cell, that has a return to the fuel tanks
> for unused fuel. When fuel tanks are full I get a gas smell in the cab, I
> guess from the full gas tank getting all the 6# return venting from over
> pressure. The gas cap is new. I believe this is caused from returning the
> fuel to the full rear tank when drawing from the front tank. Is there any
> reason not to have either pump capable of drawing from both tanks at the
> same time? The pressures will then equalize at the suctions of the pumps. I
> rarely worry about running out of fuel as I don’t let the levels drop that
> far.
> >
> > Jon Darcy
> > aces4nrg
> >
> >
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Darcy,

Just because the pump pressure is rated at 6psi does not mean the return line is pumping the fuel tank up to 6psi internally.

I would check hose connections on the top of the tanks for leaks. I had a leak at the vapour hose connection on one of my tanks that caused the same
issue. It leaked fuel but only when the tank was full.

See my photos on dropping the tanks and my leaky vapour hose connection here.

http://www.gmcmhphotos.com/photos/g7006-fuel-tank-lines.html

JWID
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
If you have gasoline smell in the cab after refueling, I would suspect the
large rubber hose that connects the filler neck to the manifold that fills
the tank, and the 1/2 inch rubber vent hose that goes up to the filler
neck. They are frequently loose as well as deteriorated.
Jim Hupy
Salem, Oregon

On Sat, Aug 10, 2019, 6:42 AM Bruce Hislop via Gmclist <

> Darcy,
>
> Just because the pump pressure is rated at 6psi does not mean the return
> line is pumping the fuel tank up to 6psi internally.
>
> I would check hose connections on the top of the tanks for leaks. I had a
> leak at the vapour hose connection on one of my tanks that caused the same
> issue. It leaked fuel but only when the tank was full.
>
> See my photos on dropping the tanks and my leaky vapour hose connection
> here.
>
> http://www.gmcmhphotos.com/photos/g7006-fuel-tank-lines.html
>
> JWID
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>