Gas mileage--

[robert shimanek]

Thought I would add gas mileage experience.

Had my tank selector switch on "Fuel Aux". This was selected after about
10 miles more on the odometer when the low fuel light came on. Calulating
the distance I would have to go to get home with aux tank I made the
decision not to fill and I should have enough fuel to go the distance.

Without realizing I had a 15 knot head wind. The wind was not gusting so I
didn't sense it at that time.

Guess what-- 8 miles from home the RV quit. I looked at my fuel gauge it
it read about 1/8 of a tank. OK I said, if my generator starts and keeps
running I should have fuel to run the engine. My main tank was showing empty.

Removed the fuel line from the carb and cranked the engine. No fuel came
out of the line. So I said the fuel pump was bad. Called my next door
neighbor and gave him the engine make and model. He brought one out while
I was removing the pump on the highway. Of coarse it was not the
correct pump so I went back with my pump to the parts store to get the
correct one.

Installed the pump and cranked the engine. Still no fuel out of the line,
however my generator was still operating. (about 2 hours had elapsed) So
I got a 3 gal container went to the nearest gas station. Got the gas and
poured it in the tank. Guess what? You guessed it. The engine started.
(now I have a spare fuel pump)

I can't remember at that if I switched back to the main tank after the
engine quit and tried to start it or not

Now on my RV checklist I make sure that the fuel selector switch is not in
the AUX position when first starting out and when the low fuel comes on I
head for the nearest gas station.

Just my $.05 worth.

Bob

 

[dick kennedy]

Bob,

This wierd reserve setup was one of the big surprises when I got the GMC and
I wasn't clear on it's setup even after reading the manual. If you've been
following my other posts the tanks are one of the few remaining things that
I haven't had to dissect yet but at the current rate I expect at least one
of them to fall off sometime soon.

>From what I think I know of the operation the two tanks are connected by a
tube somewhere just below the middle. This keeps them at the same level
until the fuel level drops below the tube. This then leaves two pools which
must be specifically selected by the selector valve. It doesn't really make
any difference which is main or reserve you must first run one dry then
switch to the other. This then leaves the generator intake. The simplest
way to connect it would be to connect the generator with a T off which ever
line is designated as 'main'. This then would leave only the aux tank when
the generator ran out of fuel. The more complicated scheme would be for the
generator to have it's own pickup in the main tank somewhat above the main
pickup. This would leave fuel in both tanks when the generator runs out.

I think I've got it close to right but I'd still like to see someone jump in
and explain the details!! I think you had fuel available in your other tank
but I don't know for sure.

Let's hear from the experts1

Dick

>Thought I would add gas mileage experience.
>
>Had my tank selector switch on "Fuel Aux". This was selected after about
>10 miles more on the odometer when the low fuel light came on. Calulating
>the distance I would have to go to get home with aux tank I made the
>decision not to fill and I should have enough fuel to go the distance.
>
>Without realizing I had a 15 knot head wind. The wind was not gusting so I
>didn't sense it at that time.
>
>Guess what-- 8 miles from home the RV quit. I looked at my fuel gauge it
>it read about 1/8 of a tank. OK I said, if my generator starts and keeps
>running I should have fuel to run the engine. My main tank was showing empty.
>
>Removed the fuel line from the carb and cranked the engine. No fuel came
>out of the line. So I said the fuel pump was bad. Called my next door
>neighbor and gave him the engine make and model. He brought one out while
>I was removing the pump on the highway. Of coarse it was not the
>correct pump so I went back with my pump to the parts store to get the
>correct one.
>
>Installed the pump and cranked the engine. Still no fuel out of the line,
>however my generator was still operating. (about 2 hours had elapsed) So
>I got a 3 gal container went to the nearest gas station. Got the gas and
>poured it in the tank. Guess what? You guessed it. The engine started.
>(now I have a spare fuel pump)
>
>I can't remember at that if I switched back to the main tank after the
>engine quit and tried to start it or not
>
>Now on my RV checklist I make sure that the fuel selector switch is not in
>the AUX position when first starting out and when the low fuel comes on I
>head for the nearest gas station.
>
>Just my $.05 worth.
>
>Bob
>
>
>

 

[samuel pickens]

Dick, My understanding of the gen take off is: the fuel supply for the gen
is from the aux tank and is tapped in above the bottom so that when its out
of fuel there should be around 5 gal of gas remaining. I believe all your
understanding is correct but this may add to the gen supply. If you're
remote and can't afford to run out of gas esle you'd be stranded - the gen
runs out of fuel and you should have enough left to get 30 to 50 miles. I
believe that's the intent - remote hunters etc.
- -----Original Message-----
From: Dick Kennedy
To: gmcmotorhome
Date: Wednesday, August 19, 1998 8:55 PM
Subject: Re: GMC: Gas mileage--

>Bob,
>
>This wierd reserve setup was one of the big surprises when I got the GMC
and
>I wasn't clear on it's setup even after reading the manual. If you've been
>following my other posts the tanks are one of the few remaining things that
>I haven't had to dissect yet but at the current rate I expect at least one
>of them to fall off sometime soon.
>
>From what I think I know of the operation the two tanks are connected by a
>tube somewhere just below the middle. This keeps them at the same level
>until the fuel level drops below the tube. This then leaves two pools
which
>must be specifically selected by the selector valve. It doesn't really make
>any difference which is main or reserve you must first run one dry then
>switch to the other. This then leaves the generator intake. The simplest
>way to connect it would be to connect the generator with a T off which ever
>line is designated as 'main'. This then would leave only the aux tank when
>the generator ran out of fuel. The more complicated scheme would be for
the
>generator to have it's own pickup in the main tank somewhat above the main
>pickup. This would leave fuel in both tanks when the generator runs out.
>
>I think I've got it close to right but I'd still like to see someone jump
in
>and explain the details!! I think you had fuel available in your other tank
>but I don't know for sure.
>
>Let's hear from the experts1
>
>Dick
>

>>Thought I would add gas mileage experience.
>>
>>Had my tank selector switch on "Fuel Aux". This was selected after about
>>10 miles more on the odometer when the low fuel light came on. Calulating
>>the distance I would have to go to get home with aux tank I made the
>>decision not to fill and I should have enough fuel to go the distance.
>>
>>Without realizing I had a 15 knot head wind. The wind was not gusting so
I
>>didn't sense it at that time.
>>
>>Guess what-- 8 miles from home the RV quit. I looked at my fuel gauge it
>>it read about 1/8 of a tank. OK I said, if my generator starts and keeps
>>running I should have fuel to run the engine. My main tank was showing
empty.
>>
>>Removed the fuel line from the carb and cranked the engine. No fuel came
>>out of the line. So I said the fuel pump was bad. Called my next door
>>neighbor and gave him the engine make and model. He brought one out
while
>>I was removing the pump on the highway. Of coarse it was not the
>>correct pump so I went back with my pump to the parts store to get the
>>correct one.
>>
>>Installed the pump and cranked the engine. Still no fuel out of the line,
>>however my generator was still operating. (about 2 hours had elapsed) So
>>I got a 3 gal container went to the nearest gas station. Got the gas and
>>poured it in the tank. Guess what? You guessed it. The engine started.
>>(now I have a spare fuel pump)
>>
>>I can't remember at that if I switched back to the main tank after the
>>engine quit and tried to start it or not
>>
>>Now on my RV checklist I make sure that the fuel selector switch is not in
>>the AUX position when first starting out and when the low fuel comes on I
>>head for the nearest gas station.
>>
>>Just my $.05 worth.
>>
>>Bob
>>
>>
>>
>

 

[dick kennedy]

Sam,

Thanks for the good info. I always like to understand the details of how
things work. It may save me some grief some day.

I've had a couple of experiences along this line. Once while climbing a long
grade the main tank ran out then the aux wouldn't pick it up. I believe
this was due to a marginal fuel pump. The other time I was low on fuel and
parked in a parking lot nose down. The generator soon died. Then I turned
the vehicle so it was nose up and the generator started again. This sanity
check matches your description.

Dick

>Dick, My understanding of the gen take off is: the fuel supply for the gen
>is from the aux tank and is tapped in above the bottom so that when its out
>of fuel there should be around 5 gal of gas remaining. I believe all your
>understanding is correct but this may add to the gen supply. If you're
>remote and can't afford to run out of gas esle you'd be stranded - the gen
>runs out of fuel and you should have enough left to get 30 to 50 miles. I
>believe that's the intent - remote hunters etc.
>-----Original Message-----
>From: Dick Kennedy
>To: gmcmotorhome
>Date: Wednesday, August 19, 1998 8:55 PM
>Subject: Re: GMC: Gas mileage--
>
>
>>Bob,
>>
>>This wierd reserve setup was one of the big surprises when I got the GMC
>and
>>I wasn't clear on it's setup even after reading the manual. If you've been
>>following my other posts the tanks are one of the few remaining things that
>>I haven't had to dissect yet but at the current rate I expect at least one
>>of them to fall off sometime soon.
>>
>>>From what I think I know of the operation the two tanks are connected by a
>>tube somewhere just below the middle. This keeps them at the same level
>>until the fuel level drops below the tube. This then leaves two pools
>which
>>must be specifically selected by the selector valve. It doesn't really make
>>any difference which is main or reserve you must first run one dry then
>>switch to the other. This then leaves the generator intake. The simplest
>>way to connect it would be to connect the generator with a T off which ever
>>line is designated as 'main'. This then would leave only the aux tank when
>>the generator ran out of fuel. The more complicated scheme would be for
>the
>>generator to have it's own pickup in the main tank somewhat above the main
>>pickup. This would leave fuel in both tanks when the generator runs out.
>>
>>I think I've got it close to right but I'd still like to see someone jump
>in
>>and explain the details!! I think you had fuel available in your other tank
>>but I don't know for sure.
>>
>>Let's hear from the experts1
>>
>>Dick
>>

>>>Thought I would add gas mileage experience.
>>>
>>>Had my tank selector switch on "Fuel Aux". This was selected after about
>>>10 miles more on the odometer when the low fuel light came on. Calulating
>>>the distance I would have to go to get home with aux tank I made the
>>>decision not to fill and I should have enough fuel to go the distance.
>>>
>>>Without realizing I had a 15 knot head wind. The wind was not gusting so
>I
>>>didn't sense it at that time.
>>>
>>>Guess what-- 8 miles from home the RV quit. I looked at my fuel gauge it
>>>it read about 1/8 of a tank. OK I said, if my generator starts and keeps
>>>running I should have fuel to run the engine. My main tank was showing
>empty.
>>>
>>>Removed the fuel line from the carb and cranked the engine. No fuel came
>>>out of the line. So I said the fuel pump was bad. Called my next door
>>>neighbor and gave him the engine make and model. He brought one out
>while
>>>I was removing the pump on the highway. Of coarse it was not the
>>>correct pump so I went back with my pump to the parts store to get the
>>>correct one.
>>>
>>>Installed the pump and cranked the engine. Still no fuel out of the line,
>>>however my generator was still operating. (about 2 hours had elapsed) So
>>>I got a 3 gal container went to the nearest gas station. Got the gas and
>>>poured it in the tank. Guess what? You guessed it. The engine started.
>>>(now I have a spare fuel pump)
>>>
>>>I can't remember at that if I switched back to the main tank after the
>>>engine quit and tried to start it or not
>>>
>>>Now on my RV checklist I make sure that the fuel selector switch is not in
>>>the AUX position when first starting out and when the low fuel comes on I
>>>head for the nearest gas station.
>>>
>>>Just my $.05 worth.
>>>
>>>Bob
>>>
>>>
>>>
>>
>
>
>