MEP 803a No Fuel Light - One possible problem and solution

[bridaus]

Did a search, didn't find my problem, and hoping the solution helps someone.

My issue with a newly received MEP 803a was that the fuel pump would run for about 2-4 seconds and shut off with a no fuel light. There was plenty of fuel and the gauge showed greater than half a tank as well. I initially felt inside the tank for the floats, and felt the top one was fine and floating.

Well, there are two floats. After I felt for the second and found it, seemed to be stuck at the bottom. Careful poking with my hands, seemed it was wedged against the side of the tank. After carefully prodding, I twisted the assembly in the tank, and the bottom float pulled away from the side of the tank and freed up.

So essentially, the bottom float was stuck at bottom (and the top was not), which signals no fuel even though gauge shows full, and stops engine from starting.


I'm sure those with the technical expertise know where in the manual it says to check this, but I could not find anything.


PS: My theory on cause is that a small amount of fuel in an empty tank sloshes back and forth OR jarring during shipping (slamming against truck wall) spins the float around an axis where the tube enters the tank, and wedges the assembly against the tank wall.


Hopefully this post helps someone searching for a fix for a persistent No Fuel light even with plenty of diesel in the tank physically and shown on the fuel gauge!

 

[impi]

The float gauge position is adjustable.The collar that holds the sensor tube at the top can be loosened and the tube itself can be adjusted. There's a few obstacles it can get hung up on inside the tank - the fuel pickup is one, the side of the tank is the other.

 

[paine]

Funny that you posted this issue, at the moment I am having a similar issue (opposite). The last power outage I had a power surge from the 803 before it ran out of fuel, it did not trip the low fuel light / shutdown. I also felt around in the Tank for the lower float switch and it also seems like it is touching the lower/bottom of the tank.

I was was planning on taking the covers off the unit and adjusting the float assembly... are you saying you were able to adjust the float assy. from inside the fuel door area?

 

[paine]

The float gauge position is adjustable.The collar that holds the sensor tube at the top can be loosened and the tube itself can be adjusted. There's a few obstacles it can get hung up on inside the tank - the fuel pickup is one, the side of the tank is the other.

Looks like a partial answer to my question, so I should go ahead and take the cover off and loosen the collar?

 

[Guyfang]

to properly adjust the float, remove the cover to the tank area. Then loosen the collar nut on the float assembly. Then look into the tank with a mirror, or simply stick your hand into the tank and feel the gap between the float and the bottom of the tank. Then make sure the float is turned away from the side of the tank and the pickup tube. Now, you look in the TM and find out what the gap is between the tank bottom and the float. Good training.

 

[paine]

to properly adjust the float, remove the cover to the tank area. Then loosen the collar nut on the float assembly. Then look into the tank with a mirror, or simply stick your hand into the tank and feel the gap between the float and the bottom of the tank. Then make sure the float is turned away from the side of the tank and the pickup tube. Now, you look in the TM and find out what the gap is between the tank bottom and the float. Good training.

Awesome, I’ll mess with that tomorrow! Thanks!

 

[paine]

to properly adjust the float, remove the cover to the tank area. Then loosen the collar nut on the float assembly. Then look into the tank with a mirror, or simply stick your hand into the tank and feel the gap between the float and the bottom of the tank. Then make sure the float is turned away from the side of the tank and the pickup tube. Now, you look in the TM and find out what the gap is between the tank bottom and the float. Good training.

****! I have been searching the TM’s for over an hour and I can’t find the float switch info!

 

[impi]

****! I have been searching the TM’s for over an hour and I can’t find the float switch info!

TM-9-6115-642-24
Change 1 Page 2-105
section 2-77.4

 

[Guyfang]

TM-9-6115-642-24
Change 1 Page 2-105
section 2-77.4

View attachment 726383

Impi,

You are way too nice. Got to make him sweat a little. This was supposed to be "Good Training". You should have asked what TM he was using first. Oh well, spare the rod,..............................................................

 

[impi]

I'm catching on....

Impi,

You are way too nice. Got to make him sweat a little. This was supposed to be "Good Training". You should have asked what TM he was using first. Oh well, spare the rod,..............................................................

 

[paine]

I'm catching on....

Yeah I know what he was getting at, but thanks for helping the slow guy!

 

[Guyfang]

Then we have progress!!

 

[paine]

So I finally found some time to dig into the float issue and I can’t figure out what the proper orientation of the float assembly. I did read the TM and it’s main reference to the orientation of the assembly is “same as when removed”. Any chance someone can post a pic of the float from the filler neck?

 

[dav5]

A photo from the filler neck isn't going to show you much. The important dimension is 1/16 inch from the bottom for the lower float. The upper float on mine is barely below the 90 degree bend in the tube. If the floats aren't in the correct position loosening the collar and lowering the assembly won't work. You will have to remove the assembly and move the c clips that hold the floats. If you do a search there are photos of the assembly removed.

 

[impi]

So I finally found some time to dig into the float issue and I can’t figure out what the proper orientation of the float assembly. I did read the TM and it’s main reference to the orientation of the assembly is “same as when removed”. Any chance someone can post a pic of the float from the filler neck?

Best I can explain is if you regard the fuel pickup as 12 o’clock in relation to the float then the orientation is in the 10-11 o’clock orientation. The way i aligned mine was to stick it in the whole, rotated to the right until it hit the pickup, rotated left until it hit the tank, split the difference and left it there. I only loosened the collar enough to allow me to swing it, but not so much as to adjust the height.


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[dav5]

The height adjustment is important. Don't rely on "where it was when you checked it". Most of them are set wrong. It is an easy adjustment

 

[impi]

The height adjustment is important. Don't rely on "where it was when you checked it". Most of them are set wrong. It is an easy adjustmentView attachment 727430

Height adjustment is irrelevant if the float pushes against the fuel pickup or side of the tank which interferes with ability of float to move. It is secondary to making sure the floats can actually float freely.


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[dav5]

That is very true but if you are at the stage where you can adjust the height how much longer would it take to take 5 screws out and inspect the sender. If you do a search you can find out how to use a multi meter to see if it is defective, you can clean the crud off the tube so the floats can move freely.

 

[dav5]

https://www.steelsoldiers.com/showt...-803a-when-there-is-actually-fuel-in-the-tank. Here is a link to a post from Zarathustra I found very helpful.

 

[paine]

Thanks for the help guys! It really is a simple job but I was trying to keep it close to how I found it so I end up with the floats very close to the fuel fill tube holder deal. At the moment I cannot picture what the fuel pickup is as I am not out by the unit but if you call the side/radiator 12 o’clock then the only spot where I can get the floats not touching bottom and not hitting the fuel fill tube is right around 11 o’clock. I will check it out again tomorrow, the cover is still off as I am going to wait for some new fuel return line and new well nuts to show up. A lot of people around me are without power from a recent storm and normally I would be jealous, not this time! Thinking back, I guess I should have started a new post about this! I may have a oil leak/seep from the case cover just under the oil filter, after I confirm I will start a new post.

Thanks!!