Is gas gauge working or not? 2008 Sightseer

[dennysbabe]

We have owned a 2008 Sightseer with only 19K miles for almost 3 years. We have two related issues: 1) Gas gauge read suddenly empty then 2) wouldn't take gas. (took over 1/2 hr to put in 20 gal.)

After our last outing in April we remember having about 1/2 tank of gas when we got home. Only gas used since then was for running generator for about 45 minutes in May and running engine long enough to put out the slides once which neither had used that much gas before. We're getting ready for another trip so started up engine to take out slide and the LOW FUEL light came on and gas gauge needle was flat on empty. Put in about 5 gallons from can to ensure we could get to Costco (gauge still read empty but LOW FUEL light went off going down the road). At Costco the pump continually shut off after 3-4 gallons like the tank was full. Tried 3 different pumps thinking that was the problem. We also wrapped a towel around the fill tube thinking it might be some type of vapor locking but it didn't help and fuel starting coming out of the neck of the tube. The 20 gallons total we put in the tank brought the gas gauge up to just below 1/2 tank. Going down the road the gas gauge needle kept rising and by the time we got home (10-15 miles later) the gauge was reading FULL.

We are bumfuzzled because it never should have read empty in the first place and now the 75 gal tank reads FULL after putting in only 20 gallons. We can watch mileage to determine how far we can go before filling up each time but don't know if we're really full now or if there's something wrong that's causing it to appear full. We don't want to run out of gas somewhere on the road.

Anyone have this happen to them?

Phyllis & Dennis

 

[Eagle5]

Hi Phyllis & Dennis,
It sounds like the fuel sender in the tank has gone bad, but it could also be a bad sender wire.
Eagle5

 

[Morich]

Agree that the sending gizmos have gone bad in some way.
But that should not change the way the gas flows down the tube to fill!

So the cynical side of me has to ask what the odds of somebody stealing gas?
Gas not running down the fill tube sounds like something major restricting flow?

Maybe worth a look in the fill neck for anything obvious as a stopper? Maybe go somewhat gently with a reasonably soft wire to probe down in the neck if you are not able to see?
Danger! Don't use something so stiff that it gets stuck on the sensor, etc. and creates a bigger problem!! Fishing blind can get hooked on things we don't want to tear up to get it out!

Maybe there is something hung up in the neck? Maybe somebody using a siphon tube to explain the sudden loss of gas showing on the gauge? Maybe this theoretical demon also just shoved the siphon tube they were using down into the tank and it is now fouling the sensor?

 

[wahoonc]

A couple of possibilities come to mind. A plugged vent, a bad sender or a bad wire.

Can you run something down the fuel neck and see how far down you hit fuel?

We had an old Ford Econoline with two tanks on it, one was bad but had a working fuel gauge, and the other would hold some fuel but the gauge didn't work. We had a piece of paper on the speedometer that we would use to estimate the mileage before you ran out. Due to forgetfulness and poor math, you would occasionally run out. We also kept a full 2-gallon gas can in the back just in case.

Life is an adventure, enjoy it!

Aaron

 

[dennysbabe]

Agree that the sending gizmos have gone bad in some way.
But that should not change the way the gas flows down the tube to fill!

So the cynical side of me has to ask what the odds of somebody stealing gas?
Gas not running down the fill tube sounds like something major restricting flow?

Maybe worth a look in the fill neck for anything obvious as a stopper? Maybe go somewhat gently with a reasonably soft wire to probe down in the neck if you are not able to see?
Danger! Don't use something so stiff that it gets stuck on the sensor, etc. and creates a bigger problem!! Fishing blind can get hooked on things we don't want to tear up to get it out!

Maybe there is something hung up in the neck? Maybe somebody using a siphon tube to explain the sudden loss of gas showing on the gauge? Maybe this theoretical demon also just shoved the siphon tube they were using down into the tank and it is now fouling the sensor?

That would explain the sudden change in the gauge reading but don't think that's the problem. The RV is parked in our back yard behind locked gates and we have a dog that barks at strangers in the yard. Also adding 20 gallons brought the reading up to full.

 

[dennysbabe]

Took to shop for another problem (A/C charge) and he said most likely the sending unit is going bad and that traveling down the road got it working again. Replacing it can be expensive so we'll definitely watch the mileage and fill up regularly before letting the fuel get low.

 

[Morich]

Sounds like a good plan! Sometimes we just have to look careful and try out a few ideas before we jump to the big expensive stuff.
Good to hear it seems less likely to have been somebody messing with things.

I've not got a good idea of why the sending unit would mess with the gas running down the spout, though?? I think of it as just a pretty simple pipe and as long as gas can get in and air get out, I would wonder how the sending unit gets involved?
But the folks on the scene have a far better chance of being right!!

We met somebody at an RV storage place who had a major, major problem. They first took almost all the gas, then to make it far worse, they had gathered up all the junk wood, grass, and dirt they could find and crammed it in the fill port!

I did not know the person and find what that cost them but it had to be terrible! At least they had seen the junk sticking out and not tried to start the engine which may have been even worse.

Best of luck in sorting the problem!

 

[CABender]

I once had a vehicle with similar fuel gauge symptoms. The problem was the wire that went from the sending unit to the gauge. It was ran between the top of the tank and the body of the vehicle. Over time the insulation wore of and intermittently shorted the connection. It wasn't a complete short so it would give various readings due to movement, humidity, etc. The difficulty fueling the tank is probably due to a blocked air vent which could have happened when the vehicle was over filled at some point.

 

[HappiHenri]

Am assuming that you have a Workhorse chassis. If so then consider the following:

19,000 miles is almost nothing for the life of your vehicle. That means that it has spent most of its life sitting around - not being driven - which can do terrible things. One of these is that it implies that the fuel in your tank has aged fairly well over time, turning gummy and useless. Not good for anything.

Secondly - The fuel pumps for many Workhorse engines tend to crap out over time. Usually they weaken by 75k miles, though being forced to try and pump old fuel and sludge does not help. Since the fuel level sender is integrated into the fuel pump, the erratic reading you are getting implies a sender which is grudged up and dirty - meaning that it cannot move easily. (up and down as it should).

If I were you I would have the fuel tank removed, emptied and thoroughly cleaned. Then, while the tank is removed, I would install a new OEM (AC Delco / Delphi ) fuel pump - not an aftermarket. That will give you a new fuel level sender as well as restore proper fuel pressure for your engine.

I am surprised that your engine actually ran, because even with better fuel those fuel pumps lose pressure over time. Were you getting any check engine lights?
On My 2005 Winnebago - at close to 80k miles - I began having problems with lost hill power and getting lots of check engine lights. Was advised to install a fuel pressure gauge by a very knowledgeable expert, which then showed me that my fuel pressure was way down. So I then installed a new fuel pump - which restored my fuel pressure and power.