mystery pump?

[jagcb750]

o.k. here goes.

I was working on Nancy Yesterday and got some stuff completed. I hooked up water to her and all went well. Then I filled up the front airbags to about 55 PSI and they are holding pretty well. There was zero pressure in them when I started. Then I went to the back and filled up the rear air bags through the schrader valve located on the bottom of the tank. The rear bags were partially filled already until the compressor above me under the Queen bed. I kept filling until the pump stopped being "Called" to pump. Everything seemed pretty good. However, there was a strange noise being emitted out of a pump looking outfit that is located between the tanks. It has electric to it and a hose going in and out of it. It was making a weird sound and if you pressed on the unit it would quiet down just a little. Anyone know what this contraption is or what it does? If I need to where can I locate one for replacement? I will try to get a picture of it and post it. It is raining here in South Eastern Kentucky right now or I would have posted one already. I have my coach documents put up right now and I was going to see if I could figure out what it is. I thought it might have something to do with the rear air bag system. Maybe a way to equalize pressure from left to right? Anyway I could guess all day, but I figure someone on here knows and wouldn't mind sharing the knowledge. Thanks in advance to all.

[richinny]

what kind of hose? could it be a fuel pump?

[jagcb750]

a rubber hose, almost the size of my little finger. I suppose it could be. I had the coach running when it was making all the noise of course and Nancy was running smooth.

[swebster]

Sounds like your fuel pump. Later (and longer) models had an electric pump installed behind the air tank (between the tags) to help get the fuel all the way up to the mechanical pump on the engine.

It' comes on with the ignition. Trace te rubber hose...I'll bet one end goes up and behind the top of the fuel tank.

[Fyrzowt]

Swebster is right - trace the hoses to their source/destination.
Three kinds of pumps come to mind at the moment. Fuel pump, air compressor(pump) and vacuum pump. The hoses will likely give you the answer.

[jagcb750]

Thanks, I will try. Seems like I did try to trace them the other day and they vanished up under the floor. I will try again and this time take a pic to post on here. I did unplug it briefly the other day and it didn't seem to effect the running of the coach. Of course it shut off and the noise went away. But I plugged it back in so as not to damage anything.

[JKWoodrow]

That is the electric fuel pump. Standard item - I bought mine at NAPA.

[jagcb750]

update: Well I took the pump off this weekend and indeed it is an electric fuel pump as stated by others above. I went to a local parts store. They suggested that I put a new generic electric fuel pump on. I decided against it for the time being. He did manage to find one that looked identical to it in a catalog that he has. Part number is: E84389. He said it is $138.34 with a discount. I looked it up by the part number he gave me on the internet later and I found one delivered to me for $122.65. Before I go this route, Is there another less expensive source for these? I am also thinking about attempting to replace the fuel lines throughout Nancy. The lines look pretty cruddy and Nancy is roughly 22 years old now. I just dread trying to fish all that gas line along the chassis to the front. And trying to figure out how to replace the tubing down into the gas tank for the fuel delivery system and the line that feeds the Onan.

[gunner]

I purchased mine at Auto-Zone considerably less expensive and the same part.

[jagcb750]

Thanks gunner. I went to Autozone's website and found the part for $98.57 including tax. I don't think I could get it much cheaper without a lot more time wasted on it so I went ahead and ordered it.