MEP-802a no fuel light problem

[hammick]

I have a new to me MEP-802a and it runs great. However it periodically shuts down and the "no fuel" light comes on even though it has fuel. It is clear a mechanic was working on the fuel system evidenced by all the missing screws on the fuel side panel.

Sometimes it will run for a half hour before shutting down. Other times just a few minutes. I have read the posts about the sending unit float. What doesn't make sense is how this can be a sporadic problem. I would think if the float was stuck at the bottom it wouldn't start. It always starts easily after it shuts down.

I already have the tank side panel removed. What is the best way to troubleshoot/fix this problem?

Thanks.

 

[Daybreak]

Howdy,
TM 9-6115-641-24 start on page 387

 

[hammick]

Thank you. I have two TMs for the 802 and neither cover this procedure. I'll download the one you referenced.

 

[kloppk]

Deleted..

 

[Guyfang]

Cats out of the bag.

Hammick, Go to the TM section and download all he manuals there you need to work on your set. Some other good stuff there also.

 

[cuad4u]

I bought a reset 802A with 4 hours showing in the summer of 2015. I never really used it but played with it. Right now it has 17 hours. It ran perfectly until February 2016 when I started having the exact same problem - low fuel light coming on and engine shutting down - even though the tank was full of fuel.

I posted here and got lots of info. The low fuel float was not stuck in the DOWN position. It was a close fit but I could get my hand inside the tank and feel the float. It was free and working perfectly. With the generator running I could manually pull the low fuel float down to simulate a low fuel condition and the engine would stop in a few seconds.

I could not find anything wrong. After having the problem for around two months, it went away just as mysteriously as it came.

My 802A is working perfectly now. I will always wonder why and when it may happen again.

 

[hammick]

I won't be able to dig into mine until Tuesday but my thinking is if the mechanism is more than 1/16" of an inch off the floor of the tank it would make it more likely that the float could vibrate down. My gauge is showing 3/4 full. I have a bottle of Supertech fuel injector cleaner in the tank. Not sure if that could change the buoyancy of the fuel.

 

[Guyfang]

Its a problem that is universal, and always seems to drive people crazy. Check how far from the tank bottom the switch is. Thats a good place to start. Like cuad4u, reach in and move the switch. Supertech will not hurt anything. Look at the electrical connections. Also, when you reach into the tank, feel the floats. Sometimes the float material just falls apart. The JP-8 the military uses tends to erode it.

 

[hammick]

I fixed my "no fuel" shutdown problem today. My dual float switch was probably 1 1/2" off the bottom of the tank. The TM spec is 1/16". My switch was in good shape and looked new. It probably was since it was clear they were trying to fix a fuel related issue and gave up.

The assembly does not need to be removed to adjust. Simply loosen the locknut (counter-clockwise) and the assembly can be moved up and down. Remove the gas cap and filler filter and have a good flashlight. Make sure the assembly is positioned correctly and then push it down until it hits the bottom of the tank. Raise it up 1/16" and tighten the locknut.

Attached is a photo of the assembly.

 

[Daybreak]

I fixed my "no fuel" shutdown problem today. My dual float switch was probably 1 1/2" off the bottom of the tank. The TM spec is 1/16". My switch was in good shape and looked new. It probably was since it was clear they were trying to fix a fuel related issue and gave up.

The assembly does not need to be removed to adjust. Simply loosen the locknut (counter-clockwise) and the assembly can be moved up and down. Remove the gas cap and filler filter and have a good flashlight. Make sure the assembly is positioned correctly and then push it down until it hits the bottom of the tank. Raise it up 1/16" and tighten the locknut.

Howdy,
That is the float system which controls a few things. The No Fuel "Fault Indicator". It also works with the Aux Fuel pump. When to turn it on for aux fuel, and when to then shut the aux fuel pump off.
Switch liquid level 5kw NSN 6680-01-450-6330 part# 88-20481
View attachment 619826
You also have the Fuel level float, which sends the level to the front panel fuel gauge.
Switch liquid level 5kw NSN 2910-01-366-8985 part# 88-21162-1

The top of the MEP-802A fuel tank.


NOTE: GASKET; The military at least did not try and re-invent the wheel. It's used on a lot of things.
Gasket NSN 5330-01-366-2836 part# 88-20286
or/ in the civilian world, a fuel sender gasket SAE 5 hole

 

[Guyfang]

You guys are on the ball!

 

[Zebcorod]

This thread has been very helpful when our MEP-802A no fuel fault light came on yesterday morning. I now know i need a dual float Switch liquid level and gasket. I just found one online for $40. Thanks again Steel Soldiers forum!!! I would be lost without you guys.

 

[Daybreak]

This thread has been very helpful when our MEP-802A no fuel fault light came on yesterday morning. I now know i need a dual float Switch liquid level and gasket. I just found one online for $40. Thanks again Steel Soldiers forum!!! I would be lost without you guys.

Howdy,
Double check your float first. Reach in and manipulate it up and down. Undo the wires and put a ohm meter on it and watch the readings as you move the float. You might not need a liquid level switch. The gasket is a standard SAE 5 gasket. Check with your local auto parts store.

 

[Guyfang]

Indeed, sometimes the floats stick, due to crud and dirt. Can't hurt, might save you some money.

 

[Zebcorod]

Thanks for the tips Guyfang and Daybreak! I will check it out.

 

[Grizzlypower2001]

I have been reading and trying to find an answer. I never had an issue with the low fuel light, till today. I have run my 802 numerous times ( never more than a couple hours at a time) and getting it ready for a load test. It had just below 3/4 tank on the gauge so I topped it off with fuel, it took a five gallon can. I went to start it and shut down with the low fuel light, reset and did it again. I fired it up, hit the battle switch, low fuel light came on, waited a minute, reset the light and was fine for the next few minutes till I shut it down.

My question is, could filling it up cause this? The fuel is almost covering the very bottom of the strainer. Or is this the beginning of a failing float switch.

Thanks for you help guys.

Sent from my XT1254 using Tapatalk

 

[Guyfang]

Grizz,

It could very well be. I would pull the float switch out and move the float, or floats, by hand. See if it goes out, or not. Don't forget, once the light comes on, you have to hit the fault reset switch, to so if moving the float changed the low fuel light comming on. Best to get your willing, cheap laborer, like a wife of offspring to assist you in this endeavor.

 

[Grizzlypower2001]

Grizz,

It could very well be. I would pull the float switch out and move the float, or floats, by hand. See if it goes out, or not. Don't forget, once the light comes on, you have to hit the fault reset switch, to so if moving the float changed the low fuel light comming on. Best to get your willing, cheap laborer, like a wife of offspring to assist you in this endeavor.

Thanks for the quick reply. Did the first load test today and she did good. The issue with the low fuel light did not return while working her.

When I first got it I wiped the tank clean and remembered reading on these and did play with it while it was empty. It's mind boggling to me, never seen it before. It wasn't near empty, I just topped it off perhaps a bit too much if that's possible.

Thanks again!

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