PowerLossProblem - Gatsbys' Cruiser is ending the year on a good note:

I had intermittent power issues last year that I could not figure out. I tried everything fuel and ignition with no results. In a desperate attempt
I removed the carburetor and took it to Ken Fry for a cleaning. I watched as he disassembled, cleaned and checked. Everything seemed ok. When I
reinstalled the carb it ran perfectly and I have not had any issues since. I also replaced the carb to intake mani fold gasket. I don't know if it
was the gasket or something a miss in the carb. Just happy to have solved the problem.
--
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
 
Chuck Boyd is dead nuts right. I'm embarrassed, it didn't cross my mind...some mechanic I am.... :blush:

Make sure your tank is venting. A plugged vent will give you that exact problem. That is, runs fine for a while and then just acts like it's not
getting gas, bucks, won't go...Let it sit a while and it will run fine for a while...
--
Kerry Pinkerton - North Alabama

Had 5 over the years. Still have the first a 76 that will be rebodied into an art deco car hauler.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L
 
If you’re changing the lines, it can’t hurt to look at the fuel sock on the pickup. Rust in the tank can accumulate on the sock as you drive, building up even to the point of a stall. Once the suction stops, the rust flakes fall off and all seems just fine again for a while.

I usually put a couple of strong magnets on the bottom of our old cars’ tanks, but out of the path of the float arm. It helps keep the rust away from the pickup.

On one particularly rusty tank, we removed the sock and installed a transparent glass filter in the fuel line close to the tank. It was easy to spot and clean the accumulated rust out before it could continue to cause problems.

There is an old-school tank rust removal of adding a gallon of acetone and a length or two of chain, then agitating it for a while. It won’t make it shiny and new, but it does remove the loose rust scale.

Some things to consider if you end up dropping the tanks.

-Dave

>
> Chuck Boyd is dead nuts right. I'm embarrassed, it didn't cross my mind...some mechanic I am.... :blush:
>
> Make sure your tank is venting. A plugged vent will give you that exact problem. That is, runs fine for a while and then just acts like it's not
> getting gas, bucks, won't go...Let it sit a while and it will run fine for a while...
> --
> Kerry Pinkerton - North Alabama
>
> Had 5 over the years. Still have the first a 76 that will be rebodied into an art deco car hauler.
>
> http://www.bdub.net/pinkerton/
>
> '03 Fleetwood Discovery 39L
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
> Chuck Boyd is dead nuts right. I'm embarrassed, it didn't cross my mind...some mechanic I am.... :blush:
>
> Make sure your tank is venting. A plugged vent will give you that exact problem. That is, runs fine for a while and then just acts like it's not
> getting gas, bucks, won't go...Let it sit a while and it will run fine for a while...

******

Venting has never been a problem. The PO has this crapola locking cap that does not lock, it just rattles and can be taken off with no problem.
The early problem was sort of opposite of what you are saying.
I'd get gas, then take off. I'd have a speed cap, usually about 60 or less and I'd have to pull over for about 30 minutes. When I got back on the
road, it ran find until I filled up again.

Obviously, the scenario has changed, probably with the changing of different components as we found bad ones.

NOW, when I had the external gas tank connected to the engine mechanical fuel pump, I could run down the road 75 with no problem.
BUT connected to the GMC gas tanks, its different...

When on the main tank, with no electric pump assist, the float bowl will go empty and the engine stalls.
How do I know the bowl is empty? when I turn on the electric fuel pump to purge the gas line and carb, I can hear the gurgling of the gas filling the
bowl.

When on the RESERVE tank, which uses the electric fuel pump, I can get up to 55 mph before the power problems begin...

Everything is new, hose, from the front to the back to, and including, the fuel solenoid valve.

I'm sure someone might recognise these symptoms, but they are different from the source tank.

I'm just glad I can drive her again, FINALLY!
slc
--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Located in Waukegan \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center in Waukegan
 
> > Are auto parts stores selling gas lines that are not compatible with
> > today's fuels?
> > How often do the fuel lines need to be changed?
>
>
> *****
> I can answer this one.
> in 2007 they did have a hose that resisted the ethanol, but not a lot of people were aware of the problems until your hose rotted away. Seems to
> me it took a few years to do it.
>
> I am told that the hoses today are pretty much some degree of ethanol protected, but you still have to check as counter people at some
> establishments don't think about it and could sell you some of the old hose with no protection.
> Some folks have tried to circumvent the problem by putting in entirely metal fuel lines.
>
> I seem to think if you just put metal line where you cannot access it, such as above the tanks, and have hose were you can get at it, changing the
> fuel line would not be that big of a problem. Just my thoughts on that one.
>
> slc

It seems I have an answer for both of you.

Yes, parts stores ARE SELLING hose as fuel line that is not alcohol resistant in the long term. They may say it is, but that means that it will
outlast the warranty. You have to check both the manufacturer and the hose specification if you don't want to do the job over in 5 years.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
In 2010 while the GMC was on the hoist waiting for the engine to be rebuilt, I had the tanks dropped and all the fuel lines changed.

In 2014 while waiting to leave a rally I flipped the tank switch and a few moment later the coach stumbled, quit and would not restart. I had the
laptop connected and noticed the EBL was reporting very little fuel pressure. Flipped the switch back to the original tank, fuel pressure was back
and the coach restarted and drove home. Back home I dropped the tanks and found the fuel out line on the top of the tank had deteriorated, hard and
cracked after only 4 years. The hose was SAE 30R7 with a date code of 2007.

I replaced all the hose with 30R9 hose and installed steel lines above the tanks.

This spring I took it for a short rustbuster run to town and proceeded to fill her with gas. Then I noticed gas dropping just ahead of the tanks.
apparently I missed replacing a one foot piece between the selector valve and the fuel pump so on the suction side. It did not leak when the pump was
running. This time it was SAE 30R14 low permeability hose they were stocking.

So it does not take long for non-ethanol rated hose to deteriorate.

I'd drop the tanks, check for rust inside and the condition of the socks. then replace the lines above the tanks too. Put new seals on the senders
because the ethanol will eat that rubber too. Don't forget to replace the short filler hose pieces before they start leaking.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 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
 
> In 2010 while the GMC was on the hoist waiting for the engine to be rebuilt, I had the tanks dropped and all the fuel lines changed.
>
> In 2014 while waiting to leave a rally I flipped the tank switch and a few moment later the coach stumbled, quit and would not restart. I had the
> laptop connected and noticed the EBL was reporting very little fuel pressure. Flipped the switch back to the original tank, fuel pressure was back
> and the coach restarted and drove home. Back home I dropped the tanks and found the fuel out line on the top of the tank had deteriorated, hard and
> cracked after only 4 years. The hose was SAE 30R7 with a date code of 2007.
>
> When I had my hoses replaced in 2007, my hoses were in this sorry condition. I assume they were OEM
>
> I replaced all the hose with 30R9 hose and installed steel lines above the tanks.
>
> I would like to put the metal lines above the tanks. HOW DO YOU CONNECT/SEAL to the tanks?? If the tanks can be connected to metal lines
> permanently, the rubber hoses can much more easily be replaced when needed.
>
> /// CUT ///

--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Located in Waukegan \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center in Waukegan
 
I checked the sizes and measured how long I needed for each line, then I bought pre-cut lengths of the right size. I pre-bent the tubing then cut the
flare off both the tank fitting and the tube. I used compression fittings to join them, I believe 3/8" compression fittings. I put a length of old
hose over the tubing to prevent rattling against the tank and stuck them in place with gorilla tape. Search for Emery's Tech presentation (PDF at GMC
Eastern States I believe) on in-tank fuel pumps for more info on attaching the compression fittings to the fuel tank tubes.
http://www.gmcmhphotos.com/photos/fuel-tank-lines/p61891-fuel-tank-lines.html

I had issues with gas smell after fillup and weeping fuel off the top of one tank. With a tiny bit of air pressure and some soap and water I found the
vapour outlet was leaking. See the rest of my album about fixing that. I just replaced the rubbing tubing for that line rather than using steel.
http://www.gmcmhphotos.com/photos/g7006-fuel-tank-lines.html

If I recall back when the tanks were dropped in 2010, then socks had disintegrated so I replaced them at that time.


--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 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
 
> Chuck Boyd is dead nuts right. I'm embarrassed, it didn't cross my mind...some mechanic I am.... :blush:
>
> Make sure your tank is venting. A plugged vent will give you that exact problem. That is, runs fine for a while and then just acts like it's not
> getting gas, bucks, won't go...Let it sit a while and it will run fine for a while...

*****

Ok Kerry
This in some form, sounds similar. It struck me as I read this.

The original problem in 2007 was power loss at 60 and as I drove my top speed limit would slowly decrease, by the time I approached Illinois, top
speed was under 40.
ALSO, when the tanks were dropped, the inside was inspected clean but it acted like the intake was being starved from dirt blocking or plugging the
line.
I would stop at the gas station, fill up and take off. I would have the power loss. I would then pull over for about 30 minutes, head home and the
power loss would almost be gone until I filled up with gas again.

That was then.

been through all those carborators, fuel pumps, replaced the manifold(had cracks) and now the source of the problem is down to fuel source/tanks.

on the main tank it is either an air leak or pinched line because it will run the fuel bowl down and stall the engine, not even on the road.
The RESERVE tank has an electric fuel pump at the fuel solenoid valve so fuel is pushed forward. But I think it might be starved ( pinched hose? )
because I can't get over 55mph...

Now remember, I had an external gas can feeding the engine mech fuel pump and was doing 75mph with NO PROBLEM....
All filters are clean, no dirt or residue.

The problem seems obvious, just a matter of getting some ramps built and dropping the tanks to see what really is wrong.

--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Located in Waukegan \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center in Waukegan
 
> In 2010 while the GMC was on the hoist waiting for the engine to be rebuilt, I had the tanks dropped and all the fuel lines changed.
>
> X CUT X Back home I dropped the tanks and found the fuel out line on the top of the tank had deteriorated, hard and cracked after only 4
> years. The hose was SAE 30R7 with a date code of 2007.
>
> X CUT X
> I'd drop the tanks, check for rust inside and the condition of the socks. then replace the lines above the tanks too. Put new seals on the
> senders because the ethanol will eat that rubber too. Don't forget to replace the short filler hose pieces before they start leaking.

******

Are the fuel pick up hoses inside the tanks rubber??? Is there a way to make them steel? How do you seal where the metal line comes through the
tank?
With todays ethanol fuels, it seems silly not to use metal in the tank, doesn't it???

Thanks for your help.
slc
Gatsbys' Cruiser
--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Located in Waukegan \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center in Waukegan
 
There are no rubber hoses in the tank. They attach to the metal fuel pick up line which is part of the level indicator float assembly. This fits into the top of the tank with a flange and gasket that turns to seal it.

There are two hoses. One is fuel pickup. The other is a vent line.

Emery Stora
77 Kingsley
Frederick, CO

>

>> In 2010 while the GMC was on the hoist waiting for the engine to be rebuilt, I had the tanks dropped and all the fuel lines changed.
>>
>> X CUT X Back home I dropped the tanks and found the fuel out line on the top of the tank had deteriorated, hard and cracked after only 4
>> years. The hose was SAE 30R7 with a date code of 2007.
>>
>> X CUT X
>> I'd drop the tanks, check for rust inside and the condition of the socks. then replace the lines above the tanks too. Put new seals on the
>> senders because the ethanol will eat that rubber too. Don't forget to replace the short filler hose pieces before they start leaking.
>
>
> ******
>
> Are the fuel pick up hoses inside the tanks rubber??? Is there a way to make them steel? How do you seal where the metal line comes through the
> tank?
> With todays ethanol fuels, it seems silly not to use metal in the tank, doesn't it???
>
> Thanks for your help.
> slc
> Gatsbys' Cruiser
> --
> GatsbysCruise. \
> 74GMC260 Former Glacier Model style. \
> Located in Waukegan \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
> UBUNTU VOYAGER - Berzin Auto Center in Waukegan
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
There is a third hose on each tank for venting the tank during operation.
It has its own barb fitting. The two on the sending unit go to the fuel
pump and to the fill vent.

Rick "not recalling on stock tanks where that vent barb is located, but
it's definitely on top" Denney

> There are no rubber hoses in the tank. They attach to the metal fuel pick
> up line which is part of the level indicator float assembly. This fits into
> the top of the tank with a flange and gasket that turns to seal it.
>
> There are two hoses. One is fuel pickup. The other is a vent line.
>
> Emery Stora
> 77 Kingsley
> Frederick, CO
>

> >

> >> In 2010 while the GMC was on the hoist waiting for the engine to be
> rebuilt, I had the tanks dropped and all the fuel lines changed.
> >>
> >> X CUT X Back home I dropped the tanks and found the fuel out line
> on the top of the tank had deteriorated, hard and cracked after only 4
> >> years. The hose was SAE 30R7 with a date code of 2007.
> >>
> >> X CUT X
> >> I'd drop the tanks, check for rust inside and the condition of the
> socks. then replace the lines above the tanks too. Put new seals on the
> >> senders because the ethanol will eat that rubber too. Don't forget to
> replace the short filler hose pieces before they start leaking.
> >
> >
> > ******
> >
> > Are the fuel pick up hoses inside the tanks rubber??? Is there a way
> to make them steel? How do you seal where the metal line comes through the
> > tank?
> > With todays ethanol fuels, it seems silly not to use metal in the tank,
> doesn't it???
> >
> > Thanks for your help.
> > slc
> > Gatsbys' Cruiser
> > --
> > GatsbysCruise. \
> > 74GMC260 Former Glacier Model style. \
> > Located in Waukegan \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS
> FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
> > UBUNTU VOYAGER - Berzin Auto Center in Waukegan
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
 
Too All,

This is an album that I did when I redid the fuel tanks on our coach. You can see the lines on top of the tank. I only use a SAE30R9 rated hose which is a barrier type hose. It should last a long time as todays fuel will not permeant the liner.

http://www.gmcmhphotos.com/photos/g6928-fuel-tank-system-rebuild.html

JR Wright
GMC Great Laker MHC
GMC Eastern States Charter Member
GMCGL Tech Editor
GMCMI
78 GMC Buskirk 30’ Stretch
1975 GMC Avion (Under Reconstruction)
Michigan

>
> There is a third hose on each tank for venting the tank during operation.
> It has its own barb fitting. The two on the sending unit go to the fuel
> pump and to the fill vent.
>
> Rick "not recalling on stock tanks where that vent barb is located, but
> it's definitely on top" Denney
>

>
>> There are no rubber hoses in the tank. They attach to the metal fuel pick
>> up line which is part of the level indicator float assembly. This fits into
>> the top of the tank with a flange and gasket that turns to seal it.
>>
>> There are two hoses. One is fuel pickup. The other is a vent line.
>>
>> Emery Stora
>> 77 Kingsley
>> Frederick, CO
 
There are 3 basic types of Gates Barricade hose for fuel. Low pressure, high pressure fuel injection, and high pressure submersible for in tank pump
to hard line connection.
If you have simple carburated with mechanical or external electric booster pump, you want the first type. If not Barricade type it is obsolete for use
with today's fuel. These new hoses have a thermoplastic layer or "barricade". Auto parts stores are not supposed to be selling old type fuel line but
there are plenty of old spools of it they need to sell to recoup on. Old type can fail in a very short time. The first time Cinnabar dropped my tanks
they did not use the Barricade hose and the line to my Onan started weeping after about 5 years. I just had it all refone last year and had the Aux
switch controled in line pump added with fuse and relay system. Works great. I would say you simple cannot expect to drive a GMC in hot weather today
without an electric pump to feed the mechanical pump. It clears up instanly when you flip to AUX. Most erroneously concentrate on the fuel line from
mech pump to Qjet, but that tubing has pressurized fuel making it resistant to boiling. The problem is before the pump as they are not good at moving
vapor. If there is any porosity in your lines this problem is amplified. The old hose takes on "garden soaker" hose characteristics and must be
replaced.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
Please don't let fear of dropping the tanks stop you.
Logically (i.e. Diagnostic Tree), there are a bunch of little things that could likely contribute to your current issue but - just as important -
prevent other problems in the future. With winter coming on, you could do a rebuild and be ready to go before spring.
FWIW: I dropped the tanks (by myself) on mine twice. Stupidly, cut corner the first time and it bit me a few months later. I used dead man jacks first
time and those 2x4 block ramp second time (MUCH easier and cleaner).

--
Jim Gunther
www.LotusV6.com

now former owner - ;(

73 GMC-II 2600
by Explorer
 
The vent lines need to be barrier hoses as well since they will often, like every time you fill up, be full of fuel.

My line to the check valve is doing the soaker hose thing, spraying everywhere :(

________________________________
From: Gmclist on behalf of Jim Gunther
Sent: Tuesday, October 24, 2017 9:25:05 PM
To: gmclist
Subject: Re: [GMCnet] PowerLossProblem - Gatsbys' Cruiser is ending the year on a good note:

Please don't let fear of dropping the tanks stop you.
Logically (i.e. Diagnostic Tree), there are a bunch of little things that could likely contribute to your current issue but - just as important -
prevent other problems in the future. With winter coming on, you could do a rebuild and be ready to go before spring.
FWIW: I dropped the tanks (by myself) on mine twice. Stupidly, cut corner the first time and it bit me a few months later. I used dead man jacks first
time and those 2x4 block ramp second time (MUCH easier and cleaner).

--
Jim Gunther
www.LotusV6.comhttp://www.LotusV6.com

now former owner - ;(

73 GMC-II 2600
by Explorer

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