[GMCnet] Maiden Voyage and fuel line fail

[Adam Metzger]

Hello everyone! We took the Mighty Drednaught (working title) on her maiden voyage. The plan was a two hour trip to a state park, to camp for. A
week. We brought two cars just in case something went wrong, and so we could day trip.

I had the Onan fired up to the ac pm and the fridge running. We filled up, and noticed that the fuel pump kept overfilling, and purging gas down the
side of the coach. I finessed more gas in, as it looked like we were getting about 27 gallons. How big are these tanks?

My father in law warmed up that the gas gauge was finicky, and indeed it was. Stayed up at full for a while, started dropping to 3/4, went up a bit
again. Once it got past 3/4, it started dropping fast. We pulled into a station, and sure as sunrise there was a fuel leak.

It was coming from a hose near the filters. The hose was cut, and at one time had a hose clamp on it. I stopped filling the tank and the leak stppped.

I poked around and found another hose that looked like it could be this ones mate. But it had a bolt stopping the end, fixed with a hose clamp.

Thinking that this one should look the same, I ran into loves, grabbed some clamps and a box of bolts, and proceeded to mimic the other.
Fuel dtarted coming out of the hose again, so at this point I'm up to my shoulder in cold gasoline. I get the clamp tight, and away we go. We stop
about 20 miles down the road, agter I notice the gauge going up... and fuel is POURING from the bottom of the coach.

Thinking I had perhaps plugged a drain hose? I unscrewed the bolt, my wife insisted that we load all non driver humans and animals into her car, and
we called the trip about 40 miles from our destination.

Made it home safely, with the drip continuing until about 5 minutes after we arrived.

Did I overfill the tank, block a drain, causing fuel to vent out of the top!?

Help troubleshooting encouraged.

--
1976 Palm Beach
Austin, TX

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

[Terry]

Sounds like you have an electric fuel pump added on there somewhere and it has been bypassed and the line plugged with that bolt...or maybe the
opposite of that...or maybe the two lines were connected with a pump that has been removed and only one side was plugged with a bolt, but that doesn't
explain why you still had a leak after plugging the other end. It is possible,(very easy, in fact) to overfill these coaches by putting the fuel in
slowly and then it can get into the vapor collection system (carbon canister) which on mine is behind the RF wheel. Then fuel and powerful vapors can
come out of the filter incorporated in that canister. Give us some more info on where the fuel was dripping/pouring out (left,right,forward,back,
etc.) and the smart guys on here will do their best to help you before you take the coach apart or pull your hair out.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

[Terry]

Mine has 2 25 gallon tanks, but the most I have ever put in was close to 40 gallons and that overfilled it so it leaked out a crusty vent hose in
front of the left rear wheels. Lots of clamps and connections on these, check them all. If you have to fill it up with a can to make it leak again in
your driveway (to find the leak), be sure the furnace is OFF and the fridge is on AC power or turned off. Use a flashlight or fluorescent trouble
light, DO NOT use one of those burn-your-ass droplights with the incandescent bulb to find a fuel leak. Have seen several fires caused by those lights
when they crashed and broke the bulb on spilled fuel.

--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

[Ken Burton]

I am confused as to exactly which fuel line you are working on. There are fuel and vent lines all over that coach. Before you start trying to fix
this leak, you need to understand which lines go where and what they do.

As an example there are vent lines running to the gas fill, there are vent lines running to a fuel separator located in the left rear wheel well. The
is a line running from the fuel separator going on to the canister located behind the right front wheel. Then there are the normal fill lines and
lines running from each tank to the fuel tank selector and on to the fuel pump. There is another line between the fuel pump and the barb. Finally
there is a line en running to the ONAN. This is on a stock coach WITHOUT any PO modifications which is sounds like you might have.

Whatever you do get at least two working fire extinguishers and stand them on the ground next to where you are working. If you have a fire you will
not have time to go look for one. I know, I started mine on fire with a gasoline leak. It took 4 fire extinguishers and a garden hose to put it out.
After that, I had just under $10,000 in repairs to return it back to normal. .

For a gasoline fire, if you have a choice, get a foam type fire extinguisher. The next best is CO2. After that comes dry chemical and finally water.
Do not even bother with Halon or a halon substitute.

I went through all of the above (except halon) before I got my fire out.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Matt Colie]

Adam,

The most understandable fuel system diagram is here:
http://www.gmcmhphotos.com/photos/fuel-system/p51345-gmc-fuel-tank-diagram.html

It is easy to understand that your system has problems. All the rubber is junk and everything else is suspect.
It can all be fixed, but it will take some effort. It is, however, very much worth the effort.
(Says the guy that had his tanks down five times to finally get a funtional fuel system that yet again has a bad vapor valve.)

I will also direct you to read two threads that I started about this subject.
First is: Lifting fuel tanks when alone [message #174745] Wed, 27 June 2012 10:06
Second is: recommending high T [message #178309] Sun, 29 July 2012 21:06

Let me say again that it is worth the effort. The effort is also much less if have the coach high enough (you don't need a lift or a pit) and you
strap the tanks up and down so there is no juggling.

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

[Zhookoff, George]

Adam
I'm headed to Austin to relocate my GMC coach back to Atlanta.
I'm available to meet at your coach afternoon or evenings Monday Wednesday or Thursday week of 10/17.
My number
Four zero four eight six seven 3430.


George "I get by with a little help from my friends" Zhookoff
78 EL II
TAD Austin

[Jon Roche]

You need to make sure the onan is topped full of oil, and you have over 1/2 tank of gas. then diagnose after that is checked.


--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/

[Adam Metzger]

At the worst of it, the fuel looked to be coming out of the front of the rear tank. I'll crawl under and trace the hose that was leaking to its
source.

George, my kids were in tears last night after having to come home. We may pack up the cars and go camping anyway, so I'll let you know if we don't
leave today.

Thank you so much for the generous offer.

Now, anyone know why the Onan would just quit?

A Keyed ingnition was installed to bypass the electric start. It kicks hard when you start it, but won't crank.

[Todd Sullivan]

When you say it "kicks hard" "but won't crank" do you mean it turns over
readily but does not fire?

Sully
77 eleganza 2
Seattle

[Jerry Wheeler]

Have your fuel and vent lines been replaced?? If not and they are still
the original lines, then they will leak fuel. This means you have to drop
your fuel tanks and replace all the fuel and vent (vapor) lines. This is
what I had to do to my two coaches (I actually did it to 4 coaches, two
that belonged to friends). I used metal lines on top of the tanks so I
would not have to drop the tanks again.
JWID.
JR Wheeler 78 Royale/73 PD NC/OR

[A.]

Atom Ant wrote on Mon, 17 October 2016 09:17
> ...Now, anyone know why the Onan would just quit?...
The Onan pickup is far enough from the bottom of the rear tank that there has to be more than 6 - 7 gallons in the tank for it to run.

Don't crawl under the GMC without blocking it up. If a bag blows or a torsion bar turns loose without it being blocked up, your family will be
collecting life insurance.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."

[Adam Metzger]

I meant that there is a single solid click when I turn the key. But no worries now, cause it's working fine.

[Adam Metzger]

If I over filled the tanks, would it be possible for fuel to Come out of the top of the tank?

Would it be possible to get fuel in the filler vent line?

Fuel issues are no joke so we're grounded until I at least understand why it was happening.

[Jerry Burt]

Atom Ant wrote on Mon, 17 October 2016 11:13

> If I over filled the tanks, would it be possible for fuel to Come out of the top of the tank?

> Yes, it could be a leaking hose or the fuel gauge.

>
> Would it be possible to get fuel in the filler vent line?

> Yes, The vent lines are on top of the tanks and go to just below the fuel fill cap. Theoretically, you could force enough gas in to fill the
> tanks, the vapor canisters, and everything else up to the the top of the fill next to the driver. As far as I can tell, filling these things is kind
> of a "seat of the pants" experience. Each time is different and depends on the pump nozzle, pressure, and how you hold your mouth.

>
> Fuel issues are no joke so we're grounded until I at least understand why it was happening.

I fill slowly, and refill every 200 miles or so. Others with more experience than me will check in shortly with tips and tricks.

--
Patti & Jerry Burt
73 Gmc 26' Canyon Lands -
Photos - http://jburt.smugmug.com/GMC-Motorhome
Lots of upgrades but lots to do to make it ours.
Members: FMCA - GMCMI - GMCWS - Pacific Cruisers

[Jon Roche]

lots of possibilities for leaks. I have not seen any gmc motorhomes lately whose fuel lines actually look in great shape after any kind of storage
time. You will have to drop the tanks down and install new fuel lines to get rid of all leaks now and in the future. It is really not that tough
or super expensive of a task, if your tanks themselves are not destroyed by rust on the inside, and the senders are OK.\


start here:

http://www.gmcmhphotos.com/photos/fuel-system/p51345-gmc-fuel-tank-diagram.html

and here to see what they should look like:

http://www.gmcmhphotos.com/photos/mechanical/p34271-gas-tank-clean-up-2ffuel-line-replacement.html

--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/

[Adam Metzger]

Where is the fuel gauge located? One in each tank?

--
1976 Palm Beach
Austin, TX

[Todd Sullivan]

yes

On Mon, Oct 17, 2016 at 11:56 AM, Adam Metzger <atomm...@gmail.com>
wrote:

[Adam Metzger]

lqqkatjon wrote on Mon, 17 October 2016 13:29

> lots of possibilities for leaks. I have not seen any gmc motorhomes lately whose fuel lines actually look in great shape after any kind of
> storage time. You will have to drop the tanks down and install new fuel lines to get rid of all leaks now and in the future. It is really not
> that tough or super expensive of a task, if your tanks themselves are not destroyed by rust on the inside, and the senders are OK.\
>
>
> start here:
>
> http://www.gmcmhphotos.com/photos/fuel-system/p51345-gmc-fuel-tank-diagram.html
>
> and here to see what they should look like:
>
> http://www.gmcmhphotos.com/photos/mechanical/p34271-gas-tank-clean-up-2ffuel-line-replacement.html

This is great info Jon. Man, you guys are awesome.

When

--
1976 Palm Beach
Austin, TX

[John R. Lebetski]

By this point in time ALL coaches should be retrofitted with barrier fuel line if they have not been The old stuff is non ethanol compatible and
fails after a short time cracking and weeping fuel. A tremendous fire hazard. .
--
John Lebetski
Woodstock, IL
77 Eleganza II
Source America First

[Bruce Hart]

I help a friend who's Onan would not start. Found that the end of the fuel
hose connected under the Onan had split and broke off at the 90 degree
fitting. Fortunately we were in front of a NAPA store and replaced the
hose. Onan fired right up.
The old hose looked like some type of surgical hose as it was soft and
somewhat clear.

On Mon, Oct 17, 2016 at 7:18 PM, John R. Lebetski <gransp...@gmail.com>
wrote:

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class

[Johnny Bridges via Gmclist]

There's gas comibng out where it shouldn't. This means the tanks gotta come down. As you put them back, configures the system the way you want.
Were I to do it again, I'd put metal lines down to the side of each tank.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon

[Adam Metzger]

Hello all-

So, back from our camping trip, and looking to get some things done on the coach. I've run the engine twice for about 15-20 minutes and no fuel
leaking to be found. I placed a container under the area where it was leaking and it's empty. I'm going to take it for a spin tomorrow to see if it
happens again.

so many projects!

[Johnny Bridges via Gmclist]

Adam, leaks do not cure themselves. You have a suspect fuel system. Rather than dick about patching ang guessing, become familiar with the
diagram(s), then drop the tanks, have a look to be sure they've no holes or rust through, replace >ALL< the lines, and cease wondering. It ain't that
hard physically, though it will take up the weekend. When you're done, everything will be in alcohol proof lines and now when it quits it ain't
because of a fuel leak or air sucing in a hole in a line:) Build it back box stock and then decide do you want one or more electric pumps, outboard
filters, etc. If you're a perfectionist (I'm not) get a couple of rolls of PolyArmour line, a crimping tool, and a tubing bender, and do the whole
thing in hardline. It willo outlast your children.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon

[Jim Kanomata]

Adam,
Have you replaced ALL the 3/8 hoses?
Also the Fill hose connectors.
I'll be it will not leak again till you fill up. Also the O ring gasket at
the middle of the tank can leak when full.
If you have not replaced all the hoses and tubes, you must do it as the
ethanol is eating the old ones along with rubber in the tank selector
switch and fuel pump.

--
Jim Kanomata
Applied/GMC, Fremont,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Johnny Bridges via Gmclist]

Listen to The Guru. He's correct.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon

[John R. Lebetski]

Rubber fuel line is obsolete /non compatible with today's fuels. That said it is aged out many times over anyway. New rubber fuel line only lasts a
few years with ethanol E10 and breaks down. Only use fuel line such as Gates Barrier with the plasticized liner layer. It comes in low and high
pressure types and submersible type for those eith in tank pump applications. Fresh Barrier line should outlast all of us at this point.

--
John Lebetski
Woodstock, IL
77 Eleganza II
Source America First

[Carl Stouffer]

Atom Ant wrote on Mon, 17 October 2016 11:13

> If I over filled the tanks, would it be possible for fuel to Come out of the top of the tank?
>
> Would it be possible to get fuel in the filler vent line?
>
> Fuel issues are no joke so we're grounded until I at least understand why it was happening.

IF everything is as it should be with your fuel system, I think it is virtually impossible to overfill the tanks.

By everything being as it should be, I mean:

1 - ALL hoses, including the filler hoses, are in good shape with tight clamps

2 - the sender O-ring seals are sound and not leaking

3 - the fuel/vapor separator in the left wheel well is working properly (this will keep raw fuel from getting to the carbon canister behind the right
front wheel)

From what I understand, Rob Mueller stores his coach with the fuel topped off to the point that he can see the gas at the filler neck, and doesn't
have any leakage.

I can fill my own coach to the top and not have any fuel leakage. Fuel leaking from the bottom of the coach is NOT normal. Do as others have
suggested and drop the tanks and replace all the rubber. IT is a lot of work, but not all that difficult.

--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging

[Adam Metzger]

I will get under the coach and poke around. I still have not identified the source of the open ended hose that the initial leak was coming from.

there is a hose with a bolt hose clamped into it, sealing it. there is another hose that open ended, that you can tell at one time had a hose clamp
on it. (where the initial leak was. This is the one I blocked, thinking it needed to be blocked, and had come undone on the road. Perhaps I caused
more pressure by blocking it, thereby causing the fuel to leak from another place? (the tank?)

both are mid way down the drivers side, right next to the fuel pump.

thanks again for your patience. and keep the answers and ideas (and firm suggestions that I trust you guys because you know what the hell you're
doing) coming.

:p

--
1976 Palm Beach
Austin, TX

[Matt Colie]

Atom Ant wrote on Thu, 27 October 2016 13:44
> <Snip>

> Perhaps I caused more pressure by blocking it, thereby causing the fuel to leak from another place? (the tank?)

> :p

Adam,

Very simply, that is just not possible if everything is as it should be.

I can fill my coach so I can see the fuel in the fill neck, and the only place it leaks now is from the carbon canister because the blasted vapor
valve is screwed up - AGAIN.

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

[Jim Kanomata]

Adam,
You can spend time trying to FINGER out what is leaking, but you need to
understand that the old hoses must be replaced with the new type that can
survive the ethanal.
You will need to drop the tanks to rehose.
Any questions, call me.

On Thu, Oct 27, 2016 at 10:44 AM, Adam Metzger <atomm...@gmail.com>
wrote:

>

--
Jim Kanomata
Applied/GMC, Fremont,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Adam Metzger]

can someone remind me where I saw a list of fuel line lengths and sizes for a fuel line re-do?

Any other must haves?

[Jim Kanomata]

We have that data here we pass to people that call us.
3/8 hoes 22'
5/16 hose 33'
1/4 hose 11'
There are few other things I feel important to do at the same time to avoid
Vapor lock and also make fueling fast and easy. Just call and ask for me.

--
Jim Kanomata
Applied/GMC, Fremont,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Adam Metzger]

I've been under the coach trying to map out what the PO did so I can decide how to move forward.

I found out first that the line with the bolt in it, was about 18 inches long, and was open on the other end, connected to nothing. 8o

Some questions-

The connections on the bottom corner of each tank....these are what?
On my coach they are connected, including a t and a pump. The pump appears to run to the Onan.

There is a connection mounted to the driver side rail fore of the front wheels. Is this the selector switch?

Sorry for the seemingly dumb questions. There will be many more. :?

The diagrams in the manuals are no bueno.

[John Wright]

Adam,
Pictures are worth a thousand works.

JR Wright

[Jon Roche]

just forward of the rear wheels along the outside frame rail, was where the original selector switch was. Lots(included myself), install a pump
there as well, on the aux tank line. Usually close to that cross member. there should be a wire there that gets 12v when the fuel tank switch on
the dash is switched down to Aux.

OEM selector switch looks like this:
https://www.amazon.com/Standard-Motor-Products-FV1T-Selector/dp/B005ETOVZM/ref=sr_1_1?ie=UTF8&qid=1477927997&sr=8-1&keywords=fuel+selector+valve


Normally, the generator line runs from the top of the rear tank, to the generator, and the fuel pump for that is mounted on the side of the
generator. Those lines pop out about the rear wheel, and go toward the rear of the coach.

not going to guess as to anything else you might have going on.

--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/

[Adam Metzger]

Indeed, they are! A thousand works is what I'm in for, I'm sure. :d

Troubles with my Photobucket prevent that at the moment.

So it turns out that of the three hoses that run to the selector switch, the one running to the front of the coach is cut and blocked with a bolt.
Another is the host that is open, and the very hose that the fuel was originally leaking from to start this whole mess.
The third is running to the top of the aux tank.

This leads me to believe that the PO chose to combine the tanks? Would that explain it?

[Matt Colie]

Adam,

There were no stock connections to the bottom of the tanks - ever.

It sounds like you have a seriously cobbled mess there. There is a movement here to use the drain plugs to connect the tanks. While this may seem
convenient, my coach shows strike damage to the tanks and transmission pan that would make me worry. The other thing is the unfortunate fact that the
mod eliminates any possibility of fuel inventory management.

With the APU (generator) pulling from the bottom of both tanks, you have an opportunity unique in the GMC world. You could run the fuel down enough
to immobilize the coach just by running the generator.

Here is a link to a good diagram:
http://www.gmcmhphotos.com/photos/search.php?searchid=282701&cpage=14
I hope this is a help.

With the exception of the problems directly related to crapahol, the designed fuel system is quite effective - if it all works. Repairing it is not
an insurmountable task. It does take some determination, and I have done it all....

Matt





Atom Ant wrote on Mon, 31 October 2016 11:21

> I've been under the coach trying to map out what the PO did so I can decide how to move forward.
>
> I found out first that the line with the bolt in it, was about 18 inches long, and was open on the other end, connected to nothing. 8o
>
> Some questions-
>
> The connections on the bottom corner of each tank....these are what?
> On my coach they are connected, including a t and a pump. The pump appears to run to the Onan.
>
> There is a connection mounted to the driver side rail fore of the front wheels. Is this the selector switch?
>
> Sorry for the seemingly dumb questions. There will be many more. :?
>
> The diagrams in the manuals are no bueno.

Atom Ant wrote on Mon, 31 October 2016 12:13

> Indeed, they are! A thousand works is what I'm in for, I'm sure. :d
>
> Troubles with my Photobucket prevent that at the moment.
>
> So it turns out that of the three hoses that run to the selector switch, the one running to the front of the coach is cut and blocked with a bolt.
>
> Another is the host that is open, and the very hose that the fuel was originally leaking from to start this whole mess.
> The third is running to the top of the aux tank.
>
> This leads me to believe that the PO chose to combine the tanks? Would that explain it?


--

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

[Ken Burton]

I worked on a coach once that had the two drain ports cobbled together. The person that did this also added a piece of angle iron to cover the ports
and the line between the two tanks. While there were no marks on the tanks there sure were a lot of scratches on the angle iron.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Adam Metzger]

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

[James Hupy]

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

[Matt Colie]

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

[Ken Burton]

James Hupy wrote on Tue, 01 November 2016 12:11

> 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
>

> On Tue, Nov 1, 2016 at 9:50 AM, Adam Metzger wrote:
>
> >
> >
> > 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

[Adam Metzger]

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

[Ken Burton]

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 Henderson]

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

[Ken Burton]

Ken Henderson wrote on Wed, 02 November 2016 20:09

> 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
>

> On Tue, Nov 1, 2016 at 11:31 PM, Ken Burton wrote:
>
> > 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.