Was working on a side hill and sucked some junk into the fuel system from the bottom of the fuel tank. Had intermittent power loss when this first happened. Drained and cleaned out fuel tanks, blew out fuel lines, and installed new filters. Now the machine won’t idle. I am not lacking any power at full throttle. Disconnected the fuel line at the lift pump and ran ATF through system and bled air at injectors. After doing this and running the engine a little while, I could lower the rpms a little more without it running out of fuel. Rpms are inconsistent if I hold the throttle just above the spot where it runs out of fuel and dies. Injection pump is a Bosch “A” type with RSV governor. Any help would be appreciated.
Sounds like it's sucking air to me. Cracked rubber line? fuel filter gasket? fuel line connection? Or check the fuel return with a clear hose, or a hose into an open can of fuel to check for bubbles.
Forgot to add that I did pressurize the fuel lines from the lift pump to the fuel tanks, and they held pressure. Also replaced lift pump - waste of 90 dollars. I’ll check the fuel off the return line. The filter housing seems tight. I changed the filters several times and it still acted the same, so I don’t think it’s a filter gasket. Very little seepage in this area.
Inspect your overflow valve? How does it start? Are you maintaining fuel pressure in the pump itself. Tee in a vacuum gauge on inlet of lift pump. See if you exceed 4" when running. Check pump pressure after lift pump. 40-45 psi full throttle no less than 40 @ idle or near idle.
My guess is the overflow valve too.. its the banjo bolt on the return side.. it should have a ball & spring in it.. Just shake it & see if it rattles.. if so, that's your problem.. U can also blow it out.. Also blow out the return line back to the tank.. If all else fails, bump the idle up.. The TOP screw is for RPM's & the MIDDLE screw is for surge.. U only need 25-35 psi to make it run correctly.. u can T into the inlet on the inj. pump. I have a regular old metric banjo bolt that I drilled & tapped to accept a fitting that'll screw onto my gauge.. I replace the pumps INLET banjo bolt w/ mine & take a pressure reading.. & just because supply pump new, doesn't make it good.. U "could" loosen the inlet banjo a few turns & get someone to crank the engine.. it should squirt fuel 1/2 a block.. Good luck.
ROFLMFBO Btw, thanks for checking me on those pressures.
Lol.. really anything over 25 is a plus.. U gotta have 25 to open the overflow valve..
You said that you sucked up some junk and then you started having this problem. I once had a similar problem and it turned out being that I had a bunch of junk trapped in the fuel filter base. I hope this will help. Good luck
Thank you for the advice. I’ll try the suggestions. The machines starts after a few cranks, so long as it is throttled up. It won’t start at lower rpms. I did blow out the return line from the injection pump down. Does anyone have a schematic for the overflow valve?
Huh?? How it comes apart?? Some do & some don't.. IF it has a small 14mm nut on top of it, it comes apart but they/Bosch doesn't sell parts for it.. u have to buy an assembly.. IF your going to take it apart BE CAREFUL>> on the 14mm "nut" there are SHIMS.. on the inside/back side of it..
Did you check to make sure the fuel shutoff was pulling the fuel lever all the way open?
I did. Unhooked solenoid from lever to make sure it was open all the way. Pulled the overflow valve and cleaned today. Didn’t find any foreign material stuck in it, and it didn’t run any better. I’ll check to see if the filter housing is clogged tomorrow. Then try to rig up a pressure guage.
Checked pressure at injection pump. It was between 30 and 40 psi, between lift pump and injection pump. Should I try a new overflow valve? Or should it be running properly?
No that's perfect.. BUT was that at low idle.. U gotta take it at hi idle too.. "Mash the gas" for a few seconds. what are the RPM's at idle.?? If I remember correctly, depending on the application, it should be about 1000..??
Machine doesn’t have a tachometer. I checked at the lowest rpms the machine would stay running, then at about 3/4 throttle. After running a bunch of diesel additive through the system, I can now run at lower rpms than before. I can now keep the engine running just above what should be a normal idle, but rpms are still sporadic on the low end. It will still run out of fuel and die if I drop rpms too low. When I took the filter housing apart, I found a little bit of what looked like fine black sand, on the dirty side of the filter housing. Found the same stuff in the bottom of the fuel buckets when I drained the tanks. I am concerned some of this stuff may have got through the filters. Any thoughts? Should I just keep running additive and hope it clears up? Anything else I can check or clean out?
I think your just pizzin in the wind my friend.. The additives/injector cleaners are made to clear up organic problems.. it sounds like yours is sand..?? Are u just using an additive.. disperses water & boosts cetane.?? TRY an "INJECTOR CLEANER".. & good luck..
Ran a clear line off return to a bucket. Didn’t get any bubbles at all. To clarify on this “sand”, It resembles the dirty looking material that you find in the bottom of all new hydraulic oil buckets. No noticeable texture. I’ll run it a while and see what happens.