I THINK I AM THROWING IN THE TOWEL

Did the mechanics replace the carb with q-jets? If so, are they the
correct ones for the 74 motorhome? What is the brand of the electric fuel
pump and do you have the spec of the pump (pounds of pressure and volume.)?

On Mon, Jul 27, 2020 at 7:14 PM John R. Lebetski via Gmclist <

> Yes if chain is lose or skipped it will be a dog at all times and have a
> very distinctive sound like a sick duck when you get on it. The Qjet will
> wail with little increase in speed. . If it pulls then goes flat it’s a
> fuel issue. If you kill the ignition when it goes flat then see if there
> is gas in carb via pump squirt we can accomplish the diagnosis without
> even getting finger nails dirty
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
 
GatsbysCruise wrote: "OK so at a full stop, engine running, brakes on. the engine runs at good idle, strong, no missing. Press the accellerator down,
the engine will raise the RPM normally, no missing, strong climb until it reaches that 20- +, when it get to that point, the power loss happens. But
if the RPMS go down, the engine smooths out and I press the pedal, the engine reves up to the point where the power loss occurs. then repeat the above
again."

Well, that's darn near classic fuel starvation, I'd say. But one more thought emerged from the fog. It MIGHT be bad gas. When the tanks were
"cleaned", did you or anyone double-check there was NO water or other foreign liquid in them before re-installation? A little water causes much
grief, especially with ethanol-blend gas. The ethanol is only tenuously mixed with the gasoline. If it finds water, it will part company from the
gas, and mix happily and tightly with the water, which also abhors gasoline. The two will dance about the floor of your gas tank{s} in a barely
flammable blob, occasionally being sucked into the fuel line. You can run a vehicle on alcohol (they do it in Brazil and on some race tracks), but it
takes roughly twice as much fuel as with gasoline. (ie: If your car gets 30mpg on gas, to run on alcohol you must re-jet, and get ~15mpg.)

Years ago, on the first cross-country trip with our GMC, we filled up in a small town in Pa, apparently getting some bad gas. Even after another 3000
miles on that trip, it still would cough and gasp erratically under load. Symptoms persisted intermittantly for about two years.

In any case, the suggestions made herein to set up a totally independent temporary fuel supply would eliminate this possibility. FWIW, I once ran The
Dancing Bear using a 5 gallon gas can on the floor, with a hose to the mechanical pump, just to get home. (The Smoking Lamp was definitely OUT.)
This would eliminate everything but the mechanical pump, steel line, and carb inlet filter. Easy test to try.

HTH,

Rick Staples
--
Rick Staples, '75 Eleganza, Johnstown, CO

"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
 
We are all just guessing. We, including me, have not seen this coach when it is failing. This time he had to tow it home. So does he have another
/ different failure on top of everything else he has had go wrong in the past? On top of that, I feel he has had some bad advice and possibly shoddy
work done in the past. So when he says this or that was replaced, it may be true, but was it done correctly with good quality parts. So even the
past "repairs" are suspect to me. So when we give him a single solution, I suggest that this is probably a multiple failure problem.

So what is the solution?

I suggest that everything done in the past is suspect and canned solutions from certain vendors and shops are not appropriate here. When they do
canned solutions they are just guessing too.

What is need here is to start all over and DIAGNOSE the problem(s) before attempting a "repair". ASSUME nothing done in the past was done correctly
with good quality parts. I'll bet you can not find a new fuel pump that was not made in China or East Asia. Even some Mexican parts are suspect.

So start diagnosing from the beginning and assume nothing. Sometimes replacing a small part like a filter is a good diagnostic move but replacing
carb, or alternator, isolator, etc. without proving it is a the problem is bad is a move. These type of shops that do this are simply parts guessers
and parts swappers. When "the fix" does not fix the problem, the customer is stuck with a bill and a still faulty coach.

I know of one case where a GMCer spent one week at a GM dealersship going through this crap with multiple parts replacements. Finally A GMCer stopped
by on an week end and replaced the carb fuel filter. The coach ran fine after that and he left the dealership. One week chasing chasing a clogged
fuel filter.

So diagnose.. Diagnose.. DIAGNOSE.. FIRST before repairing and assume nothing done in the past is good.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Good point Ken as this could something as simple as the carb fuel filter installed backwards....

As i said in the begining....check your fuel pressure....20$ vacuum gauge with fuel pressure option off of Amazon.....should be in everyones tool for
that matter.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Please post a link to the " 20$ vacuum gauge with fuel pressure option off
of Amazon".

Thanks
bdub

On Tue, Jul 28, 2020 at 4:49 AM 6cuda6--- via Gmclist <

> Good point Ken as this could something as simple as the carb fuel filter
> installed backwards....
>
> As i said in the begining....check your fuel pressure....20$ vacuum gauge
> with fuel pressure option off of Amazon.....should be in everyones tool for
> that matter.
>
 
Exactly. The fickle finger of fate is pointing at the filter socks in the
tanks. Those were a big part of the fuel delivery problem on my coach when
I bought it. (17 years ago).

The tank valve can be leaky even when it seems fine. Hence Chuck’s
suggestion to clamp off on of its inputs.

Rick “losing power under load always suggest fuel delivery to me” Denney

On Sun, Jul 26, 2020 at 4:56 PM Charles Boyd via Gmclist <

> Sir: a couple of things that have worked for me on occasion. Blow shop
> air back into the tank with fill cap off a couple of good bursts to clear
> the
> pickup. If still having problems use a small c clamp or engineers clamp
> to clamp off auxiliary fuel line at switching valve in case valve isn’t
> closing off properly and sucking air from aux tank. On our coach the
> filters were staying clean because the pickups were stopped up and not
> allowing any dirt or much fuel thru. After blowing shop air in tank all
> sorts of brown stuff started showing up in filter in frame rail and we
> started running at truck speed without electric pump on.
>
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
 
"" On our 1300 mile trip home when we bought our current GMC we experienced multiple instances just like what you are describing.
The reason for our problem was the filter in the carb and the can filter down by the electric fuel pump. I had to change both
multiple times on the way home. We do not have a mechanical fuel pump just the electric pump. It might not be filters in your case
but something is restricting the flow of fuel. ""

YES, it seems.
The original problem, a fuel restriction, appeared when the tanks were dropped and hoses replaced by that shop. This is a KNOWN danger.

We added a electric fuel pump so I was able to fuel from the RESERVE tank ONLY and was getting up to 70 mph no problems. I had gone 75 mph on a test
run with no power loss, I FOOLISHLY THOUGHT I HAD A TEMP FIX TO GET TO A PLACE TO HAVE THE TANKS DROPPED AND HOSES CHANGED TO FIX THE FUEL
RESTRICTION.

I was wrong I guess.l

This last fatal trip ran at 65mph for about an hour or so then the fuel restriction showed up again. This time it didn't go away.

In the past we have changed and cut open, the fuel filters, I have one at the sol fuel valve and one before the Mech fuel pump, and the carb fuel
filter, and we never found anything in them. The one time we found the Carb Fuel Filter packed with rust was when the Mech Fuel pump had rusted
internally. The rust flowed with the fuel, actually got by the CarbFuelFilter and destroyed the carborator too.

I don't know yet but I am suspecting whatever is bad with the tanks/hoses involved, got worse.

I will begin the saga again soon.

My immediate thought is to get my external gas tank out again, with a electric fuel pump and bypass the Mech fuel pump to feed the carborator. If
this works, I will probably run it this way for some crucial mileage testing and then to hustle to a shop to drop the tanks and changeout the hoses.

At least that is my plan with fingers crossed.
It sux when your toys don't work well.

slc

--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center
 
> slc,
>
> You've gotten LOTS of advice, most of it good, some excellent. I'm goint
> to tell you what I'd do:
>
> First I'd be sure the electric fuel pump is OFF. Then I'd disconnect and
> plug the short rubber coupling between the fuel tank supply line and that
> leading to the mechanical fuel pump, thereby disabling all of the GMC's
> fuel system. That coupling's at the right front side of the 2nd (main)
> chassis crossmember.
>
> Since I have a 5 gallon "jerry can" with an attached electric fuel pump,
> I'd set that on the front bumper, and connect it with rubber tubing to the
> carburetor with a short metal adapter. However, you said you've used a
> gravity fed system in the past -- do it again, 'though I'm surprised you
> get enough fuel pressure & volume to support much engine load.
>
> Drive enough with that replacement fuel system to convince yourself that
> you've eliminated the problem; I'm confident that will prove true.
>
> If it IS a fuel problem, get those tanks down again if possible to be sure
> all the lines are properly attached, routed, and undamaged. REMOVE the
> "socks" from the fuel pickup tubes. I'd suggest replacing all the rubber
> lines with 3/8" steel while the tanks are down, but it's not mandatory. DO
> check whatever tubes you install for clear flow.
>
> With the tanks back in place, remove and sell to some other sucker that
> fuel selector valve -- it's nothing but a problem waiting to happen, IMHO.
> You haven't said what kind of electric fuel pump you're using, but it's
> apparently OK. I personally use nothing but Carter 4070's for low
> pressure. With large, easily accessible inline fuel filters BEFORE the two
> fuel pumps, combine their outputs with a tee into the hard line leading
> forward. While the 4070 does not require them, I install check valves at
> the inputs the tee just in case I have an emergency need to install a pump
> which requires them.
>
> With a 12VDC SPDT relay controlled by the wire originally serving the
> selector valve, supply the two electric pumps with independent 12VDC power
> through a circuit breaker and a low oil pressure switch (or other safety
> shutoff), using at least 16 gauge wire.
>
> With that fuel system, there's hardly any chance of your experiencing fuel
> starvation. And if you do, by simply switching the Tank Selector switch to
> the other tank, you'll transfer about 95% of the fuel supply system to
> different components. You'll probably never experience fuel starvation
> again, even from vapor lock.
>
> The redundancy is more than worth the slight additional cost of the 2nd
> pump vs that of the selector valve.
>
> JMHO & JWID (Just What I've Done),
>
> Ken H.
>
> On Mon, Jul 27, 2020 at 8:10 PM slc via Gmclist

>

> >> If it really is 133 K miles could this be a case of the timing chain
> > finally skipping at least 1 tooth ? There have
> >> been a few methods posted a checking timing chain slack/tension without
> > serious taking apart. Might a reasonable place to start
> >> be, is the rotor in the distributor in the right place when cylinder #1
> > is at TDC on the firing stock? Step 2, if step 1
> >> is OK, we need someone to post the easiest way to check timing chain
> > slack without serious dissasembly Ken B or Matt C, any ideas
> >> here? Everyone feel free to chime in.
> >
> >
> >
> > ok QUESTION
> > If the timing chain had skipped a tooth, wouldn't the engine run
> > terribly all the time, miss, etc?????????
> >
> > I ask this because until the power loss happens, 27 to 32 mph, the
> > engine fires up and RPMs climb just like normal, strong, smooth.
> >
> > I am thinking if the timing is messed up, it would not have that smooth
> > strong power build up, RPM climb in the beginning from low RPM up.
> >
> > ---
> >
> > OK so at a full stop, engine running, brakes on. the engine runs at good
> > idle, strong, no missing. Press the accellerator down, the engine will
> > raise the RPM normally, no missing, strong climb until it reaches that 20-
> > +, when it get to that point, the power loss happens. But if the RPMS
> > go down, the engine smooths out and I press the pedal, the engine reves up
> > to the point where the power loss occurs. then repeat the above again.
> >
> > This is more or less exactly what I experienced, more or less, after I
> > left that shop when the Tanks and hoses were changed all those years back.
> > I
> > have had her running at 75 mph since until this happened again.
> >
> > I do not believe the chain would slip BACK into normal position on the
> > gear.
> >
> > But I will try a couple things and if it gets more rediculous, will try to
> > check the timing chain too.
> >
> > thanks you all.
> > --
> > GatsbysCruise. \
> > 74GMC260 Former Glacier Model style. \
> > Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS
> > FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
> > UBUNTU VOYAGER - Berzin Auto Center
> >
> > _______________________________________________
> > 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

THANK YOU, I am considering almost exactly what you are saying...
slc
--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center
 
"""""" Did the mechanics replace the carb with q-jets? If so, are they the
correct ones for the 74 motorhome? What is the brand of the electric fuel
pump and do you have the spec of the pump (pounds of pressure and volume.)?
""""""

I dont know Sir.

At the time I was in a panic because MY carborator was destroyed by the rust from the
Mech fuel pump. That rust got by the Carb Fuel Filter.

Nobody had a carb available and I just happened to find a message on the GMC net about
a GMC numbered carb for sale that was rebuilt about a year before by a shop.

So It was rebuilt and I can only guess it was put back together properly for the GMC.

This carb was used for about a year, until the PO decided to change over to FI, and the
carb was removed in working, good condition.

It ran well as long as the fuel restriction didn't rear its ugly face.

Thank you
slc
--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center
 
-------------- GatsbysCruise wrote: "OK so at a full stop, engine running, brakes on. the engine runs at good idle, strong, no missing. Press the
accellerator down, the engine will raise the RPM normally, no missing, strong climb until it reaches that 20- +, when it get to that point, the power
loss happens. But if the RPMS go down, the engine smooths out and I press the pedal, the engine reves up to the point where the power loss occurs.
then repeat the above again."

Well, that's darn near classic fuel starvation, I'd say. But one more thought emerged from the fog. It MIGHT be bad gas. When the tanks were
"cleaned", did you or anyone double-check there was NO water or other foreign liquid in them before re-installation? A little water causes much grief,
especially with ethanol-blend gas. The ethanol is only tenuously mixed with the gasoline. If it finds water, it will part company from the gas, and
mix happily and tightly with the water, which also abhors gasoline. The two will dance about the floor of your gas tank{s} in a barely flammable blob,
occasionally being sucked into the fuel line. You can run a vehicle on alcohol (they do it in Brazil and on some race tracks), but it takes roughly
twice as much fuel as with gasoline. (ie: If your car gets 30mpg on gas, to run on alcohol you must re-jet, and get ~15mpg.) -------------

When that shop dropped the tanks, they were sent out for inspection. They came back shiney clean. I didn't look myself but I believe they did, but I
can't say.
I know how water attracts ethanol, it is one method used to remove ethanol from the gas. These comments revives my thoughts on maybe installing a
water separator in line, but I don't think that is the problem, but the way she lost power, after an hour or more driving at 65mph, anything can be
the fact.

AND I am pretty much looking at exactly what you mention, external tank, elect fuel pump to the carb. eliminating the existing fuel
storage/transport system. There just seems no other option at this point.

Thank you.
slcGatsbysCruise wrote: "OK so at a full stop, engine running, brakes on. the engine runs at good idle, strong, no missing. Press the accellerator
down, the engine will raise the RPM normally, no missing, strong climb until it reaches that 20- +, when it get to that point, the power loss happens.
But if the RPMS go down, the engine smooths out and I press the pedal, the engine reves up to the point where the power loss occurs. then repeat the
above again."

Well, that's darn near classic fuel starvation, I'd say. But one more thought emerged from the fog. It MIGHT be bad gas. When the tanks were
"cleaned", did you or anyone double-check there was NO water or other foreign liquid in them before re-installation? A little water causes much grief,
especially with ethanol-blend gas. The ethanol is only tenuously mixed with the gasoline. If it finds water, it will part company from the gas, and
mix happily and tightly with the water, which also abhors gasoline. The two will dance about the floor of your gas tank{s} in a barely flammable blob,
occasionally being sucked into the fuel line. You can run a vehicle on alcohol (they do it in Brazil and on some race tracks), but it takes roughly
twice as much fuel as with gasoline. (ie: If your car gets 30mpg on gas, to run on alcohol you must re-jet, and get ~15mpg.)
--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center
 
----------------- Exactly. The fickle finger of fate is pointing at the filter socks in the
tanks. Those were a big part of the fuel delivery problem on my coach when
I bought it. (17 years ago). ------------

Denny
the filter socks in the tanks were blown off by suggestion of someone a couple years ago.

---------------- The tank valve can be leaky even when it seems fine. Hence Chuck’s
suggestion to clamp off on of its inputs. -----------------

The Solenoid Fuel Valve was replaced with new. I was told not to trust the old OEM Sol valve.

slc

--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center
 
Have you considered that you got a batch of bad gas? When we crossed Canada
in 2012 we re entered the U.S.A. somewhere near Buffalo, NY. Because of
the higher fuel costs in Canada, we returned with not much of that
wonderful non-ethanol Canadian premium fuel in our tanks. So we found a
Sinclair station, and filled up. Good to go, I pulled onto the on ramp and
stuck my foot in it. Instead of taking off like a scalded cat, it fell flat
on its face, surging and faltering. I backed off the throttle and feather
footed my way onto a very busy highway. It continued to run like that for
the next 250 miles, until I pulled into a Chevron and topped off with 92
octane. That improved the driveability a pronounced amount. I continued
across the country, filling up at major brand fuel stops, it finally
cleared up about Wyoming. Bad gas is bad ju-ju. These coaches do not like
even a little bit of it. I only fuel with major brand gas now and only at
busy stations. Just sayin'.
Jim Hupy
Salem, Oregon

On Tue, Jul 28, 2020, 7:01 AM slc via Gmclist
wrote:

> -------------- GatsbysCruise wrote: "OK so at a full stop, engine running,
> brakes on. the engine runs at good idle, strong, no missing. Press the
> accellerator down, the engine will raise the RPM normally, no missing,
> strong climb until it reaches that 20- +, when it get to that point, the
> power
> loss happens. But if the RPMS go down, the engine smooths out and I press
> the pedal, the engine reves up to the point where the power loss occurs.
> then repeat the above again."
>
> Well, that's darn near classic fuel starvation, I'd say. But one more
> thought emerged from the fog. It MIGHT be bad gas. When the tanks were
> "cleaned", did you or anyone double-check there was NO water or other
> foreign liquid in them before re-installation? A little water causes much
> grief,
> especially with ethanol-blend gas. The ethanol is only tenuously mixed
> with the gasoline. If it finds water, it will part company from the gas, and
> mix happily and tightly with the water, which also abhors gasoline. The
> two will dance about the floor of your gas tank{s} in a barely flammable
> blob,
> occasionally being sucked into the fuel line. You can run a vehicle on
> alcohol (they do it in Brazil and on some race tracks), but it takes roughly
> twice as much fuel as with gasoline. (ie: If your car gets 30mpg on gas,
> to run on alcohol you must re-jet, and get ~15mpg.) -------------
>
>
> When that shop dropped the tanks, they were sent out for inspection. They
> came back shiney clean. I didn't look myself but I believe they did, but I
> can't say.
> I know how water attracts ethanol, it is one method used to remove ethanol
> from the gas. These comments revives my thoughts on maybe installing a
> water separator in line, but I don't think that is the problem, but the
> way she lost power, after an hour or more driving at 65mph, anything can be
> the fact.
>
> AND I am pretty much looking at exactly what you mention, external tank,
> elect fuel pump to the carb. eliminating the existing fuel
> storage/transport system. There just seems no other option at this point.
>
> Thank you.
> slcGatsbysCruise wrote: "OK so at a full stop, engine running, brakes on.
> the engine runs at good idle, strong, no missing. Press the accellerator
> down, the engine will raise the RPM normally, no missing, strong climb
> until it reaches that 20- +, when it get to that point, the power loss
> happens.
> But if the RPMS go down, the engine smooths out and I press the pedal, the
> engine reves up to the point where the power loss occurs. then repeat the
> above again."
>
> Well, that's darn near classic fuel starvation, I'd say. But one more
> thought emerged from the fog. It MIGHT be bad gas. When the tanks were
> "cleaned", did you or anyone double-check there was NO water or other
> foreign liquid in them before re-installation? A little water causes much
> grief,
> especially with ethanol-blend gas. The ethanol is only tenuously mixed
> with the gasoline. If it finds water, it will part company from the gas, and
> mix happily and tightly with the water, which also abhors gasoline. The
> two will dance about the floor of your gas tank{s} in a barely flammable
> blob,
> occasionally being sucked into the fuel line. You can run a vehicle on
> alcohol (they do it in Brazil and on some race tracks), but it takes roughly
> twice as much fuel as with gasoline. (ie: If your car gets 30mpg on gas,
> to run on alcohol you must re-jet, and get ~15mpg.)
> --
> GatsbysCruise. \
> 74GMC260 Former Glacier Model style. \
> Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS
> FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
> UBUNTU VOYAGER - Berzin Auto Center
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
When I made my comment about the timing chain it was because I though he said something happened suddenly and he had to be towed home.
I didn't see where he later tried to start the coach and it ran OK to a certain speed. I'd also check if the distributor some how
get stuck and there is none or improper timing advance both vacuum and mechanical. Easy to check with any timing light if you
can see the balancer at all Jim Hupy gave a good suggestion on checking the timing chain.
--
DAVE KING
lurker, wannabe
Toronto, Ontario, Canada
 
Not hard to test for water in fuel as they actually make a test kit.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Here you go Billy....i have one and it seems to be accurate etc.... and for the price you cant beat it
https://www.amazon.ca/dp/B07SH4MJT1/ref=dp_cerb_1

> Please post a link to the " 20$ vacuum gauge with fuel pressure option off
> of Amazon".
>
> Thanks
> bdub
>
> On Tue, Jul 28, 2020 at 4:49 AM 6cuda6--- via Gmclist <

>
> > Good point Ken as this could something as simple as the carb fuel filter
> > installed backwards....
> >
> > As i said in the begining....check your fuel pressure....20$ vacuum gauge
> > with fuel pressure option off of Amazon.....should be in everyones tool for
> > that matter.
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Before putting in all sorts of stuff, CHANGE THE FUEL FILTER around! It on=
ly works if it is installed correctly. This is a personal experience: We=
were traveling out west going to Tucson and stopped at Carlsbad Caverns fo=
r several days. While there one of our traveling companions opted to do so=
me small maintenance on his engine. When we left to continue our trip the =
coach would run great for a short time and then it would run out of power. =
We fought that for better part of a morning at the rest area just south of=
Artesia, NM. Looked at everything, change the fuel pump and several other=
things and didn=E2=80=99t look at the fuel filter as he said that it was n=
ew and he had changed the day before. After more screwing around, one guy =
said, =E2=80=9CLets Check the FUEL FILTER=E2=80=9D! Found that he had inst=
alled it backwards and it was restricting the fuel flow to the carb. You h=
ave to understand that this group of 4 were very knowledgable and we all mi=
ssed it at first. Damn, ran well for the next 4 months and home to Ohio fo=
r him and for several years after that. I have got group of pictures t=
hat shows how to correctly put the fuel filter in the carburetor. http=
://www.gmcmhphotos.com/photos/general-pictures/p58270-img-07751.html http=
://www.gmcmhphotos.com/photos/general-pictures/p58271-carb-fuel-filter.html=
http://www.gmcmhphotos.com/photos/general-pictures/p58269-fuel-system-q-=
jet.html http://www.gmcmhphotos.com/photos/general-pictures/p58268-q-jet-=
fuel-filter.html Be sure to read the captions under the pictures. =
Regards, J.R. Wright GMC Great Laker MHC GMCGL Tech Editor GM=
C Eastern States Charter Member GMCMI 78 GMC Buskirk 29.5=E2=80=99 Stre=
tch 75 GMC Avion (Under Reconstruction) Michigan > On =
Jul 28, 2020, at 11:49 AM, 6cuda6--- via Gmclist =
wrote: > > Here you go Billy....i have one and it seems to be accurate=
etc.... and for the price you cant beat it > https://www.amazon.ca/dp/B0=

08:48 >> Please post a link to the " 20$ vacuum gauge with fuel pressure=
option off >> of Amazon". >> >> Thanks >> bdub >> >> On Tue,=
Jul 28, 2020 at 4:49 AM 6cuda6--- via Gmclist < >> gmclist=
rg> wrote: >> >>> Good point Ken as this could something as simple as =
the carb fuel filter >>> installed backwards.... >>> >>> As i said i=
n the begining....check your fuel pressure....20$ vacuum gauge >>> with f=
uel pressure option off of Amazon.....should be in everyones tool for >>>=
that matter. >>> >> _______________________________________________=
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p://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org > > > =
-- > Rich Mondor, > > Brockville, ON > > 77 Hughes 2600 > =
> _______________________________________________ > GMCnet mailing lis=
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https://www.amazon.com/gp/product/B01GHD0NAK/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

> Please post a link to the " 20$ vacuum gauge with fuel pressure option off
> of Amazon".
>
> Thanks
> bdub
>
> On Tue, Jul 28, 2020 at 4:49 AM 6cuda6--- via Gmclist <

>
> > Good point Ken as this could something as simple as the carb fuel filter
> > installed backwards....
> >
> > As i said in the begining....check your fuel pressure....20$ vacuum gauge
> > with fuel pressure option off of Amazon.....should be in everyones tool for
> > that matter.
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Install a vacuum/pressure gauge on the inlet side of fuel pump.

Go take it for a test drive and when you get into it and it starts to
act up you should see the gauge go into a vacuum. If this is the case
you now know that you have a restriction from there back to the tanks somewhere.

I would bet the fuel socks are plugged, selector solenoid is stuck in between or the hoses
got crushed when they put the tanks back up.

At the end of the day the fuel system is simple. When we go about diagnosing it
we just need to follow a systematic approach.

One other thing to check for if it is not fuel related. If the distributor is a
factory HEI setup and could be the wires to the pickup coil in the distributor.

I have seen one wire break at the coil itself. When enough vacuum is applied to the
vacuum advance the connection will come apart and you have no spark. When vacuum drops
off connection is made again and it will keep on running. Easy way to check for this is
with a handheld vacuum pump. With the coach parked hook up the vacuum pump to the vacuum
advance. Start the engine and let it idle. Now pump up the vacuum pump to about
20 in of vacuum. Engine should speed up but run smooth. If it dies check the two wires
going to the ignition pickup coil on the distributor advance plate.

Good Luck,
Bob
--
Bob Broadwell
75 Eleganza II-Rebuilt performance engine, Manny trans, Manny 1-ton front end, 73 23ft with a side bath getting some updates-both living in Las Vegas
 
================== Have you considered that you got a batch of bad gas? When we crossed Canada
in 2012 we re entered the U.S.A. somewhere near Buffalo, NY. Because of
the higher fuel costs in Canada, we returned with not much of that
wonderful non-ethanol Canadian premium fuel in our tanks. So we found a
Sinclair station, and filled up. Good to go, I pulled onto the on ramp and
stuck my foot in it. Instead of taking off like a scalded cat, it fell flat
on its face, surging and faltering. I backed off the throttle and feather
footed my way onto a very busy highway. It continued to run like that for
the next 250 miles, until I pulled into a Chevron and topped off with 92
octane. That improved the driveability a pronounced amount. I continued
across the country, filling up at major brand fuel stops, it finally
cleared up about Wyoming. Bad gas is bad ju-ju. These coaches do not like
even a little bit of it. I only fuel with major brand gas now and only at
busy stations. Just sayin'.
Jim Hupy
Salem, Oregon

On Tue, Jul 28, 2020, 7:01 AM slc via Gmclist
wrote: =========================

Bad gas is always a problem. I try to burn it out if the vehicle sits. I use an additive or two to help too.

I dont see how bad gas could have caused this, even if possible.l

I was running down the highway at 65 for an hour or so,
Then like someone throttled down a valve, I lost power.
I struggled to keep the speed that she would run at, but whatever
it is, it got worse, slowly losing speed as I fought to go down the road.

That was an hour of good speed before the power loss showed up again.

I am thinking to eliminate the tanks and hoses up to the fuel sol valve and
use an external tank.

Im not throwing your thoughts out, that train of thought has always been in the
back of my mind. But I really don't believe I have ever had bad fuel cripple
me before.

I am working a plan out now, some of it is already in process of construction.
I hope to have her back to full speed before the end of Fall . Then next year try
to get the tanks dropped and hoses changed out.

slc

--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center
 
======== Install a vacuum/pressure gauge on the inlet side of fuel pump.

Go take it for a test drive and when you get into it and it starts to
act up you should see the gauge go into a vacuum. If this is the case
you now know that you have a restriction from there back to the tanks somewhere.

We know the problem is in the tanks/hoses up to the Fuel Sol Valve. The Fuel Sol valve was replace a year ago.
I ran a test run with a external tank, eliminating the tanks and hoses, she ran good. that proved the tanks/hoses in trouble.

I would bet the fuel socks are plugged, selector solenoid is stuck in between or the hoses
got crushed when they put the tanks back up.

The tank filter socks were blown off a couple years ago and I added a filter on the hose after the tanks and before the Mech Fuel pump. We have
changed the filters as method of trying to eliminate a problem, they never had anything in them

At the end of the day the fuel system is simple. When we go about diagnosing it
we just need to follow a systematic approach.

One other thing to check for if it is not fuel related. If the distributor is a
factory HEI setup and could be the wires to the pickup coil in the distributor.

I have seen one wire break at the coil itself. When enough vacuum is applied to the
vacuum advance the connection will come apart and you have no spark. When vacuum drops
off connection is made again and it will keep on running. Easy way to check for this is
with a handheld vacuum pump. With the coach parked hook up the vacuum pump to the vacuum
advance. Start the engine and let it idle. Now pump up the vacuum pump to about
20 in of vacuum. Engine should speed up but run smooth. If it dies check the two wires
going to the ignition pickup coil on the distributor advance plate.

The problem is not acting electrical at all. However, I will have it checked
.
I think the overall plan will be to put the OEM fuel tanks and hoses to the fuel solenoid out of service
and use an external fuel tank and electric fuel pump to supply the fuel to the carborator.
I know the tanks and hoses are in trouble and there is nothing I can do about it until they can be
dropped and hoses changed.

THANK YOU
=============

--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center
 
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