fuel line schematics on 1985 P30 chassis

[waynederful]

Hello,


I have a 1985 Winnebago Elandan model WCP31RT that has had the fuel lines tampered with.  I believe there should be a fuel regulator up on the frame on the passenger side and in front of the propane tank but one line has been plugged and I think it is off of the auxillary tank.  Also there are two canisters that fuel lines go into and out of -  are there any drawings out there showing how this is set up as lines have been removed from them and bypassed all together.


I appreciate your help!

[Rickf1985]

The regulator would normally be in the back near the rear tank if you have two tanks and an electric pump in the rear tank. I have the same vehicle but mine is a 89 with one 80 gallon tank. Where you are describing the regulator is probably in the vicinity of the side entry step? That should be a fuel filter.  If the canisters up front are in the front wheel well next to the radiator then they are the evaporative charcoal canisters for the emissions system.

Note, you will not have a regulator if you do not have an electric fuel pump, 85 is the year they first started putting them in and the year of the coach is usually a year newer than the chassis so you will have to check for the pump.

[waynederful]

My beast has 2 tanks, aux. is 30 gals and the main is 60.  I have taken both off and had them coated inside and repainted.  There was no fuel pump in the tank or near it just a piece with a wire for the fuel level gauge and a double spout with several spigots for fuel lines and or return lines.  Hopefully I will be able to include some pics.  It had a fuel leak before I picked it up and they told me they removed a fuel regulator and chucked it away, so I have no reference to go by.  They also plugged a couple of lines so I don't know how to put it back to original.  There are two canisters, one is bigger than the other - the bigger one is up in the wheel well area on the passenger side and the smaller is closer to the front on the same side.

[waynederful]

The pics I posted are as follows; the first is up under the frame in front of the propane tank and you can see they plugged off one of the lines and there is an electrical connection for what I assume to be a regulator of some kind.  The second is what came out of the fuel tanks, the third is the fuel gauge which needs replacing and I am struggling to find one like it, and last is the top of the small canister where they removed two lines and also removed the line from underneath and plugged it.  It sure would be nice to see a pic of how the lines are supposed to be connected, lol.


Thanks

[BrianB]

I think that first picture, with the wire, might be where the tank selector valve was. It looks like the connector that goes on the selector valve on my 86 Chieftain.

If there is no pump in the tank, then there will be no regulator. There should be a fuel filter somewhere though. On mine it is right behind the front-right wheel well.

[M & J]

Looks like the selector valve is missing. Ranger Rick had at least one.

[DaveVA78Chieftain]

Like Rick and Brian said, there is only a fuel regulator installed if a in-tank electric fuel pump is installed.
GM only installed a in-tank fuel pump from 1985 1/2 to 1989 (carburetor chassis).  GM converted to TBI in 1990 which has the regulator built into the TBI unit
The regulator is used to drop the pressure from 13lbs to 4-5lbs.
The carburetor versions had the regulator mounted to the frame rail aft of the rear wheels
Fuel filter is mounted on the frame rail half way between front and rear wheels.
Fuel pickup:
Long tube is fuel to engine.
Shorter tube is generator supply (shorter so that you always have enough fuel to drive to a gas station.
Very short tube is fuel return line from mechanical fuel pump.

Become a full member and you will have access to:
'79-'94 Chevy/GMC P-30 Chassis Service and Maintenance Manual.  Includes lots of fuel system information

1984 GM Light Truck Service Manual (includes P30) and wiring diagrams.  Includes typical dual tank selctor valve information.

[BrianB]

Fuel pickup:
Long tube is fuel to engine.
Shorter tube is generator supply (shorter so that you always have enough fuel to drive to a gas station.
Very short tube is fuel return line from mechanical fuel pump.

I'm going to disagree here a little. On my 1986 P30 chassis:

   
• Long tube is fuel to engine (3/8 line to regulator, 1/2 line to engine)
• Shorter tube is fuel return and generator supply (generator is Teed into the line right above rear axle) (1/4 line/tube)
• Very short tube is the line to the evap canister at the front (5/16 line/tube)

[waynederful]

Hi gang,


I have looked on line and still can't find a fuel selector valve for my 1984/85 Elandan.  Everything I see is saying it is not compatible on a P30 chassis with a 454 engine.  Even a picture of the right part might get me in the right direction.

[Rickf1985]

You can't be drawing fuel from two tanks at once. If one runs out, and it will because it is smaller than the other, then you will just pull air from that tank and no fuel from the other. Physics says the path of least resistance and it is easier to lift air than gasoline. You have to have a tank selector valve and a switch for it inside somewhere.

[DaveVA78Chieftain]

I believe the original selector valve (single wire; 6 port) is no longer available.   You will either have to convert to one of the newer versions or use two 3 port valves (1 for gas, 1 for return)