MEP-003 - Fuel Pump Issue?

[chiefgguy]

I have a MEP-003 and in the past couple of weeks have had a problem with the fuel pump. When in the Prime/Run position there is no "noise" from the fuel pumps.. In the Aux Prime/RUn it makes all kind of "noise".


Removed the first fuel pump, and pull the screen and careful to keep track of the magnet , and then put it back together and for "sh*ts & giggles" tried the prime/run position and it made noise. Then it stopped..


Not sure exactly where to go from here , i used the wrench and tapped on the MEP frame (not pump) and it started to make "noise"! While this was sufficient to get us up and running, I'd like to try and figure out how to fix it! After about an hour or so, the unit struggled with getting fuel, so we added some and it continued. Gently tapping the frame while running seemed to resolve the issue until we shutdown for the day..


My assumption is maybe there's some crud in there that needs to be further cleaned out or possible in pump #2. I did no take pump #2 apart.. THis unit has been pretty flawless for our off-grid cabin for the past 4 years, and we do run Diesel Kleen through it and the fuel doesn't sit very long before being used. (almost 1-2 starts every 2 weeks the unit is run quite regularly)




Additionally I have a question around the electric supply to these pumps, how does that wire come off there? It appears they are crimped, and if this is covered in a Field Service Manual I'm happy to go look it up. In the manual I currently have I didn't see it covered there. (I know there's a couple different manuals in the compilation set)

Thanks in advance for your advice/help.. This is has been a very helpful site for us to get to better understand our MEP over the past several years!

Andy

 

[EO2NMCB]

The wire for your power just pulls apart, that said the rubber is most times stuck together. I all ways twist the rubber first to break the bond, then pull apart. Mark all the power wires to the pumps, unhook all wires, then test each pump one by at a time to see which are bad.

 

[Guyfang]

If you are tapping the frame and it starts pumping, you need to start looking for a loose ground. The pumps should have star, or serrated washers holding them to the frame. Later models had a star washer mounted on BOTH sides of the electric fuel pump mount. Too many problems with crappy grounding. The bolts should be tight.

There is a possibility that there is crud in the pumps, but it sounds like a loose ground.

E-1 is the Aux electric fuel pump and E-2 & E-3 fuel pumps are the set fuel pumps. Wires P61C and P61E for to the set fuel pumps. Doesn't matter which pump is hooked to which wire. Disconnect these wires, measure DC voltage from the wire to ground when the S-1 switch is in the run position. You should get 24 volts on both. Wire P62E is the wire to the Aux pump. Repeat the test with the S-1 in the AUX position.

To test your pumps, you can connect a wire directly from the positive side of the battery, to the wire going to each pump. I would disconnect the output side of each pump to see if they are just not making noise, but pumping fuel. Hook them back up. See if it works.

 

[chiefgguy]

The wire for your power just pulls apart, that said the rubber is most times stuck together. I all ways twist the rubber first to break the bond, then pull apart. Mark all the power wires to the pumps, unhook all wires, then test each pump one by at a time to see which are bad.

Thanks EO2NMCB, i'll give that try, from a quick glance they looked sealed..

 

[chiefgguy]

Thanks for the insight Guyfang. I mis-spoke in my original thread, it would have been the E-2 & E-3 and E-2 is the one I took apart.

With regard to the ground, the bolts are tight and the aux (E-1) has not demonstrated the behavior. Since they are all mounted (at least it looks like) to the same bracket, I feel confident about the ground to this bracket. I did check the voltage to ground for both the wires going to E-2 & E-3, i took this measurement from before the "noise filter?" since I wasn't sure how to physically separate them.

I will follow your steps the next time I'm able to get back to the cabin and double check again the ground and connections.

Another question that i've got is regard to E-3, if E-2 is failed is the idea that E-3 should be able to "take over" or do they both need to function?

thanks for your advice!

If you are tapping the frame and it starts pumping, you need to start looking for a loose ground. The pumps should have star, or serrated washers holding them to the frame. Later models had a star washer mounted on BOTH sides of the electric fuel pump mount. Too many problems with crappy grounding. The bolts should be tight.

There is a possibility that there is crud in the pumps, but it sounds like a loose ground.

E-1 is the Aux electric fuel pump and E-2 & E-3 fuel pumps are the set fuel pumps. Wires P61C and P61E for to the set fuel pumps. Doesn't matter which pump is hooked to which wire. Disconnect these wires, measure DC voltage from the wire to ground when the S-1 switch is in the run position. You should get 24 volts on both. Wire P62E is the wire to the Aux pump. Repeat the test with the S-1 in the AUX position.

To test your pumps, you can connect a wire directly from the positive side of the battery, to the wire going to each pump. I would disconnect the output side of each pump to see if they are just not making noise, but pumping fuel. Hook them back up. See if it works.

 

[Guyfang]

Normally if one pump fails, the second can take up the slack. If you have fuel filters that are very dirty, this can be a problem. But if you have an E-2 or E-3 bad, and do not use AUX, just switch them out. When testing the pumps, we took them out, and bench tested them. The test being to fill a Qt bottle or can in about 60 seconds. More or less. Dumping some carb and injector cleaner in the tank every now and then is also a good idea. Good for the tank, electric fuel pumps, the injector pump, injectors and the check valve. Shooting some into the Aux system keeps the Aux solenoid clean also.

Where is Magnolia? I have a little Texas blood in me.

 

[chiefgguy]

Thanks Guyfang! Now that I have some context on things (Thanks to this thread), I'll do some more exploration when I'm with the MEP again..


Magnolia is North & West of Houston, North of Tomball and West of The Woodlands. The MEP sits in PointBlank, Tx, in between Huntsville, TX & Onalaska, TX!

 

[Guyfang]

Chief,

I have a brother in conroe, or better said, on Lake Conroe. Had grandparents in Wills Point, near Big D.

Glad to help. Let us know if it works, or what you found. It could help others.

Take care,

Guy

 

[Ray70]

Something else that maybe some of the more experienced guys could comment on: I seem to recall reading about an RF filter in the power wire on the fuel pumps. Possibly a small rectangular filter attached to the side of the pump?
Is it possible that he has some sort of intermittent problem with the filters ( electrical filter ) on his main pumps??
I thought I've read about guys either removing the problematic filters or maybe new pumps no longer have these filters on them??
( I just re-read this post before sending and see you mentioned "noise filter" so you do in fact have the RF filters on your pumps. Maybe they have a problem?)

 

[EO2NMCB]

When the noise filter on a pump goes bad, it will trip the DC circuit breaker on the front panel. The filter can be cut out and splice the wires and all will be good.

 

[Guyfang]

When the noise filter on a pump goes bad, it will trip the DC circuit breaker on the front panel. The filter can be cut out and splice the wires and all will be good.

Indeed! A good field fix. But you have anyone living close by, or you love your TV, Radio, or any other device that has a loudspeaker, it can sometime be a real pest when you hear the noise from the pump over the speaker. A small price to pay for electricity when no one has power, but it can cause problems with the neighbors.

 

[RJM27]

I have same and similiar problem, were is the best place to purchase these pumps???????? And what am I looking at for price? Just picked up Mep 003a out of leterkenny with 187 hrs, from a 2007 reset. Looks like it has set for a long time.
Thanks Bob.

 

[Triple Jim]

Indeed! A good field fix. But you have anyone living close by, or you love your TV, Radio, or any other device that has a loudspeaker, it can sometime be a real pest when you hear the noise from the pump over the speaker. A small price to pay for electricity when no one has power, but it can cause problems with the neighbors.

Very good post. Another consideration is emergency operation when ham radio gear may be nearby.

 

[chiefgguy]

thought i would update this thread with what I've done to fix my issue. I took the 2 primary pumps off and replaced them with the Aux pump. Wasn't too bad but getting some of the fittings off the Aux fuel pump presented quite the challenge. Thank goodness for a vice and PB blaster! I'm just running one pump now and will have a closer look at the other two. The screen and the general appearance was not that bad, so i'm thinking I'll take the clip out and dig a little further and see if the rod might need a cleaning.. thanks again for the advice offered on this issue, it was very helpful in furthering my understanding of this machine!

andy

 

[tbearatkin]

I cleaned my filter on the pumps with carb cleaner and then sprayed carb cleaner in the out fitting and let it soak. I also sprayed some in the center of the pump with the straw that came with the cleaner and moved the plunger in the center. I then took it outside hooked up the electrical and grounded it out on the frame and the pump took off. Seems to be have been just gunked up.

 

[Triple Jim]

Sounds about like my experience with this type of pump in other applications, tbearatkin. They're very simple, and there's not much to really fail, as long as you keep them clean enough to keep pumping.

 

[chiefgguy]

Well, my single pump seems to have only lasted a few months, according to my last post! So I now have 3 of the pumps that came with the unit that appear to have failed..I've pulled them all apart and did what i could but the only that got better was my ability to swap them out! So I ordered a Facet 40010 from Pegasus, and got it installed this past weekend and all is well again! I'm still puzzled as to all 3 of them being bad, with as simple as it sounds like they are.

 

[Triple Jim]

Any chance you can do a close examination and see what the cause of the failures is?

 

[rosco]

Those pumps are usually pretty reliable, for all three to go bad on the same machine.

 

[GREENMV]

Have you tried bench testing all three pumps? I am just curious.