WMO and Surging

[gimpyrobb]

Its your thread, do with it as you please! It sounds to me like you should try to turn up your fuel a few flats. It helps them start and run better.

 

[LowTech]

I've had sometime to work on this again,
first I pulled the line to the flame heater and plugged it, at the flame heater filter & at the "T" between the injectors. That kept the return line from filling w/ air when I turned off the power. If I left it for a few hours I would still get a bubble in the return line, I figured small leak where I tried to cap off the "T" between the injectors? It does leak some fuel out . . . very little!
I then decided that I should just replace all the return lines. I found some 1/4 nylon that I can see into. Then came to a dead end when people started looking at the type of ferrule used. It seems that these are NOT like a little bead, they seem to be somewhat flat on the back side w/ a step that the male thread nut sets on.
Are these something that I can get? Can I use the standard "bead" type of ferrule? Don't tell me that I have to replace all the fittings

I have tested the in-tank pump it's 3psi at the secondaries, and I can hear it returning to the tank.

Is there some other place that I should check for air getting into the system?

Thanks for the help so far, and any future help

 

[Barrman]

Check the fuel line that runs under the radiator. If you are on the trails, maybe it got bashed, flattened, cracked, kinked or something. Otherwise, it is back to filters, filters, filters. Sounds like you have checked things over pretty good and didn't mention this.

 

[LowTech]

The fuel line under the rad is great, no probs there. I have changed the filters a few times, like I said in the first post, changed the primary twice the first day that it happened and changed the others as well. It made no change to what it's doing.
It runs great when I first start it and for the first 20, or so, miles.
Don't know why that would let air into the system if they were restricted. Is there something that I'm missing?

 

[Djfreema]

I would pull the in tank pump and make sure the screen is not getting plugged up with debris. Make sure there's nothing in the bottom of the tank to get sucked into the pump intake. One little piece of cardboard or paper could be sloshing around on the bottom of the tank then get sucked flat against the intake causing the fuel starvation. After you shut it off, the fuel slowly flows back down into the tank releasing the debris from the screen which lets it run fine again until it gets sucked up again. For air in the return lines, i would try tightening all the lines or just replace the lines and ferrules with new ones. I did this on one of my deuces and it fixed the need for excessive cranking time when starting.

 

[Wildchild467]

all the suggestions these guys have said are great and its good to check what they said too. you could put a fuel gauge on the bleeder port of the final fuel filters with a long hose so you can see it in the cab. drive it down the road and see when it cuts out if you lose pressure going to the filters. thats just another thought. it should be around 30psi at idle and 60psi around 2000-2200 i believe.

 

[offroadrunner]

Another possible restriction could be any of the rubber-fuel-lines themselves. You might have gotten some nasty chemical mixed in the WMO that caused one (or more) hose to begin to swell or delaminate (think small flakes or flaps) from the inside - thus blocking fuel-flow and/or introducing air. It's further possible that this could get worse with temperature and/or flow-rate (higher engine RPM) when in-use. The fuel-pressure-gauge (mentioned above) might help you determine this.

Good luck,

 

[Floridianson]

I don't understand how I would get air into the lines. If the fuel system is pressured from the tank pump on why would it not leak out instead of in?

Correct it would show up as a fuel leak from the tank to the ip because it is under pressure. This is what some forget. Now air could get in if the rubber hose in the tank was bad. The intank pump could push out some fuel and it would squrt out the bleed screw on top of the final fuel filters and with out a gage showing and 4 to 7 lbs you might think it is ok. Problem is when the IP fuel pump starts to kick in at higher rpm now it will suck air from the bad rubber hose in the tank.

 

[LowTech]

I would pull the in tank pump and make sure the screen is not getting plugged up with debris. Make sure there's nothing in the bottom of the tank to get sucked into the pump intake. One little piece of cardboard or paper could be sloshing around on the bottom of the tank then get sucked flat against the intake causing the fuel starvation. After you shut it off, the fuel slowly flows back down into the tank releasing the debris from the screen which lets it run fine again until it gets sucked up again. For air in the return lines, i would try tightening all the lines or just replace the lines and ferrules with new ones. I did this on one of my deuces and it fixed the need for excessive cranking time when starting.

I did think of that as well, the thing that dropped it farther down the "list of things to check" was that it would happen at all most the same amount of time from the start of driving. Not just some random amount of time.

all the suggestions these guys have said are great and its good to check what they said too. you could put a fuel gauge on the bleeder port of the final fuel filters with a long hose so you can see it in the cab. drive it down the road and see when it cuts out if you lose pressure going to the filters. thats just another thought. it should be around 30psi at idle and 60psi around 2000-2200 i believe.

I did put one on the bleeder, but not when it was running that info came after I gave the gauge back.

Correct it would show up as a fuel leak from the tank to the ip because it is under pressure. This is what some forget. Now air could get in if the rubber hose in the tank was bad. The intank pump could push out some fuel and it would squrt out the bleed screw on top of the final fuel filters and with out a gage showing and 4 to 7 lbs you might think it is ok. Problem is when the IP fuel pump starts to kick in at higher rpm now it will suck air from the bad rubber hose in the tank.

I did think about that, when I had some probs w/ my truck this winter I pulled the pump to see if it was all together and thought my hose didn't look so good (don't laugh!). This did start when she was pretty full of fuel and it didn't really change based on the level. I do know that it could be above the fuel level and will check that if it keeps happening.
Is this hosing that I can just have some hose place here in the city make, or is it Mil special? I'm thinking that as long as the ends are right and it's fuel line I should be good.

I did pull the section of return line, that has the "T" going to the flame heater, out and replaced it. I used a piece that went to the heater, cut one new end, reused the ferrule (it takes a little reaming from the back side to get it so that it fits on to the line), and ran it some.
After shutting it off the lines did NOT fill up w/ air, just a very small bubble. A few hours later it had not grown any (that was a good sign). This morning it was still the same.
So I drove it to do some tasks that needed doing, maybe 15 + miles (forgot to look) and it did not act up any.
When I got back to the "Dry Dock" and shut it down it did the one small bubble again. Seems to be a series of tiny ones coming up from the IP. I'll check those fittings and drive it some more tomorrow.

I'll still prob borrow the pressure gauge back and check when the engine is running, maybe even get one to mount on the dash. It would tell me what condition the filters were in, right?

Thanks everybody,

 

[offroadrunner]

OK - here's another "out of the box" thought: Could it be that the in-tank fuel-pump is not getting full voltage? If it's not, it could give pressure at low-flow rates, but not be able to keep up at high-flow (especially with thicker fuel - WMO) and allow the IP to suck air (from somewhere?). If either the +24 OR the ground-path is corroded, it could be "seeing" less than 24-volts and running slowly (or it's just plain worn)? Don't know if that would get worse when it gets used a while (warmed-up) or not though.

Just a thought - how hard is it to swap in-tank-pumps from your truck to hers? Might help narrow-down the possibilities - if the problem recurs.

Once again: good luck,

 

[LowTech]

OK - here's another "out of the box" thought: Could it be that the in-tank fuel-pump is not getting full voltage? If it's not, it could give pressure at low-flow rates, but not be able to keep up at high-flow (especially with thicker fuel - WMO) and allow the IP to suck air (from somewhere?). If either the +24 OR the ground-path is corroded, it could be "seeing" less than 24-volts and running slowly (or it's just plain worn)? Don't know if that would get worse when it gets used a while (warmed-up) or not though.

Just a thought - how hard is it to swap in-tank-pumps from your truck to hers? Might help narrow-down the possibilities - if the problem recurs.

Once again: good luck,

Put my pump in her tank!? Don't know where that thing has been!

The ground has been cleaned. I mounted some other ground line in the same place when I was running the wiring for the box.

I did go out for some driving today. Did about 75 miles, city streets, dirt roads, high rpms for extended time. Had no probs . . . till the fuel got low. Now I'm thinking that it may well be the hose from the in-tank pump to the fitting going out of the tank. The first time it happened (thoe it may have happened many times and was fixed by changing filters . . . and adding fuel, or fixing something else . . . and adding fuel) the fuel level was higher . . . AND it was a cold, just above freezing, morning w/ mostly WMO in the tank.
I'm guessing the oil, being cold and thick, resisted being sucked up and that caused it to suck air through some cracks in the hose.

We'll see tomorrow when I pull it out. I'm going to replace it no matter what. That will just take one more thing off the list of "things that would be great to do . . . one day".

 

[LowTech]

I pulled the pump out the other day, sounds easy doesn't it? It's held in w/ 10 phillips headed screws. 6 of those came out easy, 3 were a bit of a challenge, 1 just rounded out!
I had to turn an old screwdriver into a cold chisel, get a groove into the side of the screw head, and tap for a while to get it to finely turn loose.

Now I discover that you CAN'T lift the pump out like on a cargo-bed. the floor of the 109 is lower it stops the pump coming all the way out. So . . . disconnect all fittings from the tank and slide it out far enough to pull the pump.

What I discovered in the tank -
1) I (she) has a new pump.
There are a couple of those shims for the bottom of a pump inside the tank. So it looks like there was pump failure, by a bottom dropping, and they put in a new pump. This one has a couple of rivets holding the bottom together.

2) the hose from the pump up to the top fitting is new looking as well.
You can still read the numbers on it and it looks great. The band (one of those you can't adjust) on the top connection was loose enough that I pulled it off the fitting w/o much effort and then took it off the hose. I replaced that w/ a standard hose clamp and tightened the one on the bottom a bit more.

3) There was some blockage of the pick-up screen.
I wire brushed the screen clean, as well as wire brushing the rust off the inside of the top (where it never is under the fuel and gets condensation)

4) The pump was about a 1/2" off the bottom!
That just seemed like a really bad idea.
I moved it up so that it's closer to 1 3/4" - 2" off the bottom. Using Alt Fuels makes me want to have some space between the pick-up and the bad stuff that "might" get in there. I believe that I read somewhere that 2" is the height that it should run at and that seems right to me.

In the tank I found -
2 shims from an old pump failure,
some bits of screen from a filler tube bottom screen (seems like they would have taken it out of the tank before they punched it out/in when it clogged),
and a decent amount of grit.

I scraped the inside of the tank to loosen stuff and then rinsed it, multi times w/ gas, out the bottom drain (that's when I discovered that her jerry can had crap in it . . . and I was NOT pouring it in through the filler neck screen. Guess I was meant to rinse it many, many times).

That is all back together and just waiting for enough fuel to start checking pressures.

 

[gimpyrobb]

Sounds like you got lucky with a newer pump.

 

[offroadrunner]

...
4) The pump was about a 1/2" off the bottom!
That just seemed like a really bad idea.
I moved it up so that it's closer to 1 3/4" - 2" off the bottom. Using Alt Fuels makes me want to have some space between the pick-up and the bad stuff that "might" get in there. I believe that I read somewhere that 2" is the height that it should run at and that seems right to me.

Hey LT,

That presumes any "bad stuff" is heavier than the fuel it's mixed with. The problem I can see with raising the pickup off the bottom that much would be cavitation (sucking air) when you've still got a good bit of fuel left in the tank (especially when the truck is at a bad angle - or sloshing around when off-road); i.e.: significantly reduced range on a tank of fuel, no? Just sayin' you'll need to plan your fuel-stops better than if it's lower.

Cheers,

 

[DHennon]

I had a similar problem with loss of power when I had about 3/8 tank of fuel. I have been running diesel with 1 qt of new motor oil with each 20 gallons of diesel. I cleaned the fuel system from the bottom of the tank to the IP, and replaced all the filters. When I pulled the pump I found several slits about 1/2 way up from where the fuel line goes from the pump up to the top of the plate on the fuel tank. Those slits were at about the 3/8 tank level. I replaced that fuel pick up line and no problems since.

 

[LowTech]

Hey LT,

That presumes any "bad stuff" is heavier than the fuel it's mixed with. The problem I can see with raising the pickup off the bottom that much would be cavitation (sucking air) when you've still got a good bit of fuel left in the tank (especially when the truck is at a bad angle - or sloshing around when off-road); i.e.: significantly reduced range on a tank of fuel, no? Just sayin' you'll need to plan your fuel-stops better than if it's lower.

Cheers,

Thanks for the input, It made me do lots more reading and researching TM's. Seems like when the pump is at it's stock depth (15.1", which makes it almost on the bottom) the running out of fuel happens around < 2". I just added almost an 1 1/2" to that . . . not really what I wanted to do. I was thinking that if the bottom of the pump was under that would be fine . . . now I know that I need to have the side screens under as well.

Guess I'll pull it back out and re-locate it. I know how

 

[mikey]

Thanks for the input, It made me do lots more reading and researching TM's. Seems like when the pump is at it's stock depth (15.1", which makes it almost on the bottom) the running out of fuel happens around < 2". I just added almost an 1 1/2" to that . . . not really what I wanted to do. I was thinking that if the bottom of the pump was under that would be fine . . . now I know that I need to have the side screens under as well.

Guess I'll pull it back out and re-locate it. I know how

save yourself a bit of work and road test it thoroughly before you drop the pump... no sense in doing the work if you need to go back into the tank next week to revisit the original problem anyway...

 

[bill2444]

Hi, I just experienced some of the same surging you were experiencing. Found out it was the pump not putting out enough pressure/volume when the tank fuel level was getting low. It was fine when i filled it, but would start to surge at about 1/3 left in tank. I had a fuel pressure gauge in the dash which helped me diagnose. Other wise i would have hard a very hard time trying to figure that one out. Replaced the pump and all is well.

 

[LowTech]

So this is the latest on the fuel issues of the "She Beast",
Just ran two more tanks of WMO through her while we were crossing a few more mountain ranges and putting another 400 miles on the odometer. She has been running GREAT!
I would say that it was the hose from the in-tank pump being loose at the top fitting that gave us the problems. Now if I can get mine to run as good as hers.
I've been thinking that I should check the hose on mine as well, it's already been said that it hard starts and loses power on grades. I've been considering turning up the fuel a tad, but wanted to know that everything else was right first. Filters have been changed and are new. So today I pulled my pump and checked the condition of the hose. It to was lose at the top. Replaced the top clamp w/ a standard hose clamp, was going to replace the hose till I started talking to hose places and found that I really need to have a "Submersible Fuel Line". Not easy to find on a one day lay-over, and not cheap! I'll save that till I get back to Base Camp.
I did pull the return line and check the flow . . . not huge but there was a flow (and I do know that I have a bit of a dent in the under rad hard line).
The "little Draggin' " now seems to idle better, and in the morning I'll see if starting is any better. After that I may bump the fuel . . .

I would def suggest that checking the tightness of the hose to the top fitting be added to the list of things that one does when first going over their truck. We are 2 for 2 w/ them being lose.

Here's some pump pics,
the riveted bottom,
the top,
and bottom fittings,
the hose that pulled easily off the top fitting, on both trucks (w/ the clamp still on),
and the mod that I did by replacing the mounting screws w/ socket head machine screws. Now if they strip out I'll still be able to get a grip on them w/ vice-grips, or the like.

And a couple from the last 400.

Sounds like you got lucky with a newer pump.

Both of our trucks have the riveted base on the pumps and that's not luck, that's manifestation . . . you know . . . the same thing that manifests road side repairs