Fuel filters or lack thereof and stalling.

[rustystud]

Well started cleaning the HH, so I go to remove the delivery screw and I'm getting ready to catch a flying spring and valve.
I pull the screw and the spring is just sitting there so I pull it out, there is no valve under the spring! How was this even running without the part?

Are you sure the valve is not stuck down in the bore ?

 

[Floridianson]

https://www.steelsoldiers.com/showthread.php?67703-What-did-you-do-to-your-deuce-this-week/page908
Post 9072

 

[FloridaAKM]

If the delivery valve is stuck shut, the engine won't run for sure. Without the delivery valve in there, your engine was not running. That makes one wonder did someone just remove(or lose) the delivery valve & just reassemble the HH & keep going? Army mechanics do some strange things to equipment, only to be bested by civilian equipment owners.

Well started cleaning the HH, so I go to remove the delivery screw and I'm getting ready to catch a flying spring and valve.
I pull the screw and the spring is just sitting there so I pull it out, there is no valve under the spring! How was this even running without the part?
Time for another ambac order, since I cant find the spider clips, there somewhere in my shop not worth hours of searching for a few dollar part.

 

[Floridianson]

It's in there just stuck. Allen you know better that it would not run without one and will not run if it is stuck open. He said his ran poorly so it is still pulsating enough but just gummy enough to not let it come out. As said remove it with the help of the in tank pump and a twist then clean.

 

[FloridaAKM]

The way I got my stuck delivery valve out was to remove the 12 point plug & spring carefully & spray carb cleaner in the bore & let it set a while. Then with a small set of needle nose pliers that fit up into the spring bore hole, wiggled the delivery valve until it broke loose. After removing it & cleaning it thoroughly with carb cleaner, the bore was next. After no more crud(this was not actually solids, but a film of biodiesel that sticks to fuel parts like superglue) would come out, I reassembled it & the engine ran for the first time since buying it. It worked for me & good luck with yours.

The delivery valve also has a screwdriver slot machined across the outside of the rear, but you can turn it, so I thought it should be added.

My memory is getting worse, even though James tries to keep me on track.

 

[DB556]

Let me look in the HH again, I was sure I could see the valve seat where the valve should be in there. But maybe I was wrong.
But I wont be able to get to the truck till next week to put the HH back in anyway were supposed to have thunderstorms for the next few days.
The driveway to the yard will be a swamp that will eat by VW rabbit pickup alive. It might be a 'truck' but its clearly not that way when it comes to traction or HP

Doing some back of the envolpe/napkin math the VW weights 1950lbs with 54hp = 36.1 lbs per hp, the M35 is 13100lbs with 130hp = 100.7 lbs per hp
one clearly wins the HP contest and 0-60 contest, But then one can carry other in the bed, who needs a spare tire, when you can just carry a spare truck?

 

[Floridianson]

Sorry Allen square valve body and round bore so it will spin around in the boar. If you can see the little hole near the end of the bore or right by the top where the threads start that is where the fuel goes to each port after the plunger lines up with the correct port. The valve being square and the bore being round that allows the fuel to pass buy the valve much better / faster. Square valve square bore the fuel would have a harder time passing buy. Just sitting here at my desk I just used the end of my finger nail clippers and spun it like at top.

 

[Floridianson]

Sorry forgot to add the reason I say use the in tank pump to help remove the delivery valve. If you just remove it and spray some crud cutter down the bore you could push any crud back into the plunger and it's bore. With the in tank running you have a better chance to push any crud out of the delivery valve bore not in. Yea your going to make a little mess but I feel that is better way to go.

 

[DB556]

You guys were right it was still in there, what I thought was the seat was infact the valve itself, I got that freed up and blew the whole head out with carb cleaner, and everything is spinning freely
its so clean now that it melted off all the old OD paint. And the wax off my shop floor. I cant find the extra spider, but since the old one isn't cracked and doesn't look bad I run and see.

Time to hike it all in and see if I put the HH one 180 out!

And then to trouble shoot the alternator.....

And pull the motor of my new crane to check the brushes....

And install a 12v alternator......

And a overhead console......

And a reverse camera....

and hydromax brakes.....

And disc brakes....

And weld up some ramps for my skid steer.....

And mount my welder in the bed....

And a radio....

And new seats.....

And.....

And.........

And.............

Oh deuce why do you cause my so many projects....

 

[DB556]

Well I hiked the tools in and got the HH back on right before it started flashing thunder and lighting.
I tried to turn it over, I cracked the lines at the injectors but wasn't getting any fuel, so I pulled the center plug
with the tank pump plugged in I was getting a better spray of fuel out of the HH than with just the booster pump.

I have fuel coming out of the delivery valve when I cracked it so I know fuel is getting that far, I played around with the shut, still nothing
I'm wondering if I knocked the button off right putting the HH back in, of if my booster pump isn't putting out enough psi?

 

[rustystud]

What you need to do now is figure out where is the last place you have good fuel flow. So start at the fuel tank and go up the fuel line. Check the fuel/water filter. Run the intank pump and see what comes out. Then go to the booster pump on the injection pump. Remove the fuel line and run the intank pump. See what comes out. Then go to the primary fuel filter (repeat)and then the secondary filter (repeat) . Then if you still haven't found the problem area go to the injection pump and remove the fuel line there. There is one other possibility if all those check out and that is your built-in fuel bypass in the filter housing. If it is stuck open it will not allow any pressure to build up. To check it, remove the fuel line which goes back to the fuel tank and start the intank fuel pump. There should be no fuel coming out the return line. If there is then the check valve is leaking and you will need to clean out the valve and check the valve seat and spring.

 

[Floridianson]

With everything correct in the system the in tank pump will always circulate fuel back to the tank without the engine running. Sounds like you have fuel getting to the head. Even with the over flow valve stuck open the 4 to 7 pounds the in tank pump puts out would keep just enough pressure in the head chamber for it to start. Even had a member say his secondary fuel filter pressure relief valve was stuck open some and it still ran. Not well but he said it ran. The delivery valve must remain closed and tight for the truck to even start. You said you had fuel coming out the delivery valve but were you able to remove it and clean out any crud plus get a good seat on the valve? Thanks to an old thread and a member secondary relief pressure 60/70. I don't know how I missed it as I went through both TM's. Think where normally I don't read I just look at pretty pictures here all I did was read and forgot the pretty pictures.

 

[DB556]

I got the gauges in today, so I'll grab some street elbows and other fitting and try to get time to install the gauges and see what my pressures are.

Fuel wasn't leaking out of the delivery valve I had loosened it to see if fuel was getting that far in the HH, I thoroughly cleaned the HH, I put my selection of bore and chamber brushes to work.

 

[rustystud]

If your pressure relief valve is stuck open (not partially open or sort of stuck open but stuck open) then you cannot build up any pressure. It would be physically impossible to do so. Your literally just opening a return valve to the fuel tank. This would be the last item I would check though. Only seen it happen once, due to crappy fuel. Having worked on these beasts in the Marines I've seen quite a few strange things go on with them. Usually due to silly young 18 year olds who haven't a clue as to proper operation of a truck.

 

[Floridianson]

Yea if you can keep it running check pressures to start with. Believe your problem is in the head somewhere but if you can get it at least started then there is hope. Performance comes later.

 

[davidb56]

With everything correct in the system the in tank pump will always circulate fuel back to the tank without the engine running. Sounds like you have fuel getting to the head. Even with the over flow valve stuck open the 4 to 7 pounds the in tank pump puts out would keep just enough pressure in the head chamber for it to start. Even had a member say his secondary fuel filter pressure relief valve was stuck open some and it still ran. Not well but he said it ran. The delivery valve must remain closed and tight for the truck to even start. You said you had fuel coming out the delivery valve but were you able to remove it and clean out any crud plus get a good seat on the valve? Thanks to an old thread and a member secondary relief pressure 60/70. I don't know how I missed it as I went through both TM's. Think where normally I don't read I just look at pretty pictures here all I did was read and forgot the pretty pictures.

I was under the impression the In tank fuel pump is centrifugal, not positive displacement (gear). which would mean that with the bypass valve set at 60-70psi, the pump would run but cavatate unless the bypass was open or the engine was running. Is there another route for the fuel to flow back to the tank from the in tank pump after the HH pump, that I cannot see in the diagram?

 

[rustystud]

I was under the impression the In tank fuel pump is centrifugal, not positive displacement (gear). which would mean that with the bypass valve set at 60-70psi, the pump would run but cavatate unless the bypass was open or the engine was running. Is there another route for the fuel to flow back to the tank from the in tank pump after the HH pump, that I cannot see in the diagram?

The in-tank pump can only reach between 10 and 12 PSI of pressure. The injection pumps "booster pump" supplies the main pressure in the deuce system. That is why you can actually get a deuce to run with a bad in-tank pump, as long as the fuel system has no leaks and sucks air. The "booster pump" is a gear to gear pump.
There is only one return line to the fuel tank and that is at the bypass on the fuel filter assembly. Returning fuel from the Hydraulic Head, and the injectors meets up here. Then along with any fuel bypassed it heads back to the fuel tank.

 

[Floridianson]

I was under the impression the In tank fuel pump is centrifugal, not positive displacement (gear). which would mean that with the bypass valve set at 60-70psi, the pump would run but cavatate unless the bypass was open or the engine was running. Is there another route for the fuel to flow back to the tank from the in tank pump after the HH pump, that I cannot see in the diagram?

If I understand your question how can the in tank fuel pump be returning fuel to the tank with the motor off. If it was not for the very small hole in the over flow valve it would not if your FDC was bypassed. Here is a picture of my return line with just the in tank running over pressure valve closed / not leaking. If it was not for that hole then it would be hard to remove all the air from any lines or the head to get a quick start. The system was designed that way so if you ran out of fuel just add some and let the in tank pump do it's thing and circulate for a short while. If everything else is correct with the engine it will start and run. Now is you question how does the in tank pump push fuel at a low pressure of 4 to 7 pounds with the stock in tank pump past the booster pump gears?
I don't know but it does. We prove that every time we put a low pressure gage on the bleed screw between the fuel filters or just crack the bleed and we get that low pressure fuel coming out.
Close off the bleed and wait a short while and we get the in tank pumping fuel back to the tank.
If you don't believe me just remove your fuel return line from the tank and turn on the in tank pump with motor off and wait a couple of seconds and the fuel will start to flow.

 

[davidb56]

@ Rusty......thats what I thought my diagram showed. there is no "constant circulation" back to the tank without the booster pump on the injection pump running and over coming the bypass valve. If the engine is not running/started, and the power is on, the In tank pump is supplying up to 12 psi to the IP, but nothing is circulating back to the tank. the line is just charged. If you had flow back to the tank with the power/ignition switch on, and the engine was not running, the bypass valve would be stuck open, or a broken spring in it.

 

[davidb56]

If I understand your question how can the in tank fuel pump be returning fuel to the tank with the motor off. If it was not for the very small hole in the over flow valve it would not if your FDC was bypassed. Here is a picture of my return line with just the in tank running. If it was not for that hole then it would be hard to remove all the air from any lines or the head to get a quick start. The system was designed that way so if you ran out of fuel just add some and let the in tank pump do it's thing and circulate for a short while. If everything else is correct with the engine it will start and run. Now is you question how does the in tank pump push fuel at a low pressure of 4 to 7 pounds with the stock in tank pump past the booster pump gears?
I don't know but it does. We prove that every time we put a low pressure gage on the bleed screw between the fuel filters or just crack the bleed and we get that low pressure fuel coming out.
Close off the bleed and wait a short while and we get the in tank pumping fuel back to the tank.

this helps with trouble shooting for me.