MEP-016B Tripping DC Control Circuit Breaker

[Redah]

MEP-016B Tripping DC Control Circuit Breaker

Hello Everyone,

I’m having a problem with the ‘DC Control Circuit Breaker’ tripping on a MEP-016B with 1824 Hrs.

Got this little monster a month ago. Flushed fuel lines and tank, replaced fuel filter, refilled with fresh fuel and put in 2 new 12V batteries (in series).
It started and ran it for about 30 minutes then I shut it down.
A week later, I tried to start it again, but as soon as I turn the ‘Master Switch’ and reach ‘Run Aux Fuel’ it trips the ‘DC Control Circuit Breaker’.
If I disconnect the ‘Fuel level Switch’ on the Fuel Tank, turn the ‘Master Switch’ to Start, it will turn over, it wont trip the ‘DC Control Circuit Breaker’ but it will not run. Same will happen if I re-connect the ‘Fuel level Switch’, then disconnect the wire #11 on the back of the ‘Master Switch’, or 1 of the top 2 wires on the back of the ‘DC Control Circuit Breaker’.

Please see attached photos, and see if you can help me out using the photos as a guide.

Thank you all in advance.

 

[Suprman]

Disconnect the electric fuel pump power wire and try.

 

[Redah]

Suprman,

Would you kindly using the 4th photo, guide me to which power wire you are referring to.

 

[Suprman]

Photo 5 blue arrow shielded wire power to electric fuel pump. I have had those pumps short out on me a few times.

 

[Redah]

Photo 5 blue arrow shielded wire power to electric fuel pump. I have had those pumps short out on me a few times.

Much Obliged Suprman,

I will try it tomorrow and update.

 

[Speddmon]

Try what suprman suggested.

I don't have any experience with the 016 series generators, but they have the same style fuel pumps as the 002 and 003's from the looks of your pictures. If there is more than one pump, disconnect them one at a time until you find the one tripping your breaker. Once you have found it, cut out the surge suppressor that is in the power line to the pump and tie the wires back together (picture #5, the blue arrow is pointing to the suppressor).

Typically the pumps are still good, but the capacitor in the suppressor shorts and causes the breaker to pop. Remove the capacitor and all is good again.

 

[Redah]

Thank you Speddmon for answering my message.
Later today, I'll be following the suggestion that Suprman's and You recommended.
I'll report back with results.

 

[Redah]

Disconnected electric fuel pump power wire (blue arrow, photo #5 above). Still the same.

Disconnected electric connector on Solenoid (red arrow, photo #6&7 below). Same result.

 

[Redah]

I went back to wire #11 on the back of ‘Master Switch’ (photo #3) and ‘Fuel Level Switch’ (photo #4). Disconnecting one or the other resulted: No tripping, but no start.
I traced wire #11 to the ‘Fuel Level Switch’ and snipped it. I know can turn the ‘Master Switch’ to pass ‘Run Aux Fuel’ without tripping the ‘DC Control Circuit Breaker’. I will have to wait till my neighbors wake up to nurse their Hangover before I'll attempt to fire it up.

 

[Redah]

I just tried to start it, but it won't unless I push the 'Governor Linkage' in, and maintain it pushed. When I let go off of it died. It also tripped the breaker. Now with the wire I snipped earlier still unconnected, the circuit breaker trips when I move 'Master Switch' to 'Run Aux Fuel'.

Did I do something wrong by forcing the Governor?

Just in case I over heated some connection, I'll let it rest for an hour or so to cool of and try again to see what it does.

 

[Redah]

Back where it was before, plus, now it's tripping breaker even with 1 of the 5 wires on the 'Fuel Level Switch' disconnected, the same wire that cured the tripping problem before

 

[Redah]

Any suggestions?

 

[DieselAddict]

I hate to say this but it sounds like you could have a wire where the insulation has rubbed through and its grounding out.

The only real advice I have right now is to start going through the wiring with the diagram and look for shorts to ground with an ohmmeter.

Start at the START/RUN switch and lift each circuit going out and check for low resistance paths to ground.

 

[Redah]

Thank you DieselAddict.

I will follow your suggestion and report back, it may take me a while, as I just started another project (Cargo Trailer Conversion).

I will keep monitoring the topic.

 

[87Nassaublue]

Hi Redah,

I have a 016B that I just resolved many issues, one of which was the same as your's. The low fuel float switch was causing my circuit breaker to trip. I also had problems with the fuel cut off solenoid not pulling in and allowing the governor to work. After reverse engineering schematics from training courses, I was able to figure out I had some issues on the circuit board that is to the left of the control panel. There are relays K1 through K4 on that board that have different tasks. One operates the fuel cutoff soleniod and another is the low fuel shut down.

After much troubleshooting and head scratching, I tracked the problem down to something on the circuit board. I was able to unbolt the circuit board and lay it over with the wiring harness still connected. I found that there were two sections related to the relays that had over heated and de-soldered themselves causing cold solder joints and intermittent connections. I fired up my soldering iron, re-soldered the connections and those problems were resolved. I would suggest getting this circuit board un-bolted from the frame and inspect the back for overheated and/or cold solder joints.

The circuit diagram for this board does not seem to have ever been published and it's probably why everyone seemed to shy away from this unit. Once you figure it out, it doesn't seem so difficult.

 

[Redah]

Thank you 87Nassaublue.