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Gas gauge issues all of a sudden

T
twlldeen@gmail.com
Tue, Jul 20, 2021 2:53 AM

After my shakedown cruise last week, -I'm guessing about 250 miles or so round trip, the gas gauge showed just under 1/2 tank.

I'd filled it to the brim before I left, BTW.

I've been back about a week and put about 2 or 3 hours on the Onan so I could run the fridge and keep the house battery up. Well today I had the genny
running and after about 10 mins it coughed a bit then quit. Wouldn't start again, tried to run for a second or so then died again.
Even though the coach was level and the gas gauge still showed just under 1/2, symptom was "out of gas" in my mind. Headed over to the gas station and
put $100 bucks worth in. Up here in BC, gas is $1.66/litre which translates to $6.28/us gallon and $100 gets you 59.3 litres or just shy of 15
gallons. [yep I know it's fupped up, but what can ya do]

Anyway, was surprised to see gas gauge stay at just under 1/2. Onan fired up no problem and ran steady after the fill-up.

So ....looks like the gas gauge isn't working properly? I was, as the title says, "messing about in the dash yesterday" -however if it was down enough
to make Onan quit it certainly wasn't at half a tank. The gauge might have stuck when I got back, before I took the dash apart, because it didn't
really change from just under 1/2 all week.

The gas gauge always showed the amount of gas even when ign was off which I also found odd, the other two indicators, temp and oil pressure zero out
when the engine quits, but not the gas gauge  ...normal behaviour?

Larry

Larry - Victoria BC -

1977 Palm Beach 40,000 miles, PO said everything working but forgot the word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses

After my shakedown cruise last week, -I'm guessing about 250 miles or so round trip, the gas gauge showed just under 1/2 tank. I'd filled it to the brim before I left, BTW. I've been back about a week and put about 2 or 3 hours on the Onan so I could run the fridge and keep the house battery up. Well today I had the genny running and after about 10 mins it coughed a bit then quit. Wouldn't start again, tried to run for a second or so then died again. Even though the coach was level and the gas gauge still showed just under 1/2, symptom was "out of gas" in my mind. Headed over to the gas station and put $100 bucks worth in. Up here in BC, gas is $1.66/litre which translates to $6.28/us gallon and $100 gets you 59.3 litres or just shy of 15 gallons. [yep I know it's fupped up, but what can ya do] Anyway, was surprised to see gas gauge stay at just under 1/2. Onan fired up no problem and ran steady after the fill-up. So ....looks like the gas gauge isn't working properly? I was, as the title says, "messing about in the dash yesterday" -however if it was down enough to make Onan quit it certainly wasn't at half a tank. The gauge might have stuck when I got back, before I took the dash apart, because it didn't really change from just under 1/2 all week. The gas gauge always showed the amount of gas even when ign was off which I also found odd, the other two indicators, temp and oil pressure zero out when the engine quits, but not the gas gauge ...normal behaviour? Larry -- Larry - Victoria BC - 1977 Palm Beach 40,000 miles, PO said everything working but forgot the word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system, 6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses
MC
Matt Colie
Tue, Jul 20, 2021 3:11 AM

Larry,

Delco gauges are "Air Core" design.  They stop reading when there is no power.  When there is power, the read more or less correctly, over full or
less than empty depending on the failure.

If your generator (APU) was running right and quit, the two first things I would check is can you hear the fuel pump running (click, click, click) and
if it has a solenoid fuel valve (not all do), can you hear it open.  Other than that, have you replaced all the rubber fuel line to the APU in the
last 15 years?
If the answer to that is other than yes, and the test above are positive, then that is where to start.

If given just a little love and Onan can be DC3 reliable. (You have to show it you care...)

Matt

Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

Larry, Delco gauges are "Air Core" design. They stop reading when there is no power. When there is power, the read more or less correctly, over full or less than empty depending on the failure. If your generator (APU) was running right and quit, the two first things I would check is can you hear the fuel pump running (click, click, click) and if it has a solenoid fuel valve (not all do), can you hear it open. Other than that, have you replaced all the rubber fuel line to the APU in the last 15 years? If the answer to that is other than yes, and the test above are positive, then that is where to start. If given just a little love and Onan can be DC3 reliable. (You have to show it you care...) Matt -- Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms SE Michigan - Near DTW - Twixt A2 and Detroit
CS
Carl Stouffer
Tue, Jul 20, 2021 3:46 AM

Your gas gauge is probably working just fine.  I hardly ever push my coach past 250 miles between fill-ups.  The claim of getting 8 - 10 MPG (or
better) has never happened for me.  The gauge is kind of a suggestion as to how much gas is in the tanks (similar to the coolant temp and the oil
pressure).  They are very flat tanks, so the sender doesn't have much travel.

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.  GMCSJ and GMCMI member

Your gas gauge is probably working just fine. I hardly ever push my coach past 250 miles between fill-ups. The claim of getting 8 - 10 MPG (or better) has never happened for me. The gauge is kind of a suggestion as to how much gas is in the tanks (similar to the coolant temp and the oil pressure). They are very flat tanks, so the sender doesn't have much travel. -- 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. GMCSJ and GMCMI member
T
twlldeen@gmail.com
Tue, Jul 20, 2021 6:51 AM

All the fuel lines have been changed, incl. gen so I don't think it's that. The genny usually runs just fine as it did after I gassed up. Could I have
been low on gas after a 250 mile trip and a few hours of genny use? I was pushing the 403 pretty hard up the hills. What is the range of the coach?

I appreciate the float travel is limited but shouldn't I have some movement on the gauge after putting 15 gallons in? Is it normal for the fuel gauge
to show true fuel level with ign off, key out and even after battery is disconnected?

Larry

--
Larry - Victoria BC -

1977 Palm Beach 40,000 miles, PO said everything working but forgot the word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses

All the fuel lines have been changed, incl. gen so I don't think it's that. The genny usually runs just fine as it did after I gassed up. Could I have been low on gas after a 250 mile trip and a few hours of genny use? I was pushing the 403 pretty hard up the hills. What is the range of the coach? I appreciate the float travel is limited but shouldn't I have some movement on the gauge after putting 15 gallons in? Is it normal for the fuel gauge to show true fuel level with ign off, key out and even after battery is disconnected? Larry -- Larry - Victoria BC - 1977 Palm Beach 40,000 miles, PO said everything working but forgot the word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system, 6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses
MC
Matt Colie
Tue, Jul 20, 2021 2:39 PM

boybach wrote on Tue, 20 July 2021 02:51

All the fuel lines have been changed, incl. gen so I don't think it's that. The genny usually runs just fine as it did after I gassed up. Could I
have been low on gas after a 250 mile trip and a few hours of genny use? I was pushing the 403 pretty hard up the hills. What is the range of the
coach?

I appreciate the float travel is limited but shouldn't I have some movement on the gauge after putting 15 gallons in? Is it normal for the fuel
gauge to show true fuel level with ign off, key out and even after battery is disconnected?

Larry

Larry,

Let's look at all of this.  You say you are hard pressed to make the 8~10 typically referenced.  That is very believable.  Let's (just for the
discussion) say you were running real close to 7MPG.  ~250 miles, if the tanks are the same level, then there is less than 15 gallons between them.
At 7 per tank is real close to the 6-1/4 when that is the quarter tank mark.  Please note:  I know for a fact that the quarter tank as written is just
an approximation...
If you did not carefully watch your fuel inventory, there is a very good chance that you were at less than the magic quarter tank...

And NO....
If you read the first line of what I answered to your first post of the thread, the Delco instruments of the period (and for many years after), fix
where they are when the power goes away.

There is also an interesting feature in the fuel system.  A consumer motorfuel dispenser  (aka gas pump) spits out fuel at a maximum of about 10 GPM.
If you are fueling a box stock TZE with a normal pump, between the fall from the fill neck and the pumps velocity, most if not all of the fuel added
will go to the main (rear) fuel tank.  I have done this myself and there was a demonstration of the fact at one of the internationals.

Matt

Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

boybach wrote on Tue, 20 July 2021 02:51 > All the fuel lines have been changed, incl. gen so I don't think it's that. The genny usually runs just fine as it did after I gassed up. Could I > have been low on gas after a 250 mile trip and a few hours of genny use? I was pushing the 403 pretty hard up the hills. What is the range of the > coach? > > I appreciate the float travel is limited but shouldn't I have some movement on the gauge after putting 15 gallons in? Is it normal for the fuel > gauge to show true fuel level with ign off, key out and even after battery is disconnected? > > Larry Larry, Let's look at all of this. You say you are hard pressed to make the 8~10 typically referenced. That is very believable. Let's (just for the discussion) say you were running real close to 7MPG. ~250 miles, if the tanks are the same level, then there is less than 15 gallons between them. At 7 per tank is real close to the 6-1/4 when that is the quarter tank mark. Please note: I know for a fact that the quarter tank as written is just an approximation... If you did not carefully watch your fuel inventory, there is a very good chance that you were at less than the magic quarter tank... And NO.... If you read the first line of what I answered to your first post of the thread, the Delco instruments of the period (and for many years after), fix where they are when the power goes away. There is also an interesting feature in the fuel system. A consumer motorfuel dispenser (aka gas pump) spits out fuel at a maximum of about 10 GPM. If you are fueling a box stock TZE with a normal pump, between the fall from the fill neck and the pumps velocity, most if not all of the fuel added will go to the main (rear) fuel tank. I have done this myself and there was a demonstration of the fact at one of the internationals. Matt -- Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms SE Michigan - Near DTW - Twixt A2 and Detroit
JR
John R. Lebetski
Wed, Jul 21, 2021 12:41 PM

Call it 1 GPH.  Lots of variables but that is an easy to grasp number.

John Lebetski
Woodstock, IL
77 Eleganza II

Call it 1 GPH. Lots of variables but that is an easy to grasp number. -- John Lebetski Woodstock, IL 77 Eleganza II
T
twlldeen@gmail.com
Wed, Jul 21, 2021 4:23 PM

JohnL455 wrote on Wed, 21 July 2021 05:41

Call it 1 GPH.  Lots of variables but that is an easy to grasp number.

I can see how I ran low on gas, I run the Onan about 1hr every day even at base!!

Thanks John

Larry

Larry - Victoria BC -

1977 Palm Beach 40,000 miles, PO said everything working but forgot the word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses

JohnL455 wrote on Wed, 21 July 2021 05:41 > Call it 1 GPH. Lots of variables but that is an easy to grasp number. I can see how I ran low on gas, I run the Onan about 1hr every day even at base!! Thanks John Larry -- Larry - Victoria BC - 1977 Palm Beach 40,000 miles, PO said everything working but forgot the word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system, 6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses
MC
Matt Colie
Wed, Jul 21, 2021 5:41 PM

boybach wrote on Wed, 21 July 2021 12:23

JohnL455 wrote on Wed, 21 July 2021 05:41

Call it 1 GPH.  Lots of variables but that is an easy to grasp number.

I can see how I ran low on gas, I run the Onan about 1hr every day even at base!!

Thanks John

Larry

Larry,

If that is what you want to do, fuel when you are close to arriving and run on the auxiliary tank if you are not close.  Get you fuel mileage
documented and then you will have less trouble.

Matt

--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

boybach wrote on Wed, 21 July 2021 12:23 > JohnL455 wrote on Wed, 21 July 2021 05:41 > > Call it 1 GPH. Lots of variables but that is an easy to grasp number. > > I can see how I ran low on gas, I run the Onan about 1hr every day even at base!! > > Thanks John > > Larry Larry, If that is what you want to do, fuel when you are close to arriving and run on the auxiliary tank if you are not close. Get you fuel mileage documented and then you will have less trouble. Matt -- Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms SE Michigan - Near DTW - Twixt A2 and Detroit
KH
Ken Henderson
Wed, Jul 21, 2021 10:28 PM

I don't think anyone has mentioned during this thread that the 1/4
tank=Onan Empty rule does not apply to Coachmen-fitted GMC's.  Rather than
using the added pickup point on the main tank, as does GMC, Coachmen tee's
into the engine fuel line from the Main tank -- meaning the Onan can run
the Main tank "dry".

Ken H.

On Wed, Jul 21, 2021 at 1:47 PM Matt Colie matt7323tze@gmail.com wrote:

boybach wrote on Wed, 21 July 2021 12:23

JohnL455 wrote on Wed, 21 July 2021 05:41

Call it 1 GPH.  Lots of variables but that is an easy to grasp number.

I can see how I ran low on gas, I run the Onan about 1hr every day even

at base!!

Thanks John

Larry

Larry,

If that is what you want to do, fuel when you are close to arriving and
run on the auxiliary tank if you are not close.  Get you fuel mileage
documented and then you will have less trouble.

Matt

--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit


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I don't think anyone has mentioned during this thread that the 1/4 tank=Onan Empty rule does not apply to Coachmen-fitted GMC's. Rather than using the added pickup point on the main tank, as does GMC, Coachmen tee's into the engine fuel line from the Main tank -- meaning the Onan can run the Main tank "dry". Ken H. On Wed, Jul 21, 2021 at 1:47 PM Matt Colie <matt7323tze@gmail.com> wrote: > boybach wrote on Wed, 21 July 2021 12:23 > > JohnL455 wrote on Wed, 21 July 2021 05:41 > > > Call it 1 GPH. Lots of variables but that is an easy to grasp number. > > > > I can see how I ran low on gas, I run the Onan about 1hr every day even > at base!! > > > > Thanks John > > > > Larry > > Larry, > > If that is what you want to do, fuel when you are close to arriving and > run on the auxiliary tank if you are not close. Get you fuel mileage > documented and then you will have less trouble. > > Matt > > -- > Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, > GMCES > Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum > Brakes with Applied Control Arms > SE Michigan - Near DTW - Twixt A2 and Detroit > _______________________________________________ > GMCnet mailing list > Unsubscribe or Change List Options: >