MEP-003A

[rlegare44]

I have an MEP-003A Diesel Gen. Master switch will turn engine over, but will not make prime, or Prime run noise, so I assume the fuel pump is not working. Have checked everything except replacing anything. Worked when first attempted but then quit. Solution anyone?

 

[Scoobyshep]

Find the 2 main fuel pumps (one is to fill the tank). There is a quick disconnect, unplug it and see if you have 24 volts to chassis with the switch in run. If you have power pump needs help. No power we gotta dig deeper.

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[Ray70]

If it hasn't been run in a while and you have 24V at the pumps as Scoobyshep mentioned, the internals of the pumps are surely gummed up and stuck.
They are 99% of the time pretty easy to disassemble clean and be good to go again.
If by chance you still have issues I usually have rebuilt pumps available.

 

[Guyfang]

After checking for 24 volts at the female E-Pump plug, if you have 24 VDC take a wire and jump from the positive battery terminal to the male E-Pump plug. If it wont run, the problem might be the RFI capacitor. Cut it out of the cable and splice the cut off cable back on the wire that goes to the E-Pump. Retest. Run? Then it was the RFI Cap. Not run pump is bad.

 

[rlegare44]

Find the 2 main fuel pumps (one is to fill the tank). There is a quick disconnect, unplug it and see if you have 24 volts to chassis with the switch in run. If you have power pump needs help. No power we gotta dig deeper.

Sent from my SM-S908U using Tapatalk

Opened both fuel pumps, filters clean and with air hose, air flows freely through lines. Have a 24V reading at the quick disconnect. Still no sound from master switch that pumps are priming. Never had this happen before out of 49.

 

[Scoobyshep]

Opened both fuel pumps, filters clean and with air hose, air flows freely through lines. Have a 24V reading at the quick disconnect. Still no sound from master switch that pumps are priming. Never had this happen before out of 49.

If you have 24volt at the quick disconnect wother the suppression capacitor is burnt out, the pump is jammed, or the pump is burnt out.

The capacitor can be removed and bypassed (see Guys comment above).

The pump needs further disassembly and cleaned

Or pump needs replaced


The disassembly and cleaning is very easy and I prefer taking it to a work bench. Remove the end cap and filter, there is a check ball in a tube, remove the retainer clip (be careful there is a spring behind it). Remove ball assembly and spring. There is a long metal plunger past the spring. This will get gummed and jammed. Ive had them come out as easy as a few taps on the top, and as hard as blowing 120psi of compressed air through the pump discharge (plunger launch imminent). After my ears stopped ringing and I was able to dig the plunger out of the Sheetrock, I cleaned it with brake parts cleaner and got it moving smoothly in the bore. Reassemble and test.

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[Ray70]

By cleaning the filter and blowing air through you have only done 10% of the job.
You have to remove the funny clip, take out the check ball assembly and then knock out the plunger and spring assembly.
99% of the time if it's not clicking it's because the plunger is gummed up and unable to float freely within the center tube.

 

[Ray70]

Scoobyshep types 10 seconds faster than me...

 

[Scoobyshep]

Scoobyshep types 10 seconds faster than me...

And 56% funnier

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[rlegare44]

After checking for 24 volts at the female E-Pump plug, if you have 24 VDC take a wire and jump from the positive battery terminal to the male E-Pump plug. If it wont run, the problem might be the RFI capacitor. Cut it out of the cable and splice the cut off cable back on the wire that goes to the E-Pump. Retest. Run? Then it was the RFI Cap. Not run pump is bad.

If the pumps a clogged, does that prevent the master switch from clicking? Just trying to understand the working sequence.

 

[Scoobyshep]

If the pumps a clogged, does that prevent the master switch from clicking? Just trying to understand the working sequence.

The switch should only click once per position you move it to, from what you described with 24 volt to the pump qd and no noise indicates a pump problem.

A clogged pump may click very slowly. A gummed pump won't click at all.

What you are hearing with the clicks is the plunger inside slamming back and forth from spring pressure and electromagnetism.

 

[rlegare44]

Can you provide a photo of the fuel pump capacitor ?

 

[Scoobyshep]

This is on a 004 (my 003 isn't close by and I'm not motivated enough to put pants on to go to it). However same fuel pump. See the metal tube bolted to the chassis? That's the cap.

Hope that helps

 

[rlegare44]

Thank you for the photo. I have no such wire like that on my machine. Sending you several shots of my pumps and connections. Are those little square boxes mounted to the pumps the capacitors?

 

[Scoobyshep]

Yes they are

 

[rlegare44]

Yes they are

I have two primary pumps, will I need to bypass each? I would of course do this only after I have run the wire from the + from the battery to the male quick connect for a first check.
If necessary, are these available for replacement?

 

[Scoobyshep]

If they are actually bad, yes both. Why are you running a wire from the battery to the pump? Didn't you verify power to the pump quick disconnect?

These are still available, but they can be quite costly. Not to mention the odds of all 3 failing together is slim.

 

[rlegare44]

The switch should only click once per position you move it to, from what you described with 24 volt to the pump qd and no noise indicates a pump problem.

A clogged pump may click very slowly. A gummed pump won't click at all.

What you are hearing with the clicks is the plunger inside slamming back and forth from spring pressure and electromagnetism.

Ok, to back up a bit. One rreply suggested I run a wire from + to the pump cap. My meter when reading battery V locked in at 24V. When I checked the quick disconnect plug the meter fluxuated all over the place way to high, but for a second it read 24V. I was going to try the wire to bat. + just to see if anything happened. If the pump is clogged, would that cause the emergency shut off breaker to kick out?

 

[Scoobyshep]

Ok, to back up a bit. One rreply suggested I run a wire from + to the pump cap. My meter when reading battery V locked in at 24V. When I checked the quick disconnect plug the meter fluxuated all over the place way to high, but for a second it read 24V. I was going to try the wire to bat. + just to see if anything happened. If the pump is clogged, would that cause the emergency shut off breaker to kick out?

I've never seen a pump clog cause the circuit breaker trip. That is a classic sign of capacitor failure.

Do this for me so I make sure that we're on the same page unplug the fuel pumps from the generator place the set in run and prime and two of those pumps should have 24 volts to chassis in the aux position all three should have 24 volts to chassis do you have these readings?


With the set in the aux fuel position plug in pumps one by one if the circuit breaker trips that pump needs service for sure

 

[Scoobyshep]

Also for reference I wouldn't run a wire directly from the battery to whatever you're testing because you're relying on absolutely no over current protection so if you have something badly shorted to ground you're going to find out very quickly and very burny. Just something to keep in mind