Mep 003a fuel pump connectors

[DieselAddict]

To jump ahead a bit, have you turned the engine over yet? If you haven't, thats good. Once you have fuel pumps figured out, you'll need to verify that the injection pump is free. You should remove it and free it up before you start it. Failure to do this will damage the pump. Its not the end of the world but better to avoid if you can.

 

[Brother Hec]

You should be able to download them. Try again. Sometimes there can be temporary glitches with Internet apps. You may want to close everything out in your browser and then the browser itself to reset security and permissions.

If you still have problems one of the moderators will look into it.

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[rickf]

Dors anyone know what’s the failure mode on this electronic part? Just curious.

If you are talking about the filters the failure mode is they simply stop passing voltage. They are a capacitor.

 

[Brother Hec]

To jump ahead a bit, have you turned the engine over yet? If you haven't, thats good. Once you have fuel pumps figured out, you'll need to verify that the injection pump is free. You should remove it and free it up before you start it. Failure to do this will damage the pump. Its not the end of the world but better to avoid if you can.

Thank you for your thoughts. You are right about the injector pump. My genset was turning over when pumps failed. Pump worked (made noise) at prime/run switch position, After pump stopped working (no noise) , no fuel flowing in lines leading to injection pump confirmed by cracking fittings and opening them up.

 

[Evvy Fesler]

Thank you for your thoughts. You are right about the injector pump. My genset was turning over when pumps failed. Pump worked (made noise) at prime/run switch position, After pump stopped working (no noise) , no fuel flowing in lines leading to injection pump confirmed by cracking fittings and opening them up.

Have you gone through the fuel system to make sure the fuel is reaching the engine without dirt, water or air?

 

[Brother Hec]

Have you gone through the fuel system to make sure the fuel is reaching the engine without dirt, water or air?

Thanks. Working on that now.

 

[Evvy Fesler]

Thanks. Working on that now.

In hindsight I probably should have suggested you start with fuel and normal preventive maintenance. The idea is to get all of the normal stuff out of the way so it doesn't make you go down the wrong path, troubleshooting, which can consume needless hours of your time.

 

[Brother Hec]

In hindsight I probably should have suggested you start with fuel and normal preventive maintenance. The idea is to get all of the normal stuff out of the way so it doesn't make you go down the wrong path, troubleshooting, which can consume needless hours of your time.

 

[rickf]

Evvy, Have you read this thread from the beginning? The very first post was the OP asking for help diagnosing his fuel pumps which are NOT working! So he KNOWS the engine is not getting any fuel and that is why he is here. Please give him a chance to solve that issue first. And I realize you are trying to help but just so you know, piercing a wire with those probes is a very bad idea! Once the insulation is compromised moisture starts to get in there and in a few months you will be able to cut that wire off an inch up from the hole and find corrosion growing on the outside of the wire. Green death. Electricity travels on the outer surface of the wire and once corrosion starts so does resistance. Always check for power at a connection.

 

[Evvy Fesler]

Evvy, Have you read this thread from the beginning? The very first post was the OP asking for help diagnosing his fuel pumps which are NOT working! So he KNOWS the engine is not getting any fuel and that is why he is here. Please give him a chance to solve that issue first. And I realize you are trying to help but just so you know, piercing a wire with those probes is a very bad idea! Once the insulation is compromised moisture starts to get in there and in a few months you will be able to cut that wire off an inch up from the hole and find corrosion growing on the outside of the wire. Green death. Electricity travels on the outer surface of the wire and once corrosion starts so does resistance. Always check for power at a connection.

I don't disagree with you on piercing probes. The hole needs to be sealed and I should have said so.
I did read from the beginning, in fact, I've followed him all along. When we got to this post, it was worth the mention.

"Thank you for your thoughts. You are right about the injector pump. My genset was turning over when pumps failed. Pump worked (made noise) at prime/run switch position, After pump stopped working (no noise) , no fuel flowing in lines leading to injection pump confirmed by cracking fittings and opening them up."

While it's possible that a solid state EMI filter opens (coil) or shorts (capacitor) and redundantly (two of them) given the additional information above, I believe it's best to quickly confirm voltage at the pumps and go back to basics to eliminate clogs as a suspect.
Or... just buy two EMIl filters and two pumps and see if the pumps clog up again. I suppose it just depends on how much money one has to spend.

 

[87cr250r]

"Electricity travels on the outer surface of the wire and once corrosion starts so does resistance."

Skin effect is only at very high frequencies and with AC power.

Skin effect - Wikipedia

en.m.wikipedia.org

With that said, corroded wires are never a good thing.

 

[rickf]

Two things, One is we are NOT dealing with AC power but DC power and two, Wikipedia is not exactly the most dependable source of knowledge out there. When I had my shop one of my specialties was automotive electrical so I got to see my share of corroded wiring. This was before glue sealed crimp connectors so I saw a LOT of it. And the infamous boat trailer wire connectors. I have seen entire rear wiring harnesses gone bad because of those boat connectors. The wires corroded 10 feet or more all the way to the front of pickup trucks inside of the insulation. It starts on the outside of the wire and as the resistance builds up so does the heat and the corrosion follows the heat into the center of the wire.
As far as replacing, the last price I saw on those pumps was approaching 400.00! EACH!

 

[Guyfang]

Have patience. Someone will answer. Better pictures will help.

I posted in another thread, where you asked this question. Did you read that post?

I did not mean Evvy. I meant Brother.

 

[Guyfang]

You posted this in another thread. Something you are not supposed to do, post the same problem in several threads.
Below is my answer.

I have a MEP-003a with pencil style emi filters on electrical feed to OEM fuel PUMPS 24volt. My problem is that fuel pumps stopped working and I would like to check for juice at pump. However, these pumps have connectors I can’t remove. I am not familiar with connectors. Can you tell me how to remove them at the pencil emi filter upstream from pump?? I would like to avoid cutting line to test pumps. I want to test emi filters rather replacing a pump.
thank you for any help.

You cant. They are a non removable thing. Is this gen set new to you? Or have you seen it work right before. By " My problem is that fuel pumps stopped working " what do you mean? One pump stopped working? Both pumps stopped working? The Aux pump also stopped working?

I suppose you could unsolder them, maybe. I never tried that.

Have you tested at the removable connection, for 24 volts? If you have 24 volts at the female connection, and the pumps do not work, AND IF they worked before, then 99.00% chance its the filters. Simply cut them off, and rehook them up. Broke is broke. The only way to test would be to cut the wire. But first, before you get to that point, the questions above would be good to answer.

If you never saw/heard them work, then it could also be a case of them being clogged up, or the fuel lacquer has frozen the pumps up. Simple to correct

 

[Guyfang]

Now, lets talk MEP-002A and MEP-003A fuel pumps.

There are two fuel supply 24 VDC electric pumps on your gen set. There is a third on the set, for using Aux fuel position when in the S1 (start switch) position, "Run, Aux". You need to be in the normal run positin to make your two pumps run. Why are there two pumps? Because if one pump fails, the other pump can continue to provide fuel to the engine. These are special pumps. They are designed to "Pass" fuel through a dead pump. There are pumps that look just like these pumps, but will not do that. So, if there is a wrong pump in the system, you get no fuel to the engine. The two fuel pumps that provide fuel to the engine are E2 & E3. The Aux pump is E1.

A quick way to check out your pumps is like this.

1. Push in the CB2, (DC circuit breaker)
2. Turn the S1 to the Run Aux position. Do you hear a pump run? If so good.
3. Follow all three wires from all three fuel pumps to the rubber connectors.
4. There are metal tags on the wire harness female ends, (Fat side of the connection). The wire numbers for E2 & E3 are P61C and P61E. The wire for the E1 is P62E.
5 Disconnect all three plugs. Follow steps 1&2. The female end, P62E should be hot. Check it with your multimeter.
6 Connect P62E to the other two pumps, one at a time. Do the pumps run? If so, then your pumps are good, and you have another problem. If the pumps are dead, then you need top remove them and try cleaning them. They may be gummed up. The attached picture is how the pumps come apart. Try this before cutting wires. If cleaning is not the problem, THEN go to cutting out the EMI filter. There is really no need for them in todays day and age.

 

[Guyfang]

The rubber connectors do pull apart but you will probably have to twist them a bit to get them going. My guess is that one of the pumps is probably gummed up and that is why it is not running. These pumps are pretty robust and seldom go bad. It does happen but more often they stop working due to varnish and gunk in the pump. You need to pull the bottom cap off the pump to check the internal filter and then you can take it apart from there but as has been said it is best to read all the manuals before you go to far. I am the last guy to say RTFM but with this military equipment if you are not familiar with it from actually running it in service then you have to read the manuals. There are all kinds of little tricks that you would not think of like holding the start switch for a period of time after the engine starts to make sure the generator gets a field current. Both pumps should run but if one has a clogged line or is gummed up then a power test will show normal.

Yes, but more no. As explained above, if one pump fails, the other can pump through or draw through, a dead pump. Never seen a clogged line, but suppose its possible.

Open to see comment

 

[Guyfang]

Dors anyone know what’s the failure mode on this electronic part? Just curious.

Evvy, this is a very common failure, even when the pumps were new. Most are older then St. Peter now, and its fairly common that the EMI filter goes bad. The pump itself is cast iron. Few pumps fail. It happens, but mostly if they stop, its plugged up or EMI filters.

 

[rickf]

Guy, I had a plugged line take out both pumps. It was actually a plugged filter in pump two. Pump two quit working probably due to heat from running dry, it just bound up. Pump one did not go bad but did not run since it was blocked by pump two. A good cleaning of both pumps AND the fuel tank solved the whole problem. I even took the aux pump apart and cleaned it out and lubed it up with light oil for good measure. You can always use that pump as a spare with some creative rerouting of the lines to get you by till the others are back online. Yep, been there, got the shirt.

The interesting thing about that whole scenario is how did pump two filter clog before pump one?

 

[Evvy Fesler]

Evvy, this is a very common failure, even when the pumps were new. Most are older then St. Peter now, and its fairly common that the EMI filter goes bad. The pump itself is cast iron. Few pumps fail. It happens, but mostly if they stop, its plugged up or EMI filters.

St. Peter? Wow, that's pretty old!

 

[Evvy Fesler]

Guy, I had a plugged line take out both pumps. It was actually a plugged filter in pump two. Pump two quit working probably due to heat from running dry, it just bound up. Pump one did not go bad but did not run since it was blocked by pump two. A good cleaning of both pumps AND the fuel tank solved the whole problem. I even took the aux pump apart and cleaned it out and lubed it up with light oil for good measure. You can always use that pump as a spare with some creative rerouting of the lines to get you by till the others are back online. Yep, been there, got the shirt.

The interesting thing about that whole scenario is how did pump two filter clog before pump one?

Is there a fuel filter inline with each pump?