Community Forums

funmoneypit · 08-23-2022, 01:47 PM

Hi all,

We have a 2004 W-22. I just noticed when it was idling in our driveway, I hear a hissing sound coming from the back of the unit. I climbed under it and it seems to be right by the gas tank. Almost sounds like a compressed air leak.

Any ideas what this might be? Fuel pump? There is about 3/8th of a tank of gas.

I did a search but didn't find anything.

TIA

TandW · 08-23-2022, 01:52 PM

The sound of gasoline returning to the tank?

Flyer15015 · 08-23-2022, 02:04 PM

Where is your gas cap ?

edgray · 08-23-2022, 02:12 PM

Quote:

Originally Posted by funmoneypit

Hi all,

We have a 2004 W-22. I just noticed when it was idling in our driveway, I hear a hissing sound coming from the back of the unit. I climbed under it and it seems to be right by the gas tank. Almost sounds like a compressed air leak.

Any ideas what this might be? Fuel pump? There is about 3/8th of a tank of gas.

I did a search but didn't find anything.

TIA

Unless a previous owner added some type of airbags to the suspension OR there is an air-operated TOAD breaking system added to the coach, I have no clue what it could be. Have you found a compressor or tank to hold air pressure?

EdInArk · 08-23-2022, 02:28 PM

Does the hissing stop if you remove the gas cap?

funmoneypit · 08-23-2022, 03:44 PM

Quote:

Originally Posted by TandW

The sound of gasoline returning to the tank?

Maybe. It really sounds like air though.

Quote:

Originally Posted by Flyer15015

Where is your gas cap ?

Drivers side just behind the rear tires.

Quote:

Originally Posted by edgray

Unless a previous owner added some type of airbags to the suspension OR there is an air-operated TOAD breaking system added to the coach, I have no clue what it could be. Have you found a compressor or tank to hold air pressure?

I haven't seen anything that would be air operated nor a compressor/tank.

Quote:

Originally Posted by EdInArk

Does the hissing stop if you remove the gas cap?

No it didn't. First thing I tried.

Thanks for the replies everyone. I am going to crawl around under it some more. The coach is new to us so I could have missed something.

EdInArk · 08-23-2022, 03:59 PM

Quote:

Originally Posted by funmoneypit

No it didn't. First thing I tried.

What builds up pressure while it's running?

Exhaust maybe? Could it be a cat converter somewhat plugged and a slight leak before it?

SteveJ. · 08-23-2022, 04:00 PM

When it is hissing remove the gas cap and get your ear near it to see if it gets louder, an indication of the fuel pump possibly going out

funmoneypit · 08-23-2022, 04:21 PM

It's definitely the fuel pump. I had my wife turn the key on but not start it. It ran for a couple seconds and then shut off. Then when you start it, it runs continuously. I guess after listening to it more, it's more of a vibration than hissing but still kind of sounds like air escaping.

Anyone change their fuel pump? Of course I just filled the tank so over 70 gallons of fuel.

donr103 · 08-23-2022, 10:25 PM

More and more members post.. that with that age.. at least carrying a spare fuel pump with you always.. any shop can change.. if you can get into one.. but it could take a while to get one.. when tank is low.. they do sound louder .. and many recommend that never run less then 1/4 tank.. because f/p uses fuel to stay cool.. there is many vid on you tube how to change f/p many different ways.. hardest part.. is getting the big old fill hoses to disconnect after years of being on.. so while you are under.. inspect all the fill hoses and clamps.. you can get that in bulk.. and carry.. if you want to wait .. How many miles? I am guessing you are not the original owner.. just a opinion.. when they get loud.. you should really consider replacing it.. one thing almost everyone agrees on.. the less fuel the lighter and easiest to change f/p.. so yes.. then you got to get it as low as you can.. while there.. I can tell you from experience.. of buying and owner of older coach.. the generator fuel line.. transition to rubber over the tank.. and the clamps get rusty and critters love to eat on rubber fuel lines.. so have that replaced too.. shop will not do it.. unless you pay for it.. they are there.. anyway.. old generator fuel line gets rotten and fine cracks and sucks air.. also.. wrap fuel line with stainless steel wire covers.. you pick that up in performance section of a/p store.. to keep critters from eating it..
Good luck and keep us posted

dieselclacker · 08-24-2022, 03:18 PM

A new fuel pump can also be heard with the engine running, especially if you are pilaging around under the coach near the fuel tank. Hearing the fuel pump run does not necessarily indicate it’s time to replace it. If you do decide to replace it, make sure you get the exact model unit that’s installed in your coach. There are several models as well as cheap knock offs available. Go for the genuine article.

winston41 · 08-24-2022, 08:40 PM

We also have a 2004 W-22 and our fuel pump has been making that noise for 11 years since we purchased it. I've checked the pressures a couple of times over the years and all appears to be fine.
Terry

funmoneypit · 08-25-2022, 02:10 PM

Quote:

Originally Posted by dieselclacker

A new fuel pump can also be heard with the engine running, especially if you are pilaging around under the coach near the fuel tank. Hearing the fuel pump run does not necessarily indicate it’s time to replace it. If you do decide to replace it, make sure you get the exact model unit that’s installed in your coach. There are several models as well as cheap knock offs available. Go for the genuine article.

Quote:

Originally Posted by winston41

We also have a 2004 W-22 and our fuel pump has been making that noise for 11 years since we purchased it. I've checked the pressures a couple of times over the years and all appears to be fine.
Terry

This was a lot louder than just a little noise. I was standing by the rear tires and heard the "hissing" noise clearly. I then got under the coach and it was loud. I know what a regular fuel pump sounds like. This was a lot louder.

I have already pumped out the tank. While doing this the pump didn't make the noise. It sounded just like a normal pump. I have read many people say theirs was making noise just prior to going out.

I have dropped the tank and removed the pump. I have a new original coming. Not cheap but I would rather replace it when I can versus being stuck on the side of the road and then at the mercy of some repair shop.

Thanks for your replies.