Community Forums

ToddRichmond · 12-03-2014, 01:30 PM

Hello all,

I have a 1999 Fleetwood Discovery 36T RV that won't start. Well, it did start, but as soon as the fuel in the lines ran out, it stalled, and I can't get it restarted.

I replaced the water/fuel separator thinking that might be part of the problem. That did not seem to fix anything. I was surprised to find that disconnecting the tank-side fuel hose on the separator mount did not result in any fuel flowing out from the tank, even though the tank is 3/4 full.

My question is, is there some kind of filter or other point in the fuel lines that could be causing a blockage? Shouldn't I expect fuel to drain out from the hose at the separator if it is disconnected? The temperature was warm, so I would not think diesel gelling would be the problem. Any help would be greatly appreciated.

Thanks!

-Todd

pagosajoe · 12-03-2014, 01:39 PM

Hi Todd, and welcome to IRV2! Have you checked the fuel filter? Others will chime in with suggestions...you've found a great site with great people with lots of experience.

ToddRichmond · 12-03-2014, 01:45 PM

Hi PagosaJoe (as in Pagosa Springs, CO?),

*IS* there a fuel filter between the tank and the separator? I may have missed it, but I didn't see one. Where would it be located?

Thanks!

-Todd

Phil R · 12-03-2014, 02:00 PM

Hi Todd, check for a vent line on the fuel tank. Mud daubers (wasps) have plugged mine twice. It created such vacuum that my mechanical fuel pump couldn't draw.
I'm still looking for something to put on the end of it.

Rook · 12-03-2014, 02:28 PM

You didn't tell us your engine type. If you have a CAT 3126B, 300 HP Turbo, use the manual primer pump, top front of the engine, to re-pressurize the fuel lines and injection system.....then you can start the engine. Rook

ToddRichmond · 12-03-2014, 06:50 PM

I have the 275HP Cummins ISB engine. I know I need to prime the fuel pump, but I thought that a little fuel should be flowing down from the tank due to gravity at least. Is that not correct? I'm not even getting any fuel as far as the fuel/water separator.

If there is a vacuum problem, unscrewing the fuel cap should be a temporary solution, right?

-Todd

Rook · 12-03-2014, 07:21 PM

Quote:

Originally Posted by ToddRichmond

I have the 275HP Cummins ISB engine. I know I need to prime the fuel pump, but I thought that a little fuel should be flowing down from the tank due to gravity at least. Is that not correct? I'm not even getting any fuel as far as the fuel/water separator.

If there is a vacuum problem, unscrewing the fuel cap should be a temporary solution, right?

-Todd

You are correct, unless the tank is lower than the point of the break in the line. Yes, removing the fuel cap would relieve any vacuum in the tank. You could have a "plugged" fuel line. Use compressed air to blow from the line break back toward the tank. Good luck. Rook

Bigd9 · 12-03-2014, 07:47 PM

When I had my 1997 coach on a Freightliner chassis, there was a problem with the inside of the fuel line coming apart. as the pump would suck the fuel from the tank the inside of the line would collapse and stop the flow of fuel. This problem was not visible from the outside. Its along shot, but maybe your fuel hose is bad or pinched somewhere and preventing fuel to flow?

ToddRichmond · 12-05-2014, 02:34 PM

All,

Thanks for the great ideas and suggestions. I will report back when I have tried some of them and done some more investigation.

Thanks!

-Todd

FIRE UP · 12-05-2014, 10:25 PM

Todd,
Just wondering, you don't say what, or if anything has been done lately to the coach and or engine that may have caused this. Has there been any maintenance on the engine, fuel system etc.? Has the engine been running fine prior to this incident? If you've owned it for a while, has it always ran good or, ? Or, has it been sitting for quite some time? Just trying to think of something here.
Scott

ladagobago · 12-09-2014, 06:28 AM

As for the tank having a vacuum condition - I had that experience once shortly after we purchased our used MH and did find two problems. the rollover valve on top of the tank was stuck. Also the fuel cap was not allowing replacement air. when we took the fuel cap off there was a hissing sound.

We cleaned the fuel cap with carb cleaner and used a small hand pump (found at HF) to force air into the tank via the flex tube from the top of the tank. This cured the problem which caused us the replacement of the injector pump $3800.

Now for the next problem of failing to restart. There is the lift pump on the engine which sucks fuel from the tank and between the pump and the tank is your filter/water separator. IF the filter is not tight or the drain valve is not tight you will suck air. So the only fuel you had at the start was that fuel that was left in the line past the lift pump and that was in the fine particle filter found on right side top of the engine. This filter/bowl is filled by the lift pump to feed the injector pump. There should also be a flow valve to prevent the fuel from drain back to the tank keeping the fuel lines full to the injector pump.

We once had a problem with the backflow valve draining the fine filter. so you might want to check that filter by removing the top of it by unscrewing and make sure that fuel is getting in there. to do that - with the filter top off , have someone just turn the key on momentarily, but not start the engine, to see if fuel flows into the filter bowl. While there, also check for any debris in the bottom of the bowl.

Once satisfied that fuel is flowing, continue to turn the key on several times to allow the bowl to fill nearly full. Then insert the filter. (there may be some overflow or spillage). replace the top and tighten. There should be a banjo fitting on the output of the filter. If you loosen it a little there should be flow when the key is again turn on, if there is air in the filter it will be expelled. this won't take but a few seconds so keep a wrench on the bolt and tighten.

Now that the line is full you should be able to start the engine by turning key on a few times to pressurize the lines and then turn the key all the way to run the starter..

Hope this helps. it was my experience which also a good teacher.

Skip426 · 12-09-2014, 08:39 AM

If the VP-44 injection pump has been run out of fuel, you will have to loosen at least 3 injection tubes at the side of the cylinder head to bleed the air from the system; as mentioned in these instructions; with the air out of 3 lines the engine will start on 3 cylinders and the other lines will bleed out as the engines runs.

ladagobago · 12-09-2014, 03:53 PM

Quote:

Originally Posted by Skip426

If the VP-44 injection pump has been run out of fuel, you will have to loosen at least 3 injection tubes at the side of the cylinder head to bleed the air from the system; as mentioned in these instructions; with the air out of 3 lines the engine will start on 3 cylinders and the other lines will bleed out as the engines runs.

Thanks Skip, I did not go that far when our MH lost prime. As a note, only open the injectors that are easy to reach and loosen slightly. once you get fuel injecting and bleeding at the port, tighten them back down. this will need two people with one at the keyswitch.

let us know how you make out.