How to connect generator / rv fuel pump

[Mako1949]

Great site, and thank u everyone in advance. Am new to class c. Just bought A 2000 class c 23 footer Tioga with 454 in great shape. Had the fuel pump replace since, took the rv on a 3000 mile road trip and works great except my generator would only work when the rv was on. If off only work for 2 minutes then it die. Turn out the mechanic shop install the generator line to the fuel return. Not good. I can't seem to find an outlet on the tank for the generator, the fuel pump they install has 3 lines. Return, fuel to motor, third is plug nothing there. When I inspected the rv the motor was running so I don't know how it was connected. I know if I connected to the main line it's a lot of pressure for the generator pump. Took it back and installed some type of vaccum on the return line so it would not run out of fuel, same result 2 min and it dies. Is there a fuel pump that has a dedicated line for the generator. Help please, sorry for such a long question

[j-d]

On RockAuto, you can select Fuel Tank and there are a couple pictures. From them, it looks like you have to be able to see the top of the tank to see the top of the Module, where the connections are. If there's space above the tank, you might be able to see, or get a mirror in there, or maybe a camera or phone and get a photo of it. Otherwise, tank would have to come down. Some owners have cut a hole in the floor of the coach body to access the pump and made an access hatch cover to close it up. I really don't recommend that because I'm not sure I'd miss the welded steel frame under the floor and above the metal plate on the bottom. It'd suck to ruin the floor and still not be able to get to the pump module area of the tank.

[Mako1949]

Thank u all. I will try rock auto. I would love to bring the tank down to see if I can find that nipple to connected there, but I had back surgery a few years ago and am limited to what I can do, and I though about another tank but I think in the long run would b more trouble.
Is there any way to see or find out where the nipple is in the tank, maybe if I know in the area I can look to see if a can find it

[j-d]

"Fuel Pumps" are sold as "Modules" (pump, fuel gauge sender, intake filter, wiring, mounting plate to fuel tank, gaskets) or as "Pump Repair Kits" (basically pump only, maybe with the intake filter).

If you go to www.rockauto.com then Chevrolet, then 2000, then Express 3500, then 7.4L/454 engine, then Fuel/Air, you'll see Modules with fittings for "auxiliary power unit" or "fuel take off." I think one of them is what you'll need.

Suggest you read those listings carefully and gather the info to describe your specific vehicle. Some of it may be in the VIN, or door sticker, but I remember GM including what I'll call a "build label" that contained details about what went into a vehicle. Then call Rock Auto and see if you can confirm that one of their Modules is what you need, to get back to that extra fuel pickup.

[SoCalDesertRid1]

I would install a separate tank just for the generator...

[Hemi_RT]

The Generator has its' own fuel pump. The generator you have is a built in unit and not an added portable one some one stuck in I take it. If it's a built in unit then tap into the fuel line before the electric pump. A picture of what you have would help.

[Mako1949]

I have even called rv repair places and nothing as far as the fuel pump

[Mako1949]

Thank u for ur help. The mechanic says that the third connector in the fuel pump Does not goes down to anything, it just comes up out of the pump. When he install the pump he said the third one does not goes down. Any idea where the connector in the tank will be. And do they make pumps with a dedicated line for the generator, cause I been calling around and can't find it, even called the Chevy dealer for medium size truck and they don't now

[j-d]

A Class C Motorhome Prep Chassis should have an extra fitting on the gas tank. Dedicated to the generator, it should extend about 3/4 of the way down into the tank. This is so you can run the generator till it runs out of gas and still have 1/4 tank to get your motorhome to a gas station.

It can be very difficult to access that fitting to add a hose for a generator if that was not done at the factory, before the House was built onto the Chassis.

You're right about fuel injection. The line FEEDING the fuel injectors is more pressure than the generator can accept. It'll force gas through the float valve and overflow the carburetor.

Fuel injection uses a Pressure Regulator and a Return Line to the tank. From what you've said, it seems to me that the genset is being supplied by the Return Line. The Regulator limits pressure to a certain spec for the fuel injectors, and allows any excess (which there should always be) back to the tank via the return line. No problem when the road engine is running, no return flow when it's not.

Trace the lines from Tank to Engine Compartment, or Compartment back to Tank. There should be TWO for Supply and Return, plus a Third for the Generator. Now, trace the Third one.

[Hemi_RT]

I take it you are talking about an electric fuel pump. If so the generator doesn't use/need an electric fuel pump and it may harm the fuel pump on the generator. Sounds like the generator is getting fuel from this pump or the fuel line is coupled into the fuel line after the electric pump. If so just move the generator fuel line to before the electric fuel pump.

You can have a fuel nipple put on the fuel tank for the generator but finding a shop to do it may be a problem. If you tap into the MH fuel line before the fuel pump remember that you can suck the fuel tank dry; most pick ups for generators are tapped into the fuel tank in a way that when the generator runs out of fuel you will have some where between a 1/3 to 1/4 tank of fuel left so you can make it to a gas station. If the generator was factory installed the generator fuel line should be coming off the tank. You may want to check the tank and see if there is a plug on the side of the tank, this plug is where you would put a nipple in place of the plug then hook the generator fuel line to it.