No Fuel from one of the injection pump ports

[pvogt38]

Folks,
After 6 months of wondering why my L3800 HST (with 400 hrs on it) just doesn't seem right, I discovered this morning that it has been running on two cylinders since I bought it. (rookie).
1) Engine running, I loosened the forward most port at the top of the injector pump, and engine immediately tried to die. I quickly tightened it back. Engine recovered.
2) I could not get a wrench on the middle port, it was to close to the others.
3) I cracked open the fitting on the rear-most port, and nothing happened. Engine did not stop, and no fuel came out. I then opened the fitting completely, and confirmed that no fuel was flowing. (engine running).
Is there anyone out there that can advise me what to do? I will fix this myself if it is not too difficult.
Thanks So Much,
Paul Vogt
Kings Mountain, NC

 

[Jim L.]

Paul, can you get this fixed under warranty?

You need a Workshop Manual (WSM). Either buy from dealer or find an electronic copy ( may be listed as L3200 and L3800).

If it is the fuel injection nozzle, then pages 1S9, 1S17, and 1S55 are the ones you want to study.

Assuming that it is a clogged or out of spec nozzle, it is sitting under the fuel tank. So there is some disassembly to get a clear shot at the second injection nozzle.

You would need to remove and clean the nozzle and have it tested. A diesel shop should have the right test equipment and expertise. The spec is 1992 to 2133 psi. So it takes some setup, and can be a trip to the hospital if injected into the skin.

To put the nozzle back in you will need to read the WSM for correct torque.

 

[pvogt38]

Paul, can you get this fixed under warranty?

You need a Workshop Manual (WSM). Either buy from dealer or find an electronic copy ( may be listed as L3200 and L3800).

If it is the fuel injection nozzle, then pages 1S9, 1S17, and 1S55 are the ones you want to study.

Assuming that it is a clogged or out of spec nozzle, it is sitting under the fuel tank. So there is some disassembly to get a clear shot at the second injection nozzle.

You would need to remove and clean the nozzle and have it tested. A diesel shop should have the right test equipment and expertise. The spec is 1992 to 2133 psi. So it takes some setup, and can be a trip to the hospital if injected into the skin.

To put the nozzle back in you will need to read the WSM for correct torque.

Jim,
Thanks for the reply. Sadly, no warranty. All of this is on the right side of the engine, above the fuel pump. Three copper tubes leave here to bring fuel up to the top of the motor. I loosened the fitting on this 3-port thing I'm calling the injection pump. I'm assuming the "fuel injection nozzle" is downstream, one per cylinder. Please help me get the right terminology.
I'll take your advice and buy a WSM from my dealer, but from the numbers you mentioned, it sure sounds like a job for a Kubota mechanic. agree?
Paul

 

[Jim L.]

Paul, it's not rocket science and requires only a basic tool set.

Look on the top of the engine and you will see the three nozzles. Each has a pipe going into the top, and fuel overflow pipe going across close to the base.

The only technical step is taking the injection nozzle to a shop for test or setup, as the pressure needs to be in spec.

Everything else is taking pictures, keeping loose parts organized, keeping everything clean, and not dropping anything down the injection nozzle hole.

But only you know your mechanical ability and time value.

 

[rbargeron]

......this is on the right side of the engine, above the fuel pump. Three .. tubes leave here to bring fuel up to the top of the motor. I loosened the fitting on this 3-port thing I'm calling the injection pump. I'm assuming the "fuel injection nozzle" is downstream, one per cylinder. Please help me get the right terminology....

Paul, you have been clear and you have the terminology right - the injection pump has three outlet fittings located on top. The individual injectors are at the other ends of the pipes at 3 locations on the cylinder head.

Sounds like there's an issue with the injection pump not pushing fuel into the pipe through the pump's 3rd fuel delivery valve. The WSM may not be much help for this - they don't usually cover rebuilding the injection pump internals. May need to talk to a diesel injection service shop.

Possible causes include a fuel camshaft with a soft lobe that isn't actuating the pump, or (2) the pump is leaking backward and not making pressure. A dealer might replace the fuel cam or the pump with new parts - likely pretty spendy.

An injection shop might be able to service the pump - or if it's a bad cam there's an example on eBay at the moment.

It really needs a proper diagnosis by an injection shop and go from there.

 

[Jim L.]

rbargeron, thanks.

Paul, I am sorry. For whatever lapse I did not clue in to the injection pipes from the top of the injection pump to the injection nozzles.

So for an injection pump it may be more involved. You may find a good diesel shop nearby or you may have to ship it to a shop. The shims under the pump are very important as they relate to timing. See the WSM page 1S16.

Again, sorry to add to the confusion.

 

[pvogt38]

Jim L, and rbargeron,
Thanks very much for your coaching. It seems clear that my injection pump needs professional help. It's so nice to actually understand what is wrong with this tractor!! Like I said, I've been operating it for 6 months with no idea it was running on 2 cylinders.
uggh.
-paul

rbargeron, thanks.

Paul, I am sorry. For whatever lapse I did not clue in to the injection pipes from the top of the injection pump to the injection nozzles.

So for an injection pump it may be more involved. You may find a good diesel shop nearby or you may have to ship it to a shop. The shims under the pump are very important as they relate to timing. See the WSM page 1S16.

Again, sorry to add to the confusion.

 

[ShaunBlake]

Jim L, and rbargeron,
Thanks very much for your coaching.
...
Like I said, I've been operating it for 6 months with no idea it was running on 2 cylinders.
uggh.
-paul

Paul, welcome to OTT!

Hey, don't beat yourself up -- it's your L3800's fault! If she weren't so strong, you wouldn't have been fooled

One more thing: there are lots of tractor-porn Nazis who will get on your case, screaming, "Without pics, it didn't happen!" So to keep them at bay, it would be a good idea to take some pics of your project -- and please keep us updated on your progress!