Gas mileage revisited

R

ritch hwang

New member
Jul 9, 1998
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I have no guru

So how can you discern when the tanks are full? No one answered my
previous post about gas overflowing in the driver's side rear wheel well
area when filling up. And are all mileage claims suspect?

As always, best regards.

~ Ritch & Betty Hwang ~ mailto:rhwang
~ =^..^= Trinket ~ the shy Persian kitty
~ 76 GMC Birchaven ~ RVClub 00930 ICQ# 6408591
(B}>
 
Hi Rtch; Sam Pickens here, picksam Although you read
correctly, I think the writing was wrote rotten. I beleive that it leaks at
the rear of the front wheel well or just behind the left front tire. Even
then 'slow filling' are the key words.

My big question for anyone! Has anyone tried any type of auto 'level'
devices? By that I mean a probe inserted to determine where a level is or
isn't such as oil level etc. Seems I almost only raise the engine
compartment lid to check the oil; If it were auto detection that should
eliminate that. Huh? Please RSVP picksam Thanks a heap.
- -----Original Message-----
From: Ritch Hwang
To: gmcmotorhome
Date: Monday, August 17, 1998 2:41 AM
Subject: GMC: Gas mileage revisited

>I have no guru
>
>So how can you discern when the tanks are full? No one answered my
>previous post about gas overflowing in the driver's side rear wheel well
>area when filling up. And are all mileage claims suspect?
>
>As always, best regards.
>
>~ Ritch & Betty Hwang ~ mailto:rhwang
>~ =^..^= Trinket ~ the shy Persian kitty
>~ 76 GMC Birchaven ~ RVClub 00930 ICQ# 6408591
>(B}>
>
 
Ritch,

Since nobody else answered your post. If you're spilling gas when you fill
the tanks you have a leak. This is dangerous so get it fixed immediately.
I'm not knowledgable in this area so before you fill those tanks again find
someone who is.

I used to work with a guy who went fishing on weekends. He would come in on
monday talking about all the fish he caught. Each time he told the story
those fish got just a little bigger. Gas milage is a lot like that. I hear
a lot of claims which I know to be unrealistic. Last winter while going to
florida we were running entire tanks thru without leaving the interstate and
without running the generator. Under those conditions I seemed to be
getting about 10 mpg. It takes a lot of patience to fill the GMC tanks so
there is potentially several gallons variation in what constitutes a full
tank so any claims should be averaged over several tanks. Usually over a run
involving several tanks our driving is a mixed bag including a lot of
generator run time so we're never sure just where all that gas went. I keep
a book with records of all the gas used but haven't even attempted to tally
this summers performance. Even when I do I'll only have an average which
includes lots of generator run time and back roads excursions.

Dick

>I have no guru
>
>So how can you discern when the tanks are full? No one answered my
>previous post about gas overflowing in the driver's side rear wheel well
>area when filling up. And are all mileage claims suspect?
>
>As always, best regards.
>
>~ Ritch & Betty Hwang ~ mailto:rhwang
>~ =^..^= Trinket ~ the shy Persian kitty
>~ 76 GMC Birchaven ~ RVClub 00930 ICQ# 6408591
>(B}>
>
>
 
>
> I have no guru

But we have the GMCnet :-)

>
> So how can you discern when the tanks are full?

With difficulty, unfortunately :-(

The leaking fuel on the right side is probably caused by a stuck separator
valve located in the left rear wheelwell. It's allowing fuel instead of only
vapor to get to the charcoal canister which is located behind the right
front wheel.

The stuck could be caused by a real bad angle when refueling or old age. I
suspect the latter.

I finally gave up on both those gizzmo's as I couldn't find a new valve and
the repair was unsuccessfull. The repair is easy as all you can do with it
is clean it and test it by pouring liquid in it to see if it'll hold it.

It may not be the most environmentally friendly but I extended the venthose
and actually wrapped it around the valve to hold it and to prevent kinking
and tiewrapped it. Yes, that means I'm venting into air but I figure I
pollute less this way then when it pours out all over the ground.

As it is now I can hear/see it starting to spit when the venting is going
that way instead of coming back up the filler pipe thanks to all those
non-polluting fuel nozzles.

Only rarely do I miss a spit and it becomes a spurt.

FWIW, I don't top up, or at least not intentionally. I try to get it close
so that I can save a fuelstop now and then but I find that it's too big a
pain to get that last gallon in and chances are excellent it's going to spit
back at you anyhow and spill down the side of the coach.

I monitor fuel consumption over several fillups and average. I have found
over the years that in practice it's very difficult to get the same full
consistently unless you want to spend a lot of time at the pumps. Air gets
trapped, etc, etc.

Just my 2cents worth

Heinz

> No one answered my
> previous post about gas overflowing in the driver's side rear wheel well
> area when filling up. And are all mileage claims suspect?
>
> As always, best regards.
>
> ~ Ritch & Betty Hwang ~ mailto:rhwang
 
Thanks to all who responded to my gas-filling post. So now I know these
excruciatingly slow fills with no way to tell if the tanks are "topped off"
are more or less normal behavior!

As always, best regards.

~ Ritch & Betty Hwang ~ mailto:rhwang
~ =^..^= Trinket ~ the shy Persian kitty
~ 76 GMC Birchaven ~ RVClub 00930 ICQ# 6408591
(B}>
 
Ok, Ritch; I didn't speek up earlier because someone always does..
My coach leaked on the drivers side next the the rear wheels just inside the
frame area...turned out to be the vapor vent hoses where they pass together;
one from each tank over the frame below the body to the fluid/vapor
seperator located next the the driverside rear wheels/air bag. Both hoses
were rotted though and leaked when the tanks were full and liquid traveled
throught those two hoses. You should be able to change those hoses without
dropping the tanks. If the rest of the hoses look and feel good, then you
probably can put off replacing the rest for now.
While looking and replacing all those hoses, I dropped the tanks and found
all else to be in old, but perfect order. Having replaced all hoses, I get
the proper fuel nosel shut off we all are accustomed to with all our other
toys.
While filling up, I run the nosel on high until I get within 5 gals. of my
estimated fillup; 34 to 37 gallons, then slow the flow to lowest setting so
as to
not get the fuel spilling belch affect.

There was a lot said between the months of March and July about fuel tanks;
check the archives...let me know if you need more.
Good luck;

JRBIAVA
- -----Original Message-----
From: Ritch Hwang
To: gmcmotorhome
Date: Monday, August 17, 1998 12:41 AM
Subject: GMC: Gas mileage revisited

>I have no guru
>
>So how can you discern when the tanks are full? No one answered my
>previous post about gas overflowing in the driver's side rear wheel well
>area when filling up. And are all mileage claims suspect?
>
>As always, best regards.
>
>~ Ritch & Betty Hwang ~ mailto:rhwang
>~ =^..^= Trinket ~ the shy Persian kitty
>~ 76 GMC Birchaven ~ RVClub 00930 ICQ# 6408591
>(B}>
 
Thanks a bunch for your post, JRBIAVA. All input gratefully appreciated.
All the gas hose I can see/squeeze appear (including the genset) to be in
serviceable condition (including the genset). I think I just went
overboard with filling, not having any prior experience with the coach...

>Ok, Ritch; I didn't speek up earlier because someone always does..
>My coach leaked on the drivers side next the the rear wheels just inside the
>frame area...turned out to be the vapor vent hoses where they pass together;
>>> snip
 
Thanks a lot for the info, Rick. Another thing I just thought of is that I
have no real idea of how much is *really* left in the tank(s) despite what
the fuel gauge reads. I did notice that once it hits a quarter tank, fuel
useage seems to increase alarmingly (according to the gauge). I guess
I'll just be a bit more cautious on fills until I get a "feel" for it.

>Ritch,
>1 I use some rough guesstimating based upon the 50 gallon total capacity,
>how much was left, etc. ( eg: If the tanks were 1/4 fulll, should take about
>38+/- gallons to fill them.) If I ever finish fixing all the leaks, I'll go
>back to letting the nozzle do the job. (Soon...) Check the routing of your
>fill vent line (the large vent that goes back into the filler pipe just below
>the filler) and be sure it has no sags or low spots to trap fuel and prevent
>easy filling.
>>> snip
 
Your fuel system should not leak at all....even when you "over fill" as the
only path for
the over fill to go is out the fill spout. With that in mind only vapor
should excape out the vapor canister located
near the right front tire/frame area.
I could not feel the vapor hoses that ran under the body/over the frame to
the
vapor/liquid seperation valve located at the drivers side(left) rear
wheel untill I pulled the hose completely out...If I were you I would pull
those two hoses and replace them by splicing the hose where the hose travels
bewteen tank and floor. If those hoses are good and you still have a leak
in that area, then the next step is to drain the fuel tanks and drop them
down low enough to replace the remaining hoses.
Later JRBIAVA
- -----Original Message-----
From: Ritch Hwang
To: gmcmotorhome
Date: Tuesday, August 18, 1998 9:07 PM
Subject: GMC: Gas mileage revisited

>Thanks a bunch for your post, JRBIAVA. All input gratefully appreciated.
>All the gas hose I can see/squeeze appear (including the genset) to be in
>serviceable condition (including the genset). I think I just went
>overboard with filling, not having any prior experience with the coach...
>
>>Ok, Ritch; I didn't speek up earlier because someone always does..
>>My coach leaked on the drivers side next the the rear wheels just inside
the
>>frame area...turned out to be the vapor vent hoses where they pass
together;
>>>> snip
>
>As always, best regards.
>
>~ Ritch & Betty Hwang ~ mailto:rhwang
>~ =^..^= Trinket ~ the shy Persian kitty
>~ 76 GMC Birchaven ~ RVClub 00930 ICQ# 6408591
>(B}>
 
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