Something really strange has happened to my daughter's 34' Allegro Bay motor home that she recently bought, and I am totally stumped on what the problem could possibly be!

About a month ago I drove it home from Murphreesboro to the Huntsville area after filling it up first. The 100 mile trip home was uneventful. Since then it has been sitting in my driveway while she has been updating/renovating the interior to her liking. Since we don't have a suitable 110V outlet with sufficient amperage to run shore power for lighting, air-conditioners, etc, we have relied on running the generator for A/C power while working on it. The generator does run off of the main fuel tank, so when it shut down the other day and wouldn't restart, we assumed that the gas tank was now empty.

Today I tried to put gas in it from my 5 gallon gas jug, and it just flowed all over the ground like the tank was full! I went and bought a manual transfer pump so that I could push the filler hose further into the fill pipe, and that did no good either. In fact, when I removed the gas cap, the gas just started flowing out rather rapidly! I tried sticking a carbon fiber arrow shaft down in the filler to see if I could feel any foreign objects, but it felt like I hit the curve in the filler pipe and nothing else was found.

It's gonna be pricey to have it towed to a mechanic, so I'm hoping to figure this one out myself first.

Any ideas? Has anyone ever seen or heard of this before???

All help will be greatly appreciated!

I own a Foretravel with a M11 Diesel engine. The fuel for the generator(10000 watt Kubota powered diesel). comes from the fuel tank, approx. 180gal.
The fuel pick-up for the generator is at the 1/4 tank level. This is so you can't run out of fuel to run the RV engine.You must have more than a 1/4 tank of fuel to run the generator.
Gas not reaching your gas tank when filling is strange unless your not getting the nozzle in all the way.
I would try contacting a MOBILE DIESEL mechanic to come out and check your problem before I would have the RV towed someplace.
Lots of damage can be done if the RV is towed improperly. The rear axles or the driveshaft need to be removed before towing and the nuts and pieces removed need to be retained. Sometimes the axles need to be marked for proper re-install so the drive-line remains in balance.
Usually best to remove axles.

I would guess that you probably get about 6MPG so a 100 mile trip should have eaten up gas so it should not be running out the top of the tank.

Get ready to start wearing out your back pants pocket digging that wallet out.

A 34' Allegro is probably a gasoline motor. Is it new with a warranty?

Otherwise, what does the gas gauge say? I had that happen with one of my jetskis. I went to fill it at a gas station and gas immediately spilled out. I assumed my boys had filled it after we used it the last time so I left. I got to the boat ramp and it had a quarter tank. It's done it again since, but I know not why.

quote:

Originally posted by armored:
<<snip>>
Get ready to start wearing out your back pants pocket digging that wallet out.

Oh, I'm not paying for anything on it!!! This is my daughter's, and it was firmly understood that she would foot all bills on it before she ever bought it!

Oh, and it's a gas burner; I would have preferred diesel, but it is what it is...

quote:

Originally posted by trapper189:
A 34' Allegro is probably a gasoline motor. Is it new with a warranty?

Otherwise, what does the gas gauge say? I had that happen with one of my jetskis. I went to fill it at a gas station and gas immediately spilled out. I assumed my boys had filled it after we used it the last time so I left. I got to the boat ramp and it had a quarter tank. It's done it again since, but I know not why.

It is a gas burner. No warranty as it's an older model. Gas gauge doesn't work and we knew that before she bought it. A log is kept of fillups and mileage driven, and based upon an average 6mpg, we know when it gets below half a tank and will fill up right away.

We didn't expect for the generator to be used so much since it was parked before filling up again, but now I'm not convinced that it even got full the first time!

UPDATE And now for an interesting update... I decided to go back out and start it and the generator up to see if they would continue running, and they did. While it was running I tried putting in more gas and it went right in, though there was this big "thump" as I was pouring it in, like the top of the tank was expanding. (It also makes the same thump when you start it and it runs for a few minutes, indicating the top of the tank is likely flexing inward due to a vacuum building up.)

I took the empty gas jug to the station and filled it up, hoping to come back and empty it into the tank again. I started hearing pressure hissing out as soon as I started loosening the gas cap. WARNING FLAG went up in my head! I only managed about half of the 5 gallons before it started trying to backflow again, just not as bad as last time. Dammit...

I am now 100% convinced there is a vent line issue that needs to be resolved ASAP! The previous owner had a new fuel level sending unit installed but it didn't fix the gas gauge. Hopefully I can figure that problem out very soon, even if I have to add an aftermarket gas gauge up under the dash or something...

This message has been edited. Last edited by: bronicabill,

Sounds like the fuel tank is not venting.
Being a motor home they tend to sit and can get bugs and other stuff plugging them up.

Yes. It is likely a vent problem. Neighbor had the same thing.

quote:

Originally posted by powermad:
Sounds like the fuel tank is not venting.
Being a motor home they tend to sit and can get bugs and other stuff plugging them up.

quote:

Originally posted by ArtieS:
Yes. It is likely a vent problem. Neighbor had the same thing.

Agreed. As posted in my update above, I am 100% convinced that something is blocking the vent line. Just gotta wait a day or so for all of the gasoline that spilled on the dead leaves below it has time to thoroughly evaporate before I lay down under it to trace the vent line!

quote:

Originally posted by powermad:
Sounds like the fuel tank is not venting.
Being a motor home they tend to sit and can get bugs and other stuff plugging them up.

We had a spider nest block ours enough that it did the same thing. It was impossible to get more than a 1/10 of a gallon in at a time.

Once the nest was cleaned out, poof, instant success.

quote:

Originally posted by Oregon:
<<snip>>
We had a spider nest block ours enough that it did the same thing. It was impossible to get more than a 1/10 of a gallon in at a time.

Once the nest was cleaned out, poof, instant success.

How did you manage to get it cleaned out???

quote:

34' Allegro Bay motor home

Allegro is part of Tiffin Motorhomes, right there in Alabama... I would call or email the customer service line, ask about the problem, which is probably a blocked vent line or tube.

Tiffin Motor Homes
Red Bay AL
256 356 8661

customersupport@tiffinmotorhomes.com

Also this RV forum has a specific Tiffin section

https://www.irv2.com/forums/f106/

quote:

Originally posted by HRK:

quote:

34' Allegro Bay motor home

Allegro is part of Tiffin Motorhomes, right there in Alabama... I would call or email the customer service line, ask about the problem, which is probably a blocked vent line or tube.

Tiffin Motor Homes
Red Bay AL
256 356 8661

customersupport@tiffinmotorhomes.com

Also this RV forum has a specific Tiffin section

https://www.irv2.com/forums/f106/

Thanks for that info; very useful!!!

Bill, wishing you luck. I used to have close ties to the family and they used to stay at my RV Resortin Arizona, but they sold to (shudder) Thor.

Thanks to EVERYONE for their input on this matter! I will report back with an update when I can get one.

Cheers!

Great knowledge base on RVforum.net. Register and ask away. You might even try a quick search first if it allows you. But nice people for the most part.

quote:

Originally posted by Krazeehorse:
Great knowledge base on RVforum.net. Register and ask away. You might even try a quick search first if it allows you. But nice people for the most part.

Already signed up and browsing the Tiffin forum. Will scan other areas once I get the chance. Thanks!

Are you able to fill the gas tank from either side of the RV?
If so, I would try filling from the other side or try leaving the gas cap off the other side and then try to fill.
What year is the RV?
What engine?
Who made the chassis?

quote:

Originally posted by armored:
Are you able to fill the gas tank from either side of the RV?
If so, I would try filling from the other side or try leaving the gas cap off the other side and then try to fill.
What year is the RV?
What engine?
Who made the chassis?

It fills from one side only, otherwise that would be the first thing I checked once I realized it was a venting problem, but it's an awesome suggestion!

* 1995
* Ford 460
* I guess it's a Ford chassis, but not 100% sure, and not sure how to find out!

I have Edelbrock aluminum manifold and a 800 cfm Thermoquad for a 460 Ford sitting in my garage.
I installed those years ago for a Ford E350 Pathfinder Quadravan I owned.
Lots of heat under the engine cover up front.
I cured vapor lock problems with the aluminum manifold and the plastic in the Thermoquad.
In 95 you probably have a form of fuel injection on that engine.
Exhaust manifolds crack on both the 454 Chevy and 460 Ford engines because of the heat.
I also installed headers as part of a Banks system I had installed on a Winnebago Elandan I once owned. It suffered from the same fate as the Van did from high under hood temps. Tubular headers helped solve the exhaust manifold problems in both cases.

Big performance and mileage increase from the Banks installation.