803 Bogs Down and dies at 85% Load

[justacitizen]

the cut off solenoid should fully engage the lever on the governor housing when the engine is running and should fully disengage the lever when shut off. the governor controls the fuel rack that each metering pump is connected to. the governor should be adjustable for max speed. if the engine is running the load correctly and then bogs down while the load is constant and the governor is still wide open then you have a fuel delivery problem. most likely low primary pressure or plugging restricted fuel filters or return line. does the engine smoke black when it bogs down??? or does the power fade? after 15 min of 100% load???correct?

 

[USAMilRet]

So I placed the lever in the proper hole, lower of the two top holes. The cutoff now fully engages and disengaged and the genset now shuts down in about 2 to 3 sec instead of the 90 seconds it used to take.

No joy on tightening the fuel injectors to stop leak at shims.

When the rack moves from side to side, does it cause the fuel to be cut off immediately like an off on switch or is it like a dimmer switch - the more lateral movement the less fuel flow until it terminates flow completely?

Can the location of the rack cause fuel restriction in the injector pumps at higher demand while not causing a flow problem at lower demand?

 

[Guyfang]

So I placed the lever in the proper hole, lower of the two top holes. The cutoff now fully engages and disengaged and the genset now shuts down in about 2 to 3 sec instead of the 90 seconds it used to take.

Like I said, most problems arise due to fooling with the linkage without knowing what you are doing.

No joy on tightening the fuel injectors to stop leak at shims.

Pull the injectors and see if the copper washers are there. Or if there are two in the hole. Can happen.

When the rack moves from side to side, does it cause the fuel to be cut off immediately like an off on switch or is it like a dimmer switch - the more lateral movement the less fuel flow until it terminates flow completely?

The lateral movement lessens the amount of fuel sent to the cylinders.

Can the location of the rack cause fuel restriction in the injector pumps at higher demand while not causing a flow problem at lower demand?

No, can't happen

.

.

 

[jamawieb]

So I placed the lever in the proper hole, lower of the two top holes. The cutoff now fully engages and disengaged and the genset now shuts down in about 2 to 3 sec instead of the 90 seconds it used to take.

No joy on tightening the fuel injectors to stop leak at shims.

When the rack moves from side to side, does it cause the fuel to be cut off immediately like an off on switch or is it like a dimmer switch - the more lateral movement the less fuel flow until it terminates flow completely?

Can the location of the rack cause fuel restriction in the injector pumps at higher demand while not causing a flow problem at lower demand?

It's like a dimmer switch, as the lever moves to the left it slowly decreases the amount of fuel. If the rack was offset or the injector pumps were not fully engaged then you wouldn't be able to start or shut it down.
Please do this before you do anything else. Take the unit when it's cold and disconnect the hard fuel line on the fuel pump (the fuel pump is mounted on the left wall beside the radiator). Put a jar under the fuel pump where you disconnected the hard line to catch the fuel. Turn the dead crank switch to off, then go turn the master switch (where you start it) to Prime and run. Go back to the dead crank and move to on, now fluid will start coming out into the jar. Let it run for approximately 30seconds and measure how much fluid has filled the jar. Now do the same process after you put a 100% load on it and it shuts off. I bet you're going to see a lot less fuel in the jar when the pump is hot.
You can take the aux. fuel pump and move it to the primary pump to see if things change.
I had a unit that did the same exact thing as yours and it was the pump.

 

[USAMilRet]

Well it is under a 38% load at 240VAC each L pushing 120VAC , 21 amps on L3 and 22 amps on L1. My load bank is working fine right now.

Some bluish white smoke. Some wetstacking I think....Not heavy but some. Possible in rebuilt engine?

 

[USAMilRet]

My load bank top.....needs more switches and knobs....

 

[Daybreak]

Howdy,
Before you have everyone on the forums throwing guesses out...

You need to confirm a few things for proper assistance.

Did you change out all filters? (fuel cartridge, spin-on water/fuel, oil filter, air filter)
Have you drained any and all fuel from the tank?
Have you cleaned the tank?
Have you drained the oil?
8 hour unit, needs break-in oil.
coolent level? overflow tank?
fuel return lines OK?
batteries fully charged?
Run on "Prime & Run" for a while after all fuel filter changes...

Fresh oil
fresh filters
fresh diesel with additives

Does it run correctly now?

 

[USAMilRet]

Howdy,
Before you have everyone on the forums throwing guesses out...

You need to confirm a few things for proper assistance.

Did you change out all filters? (fuel cartridge, spin-on water/fuel, oil filter, air filter)
Have you drained any and all fuel from the tank?
Have you cleaned the tank?
Have you drained the oil?
8 hour unit, needs break-in oil.
coolent level? overflow tank?
fuel return lines OK?
batteries fully charged?
Run on "Prime & Run" for a while after all fuel filter changes...

Fresh oil
fresh filters
fresh diesel with additives

Does it run correctly now?

s

Yes, done with engine rebuild

Yes, done with engine rebuild

Yes, done with engine rebuild

Yes, done with engine rebuild
Filled with break in oil during engine rebuild
Filled, overflow bottle filled as appropriate
Fuel lines replaced but the return lines are beginning to crack so they will be replaced when I get the new hose later this week. Nothing is leaking though on the fuel system.
​

Fully charged
Fresh off road diesel, blue dye, can see to the bottom of the tank, no foreign materials.
No, it does not run correctly. As I was told by the rebuilder/seller the generator is supposed to bog down at about 85% load, but I have not gotten it to there yet.

Well, yesterday, I attached my home made load bank and ran the generator at 38% (22 amps drawn shown on meters) load for about 20 minutes. No issues what-so-ever. Decided to up the load to 60% (32 amps drawn shown on meters) and the gen ran fine for about 15 minutes then black smoke...knock knock knock… so emergency shut down.
Oil level is OK and I am really going to be pissed if I threw a rod in a newly rebuilt engine with less than 11 hours on it. Now the fault lights are indicating low oil pressure even though oil is full.

 

[jamawieb]

Sounds to me that it the fuel supply couldn't keep up with demand. What type of fuel pump do you have? Square design or Cylinder looking design? I doubt you did any damage, the knocking was more than likely not enough fuel in the cylinder to ignite while it was shutting down. The low oil pressure light is normal when the unit bogs itself down so far that it shuts off.

What color is the oil now? Syrup color or black?

I don't know why the rebuilder said it would bog down at 85% because the military load test these at 100% load for a couple of minutes after a rebuild. I've rebuilt a couple of these and will push them to 100% after a couple of hours of running at 50% load to break everything in.

 

[USAMilRet]

Cylindrical. I am going to put on a fuel gauge meter when it stops raining to see what the pressure is.

Oil is still blackish grey like when I got it. Well, I am going to change the oil and filter.

 

[m32825]

My fuel pump thread might be helpful:

MEP-803a AirTex fuel pump substitution

 

[jamawieb]

Cylindrical. I am going to put on a fuel gauge meter when it stops raining to see what the pressure is.

Oil is still blackish grey like when I got it. Well, I am going to change the oil and filter.

View attachment 735407

Did the guy do a total rebuild? If so the oil should still be a syrup (caramel) color. Now if he just changed the pistons and head gasket that's a different story.
Also, your oil leak around the injector pumps could be coming from the tubes for the push rods. I've had that happen before.

 

[USAMilRet]

Did the guy do a total rebuild? If so the oil should still be a syrup (caramel) color. Now if he just changed the pistons and head gasket that's a different story.
Also, your oil leak around the injector pumps could be coming from the tubes for the push rods. I've had that happen before.

My other thread shows a complete teardown of the engine in the pictures he sent me.

See here: https://www.steelsoldiers.com/showt...-It-Up-Today&p=2142822&viewfull=1#post2142822

 

[Guyfang]

I wish you luck in fixing this gen set.

 

[USAMilRet]

I wish you luck in fixing this gen set.

With your expertise, we should be able to get this thing up and running in no time. Have faith in at least my ability to type on the keyboard and explain what the problem is

I think these are just minor things.

In the latest news, I think that my fuel solenoid is bad now. Have to check it properly. If this thing has been jerking around back and forth, who knows what havoc it is causing. Worked yesterday, now today it is intermittent to hardly ever working.

 

[USAMilRet]

Low oil pressure light is still on and the gauge is only showing 5psi. Yesterday it was showing 22psi or so. But I can start the genset with no issues if I bypass the fuel solenoid and move the lever manually.

 

[Zed254]

Check oil sending unit and pressure switch wiring. I had a wire vibrate in two on an 802 one time.

3 wires at sender / switch:

Then check connections at gauge.

 

[jamawieb]

Ok, so it wasn't a total rebuild. He replaced rings, crank bearings, and head gasket. That explains why the oil is still black because he didn't get all the old oil out or didn't clean the bottom of the block real well. If the engine is able to make it to 80% and run fine, then quit after 15 minutes, it's not the motor but something else (Fuel pump, or could be the fuel cutoff solenoid). Usually if you have an internal problem of the motor you won't be able to get the set up to 80%.

To make sure it's not the cutoff solenoid, unhook and let the motor run without it, to see if it will get pass the 15 minute mark. But make sure you stay at the unit because if something happens it won't shut down.

 

[USAMilRet]

All tight. It is still only reading between 5 and 10 psi. Going through the checks right now.

 

[USAMilRet]

Ok, so it wasn't a total rebuild. He replaced rings, crank bearings, and head gasket. That explains why the oil is still black because he didn't get all the old oil out or didn't clean the bottom of the block real well. If the engine is able to make it to 80% and run fine, then quit after 15 minutes, it's not the motor but something else (Fuel pump, or could be the fuel cutoff solenoid). Usually if you have an internal problem of the motor you won't be able to get the set up to 80%.

To make sure it's not the cutoff solenoid, unhook and let the motor run without it, to see if it will get pass the 15 minute mark. But make sure you stay at the unit because if something happens it won't shut down.

I have not been able to get it to 80%. I only have gotten it to 60% load then it died. The rebuilder said 80%. Considering that there has been issues with the fuel cutoff solenoid as well as the injector pump rack via the fuel lever, stop/run, solenoid connection (which hole does it go into....the bottom of the upper two), and now it failing, this could be an indicator that it has been the fuel solenoid all along.

The oil pressure thing though, that is new though.