MEP 802A No Fuel Fault Shutdown

[cuad4u]

Even though I have refurbished some 30 MEP 002A and 003A generators, I know very little about the 802A and 803A.

Recently (4 months ago) I bought a reset 802A with 4 hours showing. The paperwork indicates that a brand new engine was installed. Frankly the entire unit looks to be brand new.

When I got it home it started right up and ran perfectly. All I have done is crank it and exercise it once or twice a month and do a couple of load tests, all of which indicated the unit will easily pull 125% of rated load. The hour meter now reads 11 hours. I have run it 7 hours since I bought it.

Today when I started it up it ran about 2-3 minutes and shut down. The NO FUEL fault light came on. I reset the fault light and it cranked right up and ran another 2-3 minutes and shut down. This process repeated itself about 5-6 times before I gave up.

The fuel tank is FULL to the brim. All filters are new from the reset. There are no fuel leaks. All wires and connectors look to be OK. There is no mouse or rat damage.

The unit ran perfectly and as long as I wanted to run it for the first 7 hours I ran it. The fuel pump clicks and runs but it does not slow down after the fuel system is primed like the 002A and 003A. Is that a clue? Any info would be greatly appreciated as to where to start. I have downloaded the manual and have been looking for some clues, but I thought I would ask here as well.

Thanks

 

[Korgoth1]

Zarathusta(spelling?) had an article about the fuel level floats sticking. And guyfang has mentioned the guts can fall out of them. He mentioned looking in the tank first off for the guts, then moving on to remove the panel and test them.

 

[Korgoth1]

My pumps on the units Ive got run all the time aswell.

 

[jamawieb]

The fuel pumps on the 800 series will run at the same rate all the time unlike the 002a-003a. If it's an emergency you can hit the battle short switch and it won't shut down but it bypasses all safety features. The floats sometime get stuck causing the fault and sometimes the internals of the float system fall apart. The float system is very cheap to replace.

 

[Guyfang]

Morning all. First roll up your sleeve and remove the fuel tank cap and strainer. Then stick your arm down the filler neck and then stretch over to the middle of the tank. If your arm is too big, like man mountain dean, get someone else to do it. Feel around for a rod that goes straight up and down, with two cylinders, (floats) on it. They should move freely up and down. One, FL2, the top float, turns on the fuel pumps. FL1 is to turn off the set, for the no fuel, and turn on the low fuel idiot light. Often the floats stick and then You can have problems like you are experiencing. Make sure the bottom of the float assembly is NOT touching the fuel tank bottom. It can be adjusted. Read the book. But normally, its set right as long as its above the tank bottom. Get back with us if that's all good.

 

[cuad4u]

Thanks for all the good info. It is supposed to be COLD in SC this weekend. Since I have my trusty 002A and 003A generators ready to go if needed, I may (or may not) wait until the temperature moderates to stick my arm into the innards of the 802A fuel tank and feel around for the float. Since the fuel tank is FULL, I will have to pump some fuel out before trying to see if my arm will fit in the hole. If my arm goes into the tank but gets stuck and refuses to come out, I hope nobody will be looking. That could get embarrassing. When I do check the float as suggested I will report back on what I found. Thanks again.

 

[Guyfang]

If you don't want to stick your hand and arm in, or can't, (and yes, once or twice I thought I might not get my arm back out!) then remove the ten thousand bolts that hold the front cover on and simply remove the screws, (I think its 6 screws) and pull out the float switch. If your cork gasket is bad, or you screw it up, don't use RTV to seal it back up. Or at least not the RTV black. It turns into silly putty!

 

[cuad4u]

I promised to come back when I did some further checking on the brand new "reset" 802A.

To reiterate - I bought it about 5 months ago with 4 hours. It ran fine for the first 7 hours I owned it. Then it would start and run for 2-3 minutes and shut down. The NO FUEL light would come on.

Thanks to the help above I think I solved the problem. I keep the fuel tank FULL. I pumped out all but about 6 inches of fuel and carefully put my left hand and arm in the tank and felt around for the Z shaped float "thingie". When I felt it the bottom float was all the way UP as it is supposed to be when there is fuel in the tank. I "exercised" the float up and down the shaft for 10 or so ups and downs. Then I started the 802A and it runs like it is supposed to. Then I put my hand back into the tank and manually pushed the bottom float DOWN. The generator stopped within 5 seconds and the NO FUEL light came on. Then I started the generator several more times and it ran perfectly. I put about 2 hours on it today and no more problems.

Since the bottom float was UP when the NO FUEL light came on and shut the generator down, what could have been the problem? Is there a magnetic switch inside the Z shaped "thingie" that the bottom float activates when the fuel gets low? What would cause the NO FUEL signal even though the float was all the way UP?

Anyway thanks for the help. My 802A is running like the new one it is.

 

[Guyfang]

cuad4u,

Yes, there are three magnets in each of the floats. They close and open the micro switches in the Z thingie. Sometimes the top float can hang up because of that. Mostly happens when you fill up the tank, "just that last little bit", to keep out moisture. The screws that go through the mounting bracket are sometimes replaced with some that are a little longer. Or maybe the mounting bracket itself, is close enough to attract the magnets. If it happens again, remove the float switch. Remove the floats. turn the top float over and replace it. The magnets are only stuck into one end. If the magnets are on the top side, they could be too close to the mounting brackets/screws. A CECOM Rep once told me that's the problem.That's what I think happened several times to me. Also, sometimes little bit of "magnetic crud" can be picked up by the magnets and hinder the proper operation of the floats.

 

[WILLYSOVERLAND]

get a coat hanger and poke around the inside of the tank, the float is stuck.
that's what happened to me and that's what I did. its always something small and stupid

 

[zarathustra]

If you take the rear generator cover off to expose the tank -- and you probably will, simply unplug the wires coming from the sensor --- it is a molex connector with four wires going in and out.

Unplugging the connector simulates "tank full", and there should be no further problem.

Now, you will want to actually fix the problem, but with the connector disconnected you can test the generator to ensure that the problem isn't anywheres else.

Before I removed the sensor, I'd adjust it.

There is a constricting nut where the sensor tube goes through the fitting and into the tank. Loosen that nut and the sensor will slide up and down. Note the original position (depth) of the sensor and after moving it up and down a few times, re-position it so that the sensor is around 3/16 to 1/4 inch higher than it initially was. Tighten the constricting nut, plug the connector back in and fire the unit up and test. If the sensor is too deep into the tank, that float can bind with the tank where it makes that ~1.5 inch vertical turn.

Chances are you are good to go after that.

 

[clampet86]

I just recently have had this problem with one of my 802's and have done a little troubleshooting today and thought I might share some of my findings. So to start off I just picked up this 1994 with 400 hours on it and put fluids in and started it up and ran it for a few minutes to let things warm up and and make sure nothing was leaking especially the fuel lines as that has been a constant problem with almost all the others that I have picked up. I checked the frequency and voltage on the lines and then shut her down. Today I got it out to load test and ran into the no fuel light problem. I hadn't put much fuel in so I added some and thought that would solve the issue...not the case. So I remembered having read a couple of threads that had this same issue, so i jumped on here to refresh. Done all the simple tests like checking the floats and make sure they weren't stuck. I had to twist the sensor tube so that the bottom float wouldn't get caught on the filler neck housing and thought my problem would be solved..nope. Checked the upper float to see if it was moving freely and it was. The fuel level was just at the bottom of this float so not enough to raise it. So, I took off the front panel and checked the continuity of the pins as it states in the TM. Continuity was good assuming I chose the right pins to test since they aren't numbered and the wire colors are deceiving. The genset starts with the plug undone so I ran my load test and she ran good at just under 27 amps on L1 and L3.

After letting it sit for awhile I got to thinking of starting the set with the connector plug undone and then plugging in the connectors while holding the upper float in the up position to achieve the open circuit. It worked. I let the float go to see if it would die and it didn't, she just kept on running. Hopefully this insight might help others that are working with this mysterious problem why it works some days and not others when there is obviously fuel in the tank.

I don't know why the upper float is sending the signal that there is no fuel though. From what I understand is that that float is to operate the Aux Fuel pump if you are running that way. Also another interesting point is that the no fuel light doesn't come on the first time I put the switch in prime and run position but only when I try starting it, but every try after that it comes on in the prime and run position and kills the pump.

I guess my question now is if I should try the suggestion from Guyfang to pull the switch out of the tank and pull floats off and turn the upper float around the other way to see if that will work any better. Any suggestions are welcome, and thanks for all those who have already helped me so much in this forum.

 

[dav5]

You might want to check the big auction site. I wouldn't be surprised if you found a NOS sending unit for about $30 right now. For that amount I wouldn't waste time fiddling with a suspect sender that could fail at any time.

 

[DieselAddict]

+1 on Dav5's advice. Replace it. I've spent far too long messing around with these **** things. Once they develop an intermittent fault the problem is usually in the reed switch. You'll waste a bunch of time and end up replacing it in the end.

Unless you enjoy torturing yourself. If so, carry on!

 

[Daybreak]

Howdy,
Not so fast.

Fill the tank, slosh it around and load test your unit. Since it is a MEP-802A, you will get all those nice vibrations which might help unstick some things. A good additive will help here too.

Get things all in the tank and fuel system working smoothly.

 

[Guyfang]

Now you have heard it all. And I think you have good advice here.

While you are waiting for a new one to arrive, try filling the tank and running it for a few hours under load. The reed type switches, no matter what type gen set, never made anyone really happy. The idea is good. Design is good. But for some reason, they gave us problems for ever. Even if it does start to work right, at some time it will probably fail again.

Strangely enough, in the early 70's, the holes in the floats were a little bit bigger. There was just a tad more room for the float to go up and down on the guide. It seemed to me, that we had fewer problems. Different gen set, but the principle is the same. Of course we were using different fuel, JP-8, later with the TQG's. But for the civilian world, that's not a factor.

If you do replace it, take the old one apart. I assume they haven't changed the design. It should come apart, easy. If it does, you should find two glass bulbs with contacts in them, that the magnets in the floats open and close. You might find one or both contacts has problems. I fooled with them over the years. Even "fixed" one or two. Getting the RTV out of the tube was a PITA. But never really trusted them. Sometimes its just a bad solder job.