MEP-831a will not start.

[indy76]

My 2 MEP831a's arrived the other day. One is a 2005 with 30 hours on it. I blew out the fuel lines and some horrific fluid came out. I changed the fluids and filters and added fuel and fired right up. Runs fine and produces power as it should.
Now for the 2nd unit. It's a 2001 with 1100 hours. I hooked up the batteries tried the switch and nothing. The unit is pretty clean and everything appears connected as it should. I folded down the gauge and switch panel and everything is connected and looks clean. Looking for a starting point to check. The pre heater switch does not make any sounds when I flip it like my running one. Nor does the fuel pump turn on when I flip the switch to run. Thanks for you help.

 

[uniquify]

Sounds like an electrical problem. Start with the easy stuff:
One 12v battery isn't enough by itself. Assuming you're using a pair of 12v batteries in series, are they both charged?
Are all battery cables getting a good connection.
Make sure the big red emergency stop switch pulled out.
Make sure the DC circuit breaker pushed in.

Both fuel pumps could be bad. Do the panel lights work?

Start small and work forward. You can do this.

 

[Zman498]

My mep831a has a similar problem, the main fuel pump is not pumping or making the humming ticking sound its suppose to. Switch it out with a brand new one and nothing. I curious if anyone know what component I can check or what component is responsible for starting up the fuel pump. Notes: Aux fuel pump works, continuity from battery to jack and plug on main fuel pump, batteries fine relays fine, no fuel in it.

 

[DieselAddict]

Hate to sound like a broken record but you need to start with the manuals. You can download them from the forum. There is a link at the top of the page for "Technical Manuals" aka TMs.

Go through the wiring on the machine and look for anything loose or disconnected. Check EVERY WIRE. I'm not kidding here - EVERY WIRE on EVERY TERMINAL. I'm repairing one now that needs an expensive component replaced because someone didn't check the wires and almost set it on fire.

Test the low fuel switch in the tank. The manual has troubleshooting info to test that circuit as well as all the circuits on the unit.

Until you look at the machine enough to be able to understand instructions like - Check the wiring on the COIL side of K1 since the power for the fuel pump routes through there - Its a lot harder for us to help you.

 

[Zman498]

Hey, good advice DieselAddict. So I went to the wire diagram and traced the circuit for the fuel pump (E2), made sure there was continuity all the way through, and checked if it was receiving DC volts, it wasn’t getting any volts. Also when the gen was on run on the START/RUN switch and circuit breaker in and E-stop pulled out, the fan inside the power converter (A-8(eight)) was not turning on. I stopped here, wondering if the power converter is bad now or if it could be a wire issue. I don’t think the relays are causing any of this, but still haven’t check them. Just letting you know where I’m at and if you know anything similar from experience let me know, thanks y’all.

 

[kloppk]

+24 volts takes a long path thru multiple wires to get to S1-5.
You ought to trace the power path from the battery's positive terminal thru all the points along it's path to S1-5.
Here are the step by step points that it get there from the battery's positive terminal

Battery + goes to Starter L4 (Big Stud)
Starter L4 (Big Stud) goes to Slave Receptacle Positive (Center Contact)
Slave Recepticle Positive (Center Contact) goes to K2-A1
K2-A1 goes to K13-A1
K13-A1 goes to P7-17
P7-17 goes to J7-17
J7-17 goes to TB5-13B
TB5-13B goes to TB5-13A
TB5-13A goes to CB-1 Line Side
CB-1 Line Side goes to CB1-Load Side
CB-1 Load Side goes to S19-A1 (Emergency Off Button)
S19-A1 (Emergency Off Button) goes to S19-A2 (Emergency Off Button)
S19-A2 (Emergency Off Button) goes to S1-5

Use your meter and check all the points along the path above, except the J7/P7 points and see if you have ~+24 volts at each point.
I suspect you will find power is not making it all the way the S1-5.

 

[Zman498]

So figured out the problem, just want to update you guys on what i found. So i went through the whole circuit for the fuel pump, testing every point with my volt meter and ended up finding nothing which was discouraging. But I was troubleshooting again on it last week and was looking at the direction of the diodes everyone, and ended up finding that the CR2 or CR3 was facing the wrong way, which was pretty crazy, I turned that diode around and started it up, did a load test, everything is fine on it know.
But i have another issue if you guys can help me on it I'd really appreciate it. So my other MEP-831A 3KW has a problem turning off. I adjusted every little spring and part right next the the electric actuator, including the magnet. It still wont shut off. Someone told my that the Masterswitch could be bad. What is happening is that, I turn on the genset and the throttle goes up high like full throttle and the genset is running like at full speed. Then i try to shut down the genset with the Masterswitch but it des not shut off, so i tried to shut it off with the Emergency switch but it still doesnt shut off so I end up shutting it down the the little lever on top of the Genset I think its called the choke idk. I appreciate any feedback guys, Thanks again.

 

[DieselAddict]

You need to troubleshoot the governor module.

 

[kloppk]

Suggestion..
Disconnect the white connector in the two wires going to the actuator on the engine.
Lift the actuator off the magnet. Pull start the engine using the compression relief. The engine should run at a relatively low RPM. If it's running at a high RPM then there is an issue with the mechanical governor either on the outside of the engine or inside the crankcase.

 

[kloppk]

Also try reconnecting the white plug in the wires to the actuator. Then start it normally. When running the LED in the righthand relay in the control cube should be illuminated. Then move the master switch S1 to OFF. The LED in the right hand relay should go out. Does it?

 

[Guyfang]

Before knob dicking everything, you should have asked these questions. Now you have to consider whether you have to go through the TM and readjust the mechanical Gov, before trying to find out if the problem is electrical.

 

[CallMeColt]

I just got mine going a few months ago & I did a lot of troubleshooting like you have. Annoying but at the same time, you learn a lot about the function of the machine. I still have some minor kinks to work out but it runs like a champ now. I posted some videos on the unit while I was troubleshooting. Here is the link to my thread here on the forum that has a lot of good information in it along with some videos I made;
https://www.steelsoldiers.com/showthread.php?190228-MEP-831A-Fix-up-Thread

 

[sdsuguz]

So figured out the problem, just want to update you guys on what i found. So i went through the whole circuit for the fuel pump, testing every point with my volt meter and ended up finding nothing which was discouraging. But I was troubleshooting again on it last week and was looking at the direction of the diodes everyone, and ended up finding that the CR2 or CR3 was facing the wrong way, which was pretty crazy, I turned that diode around and started it up, did a load test, everything is fine on it know.
But i have another issue if you guys can help me on it I'd really appreciate it. So my other MEP-831A 3KW has a problem turning off. I adjusted every little spring and part right next the the electric actuator, including the magnet. It still wont shut off. Someone told my that the Masterswitch could be bad. What is happening is that, I turn on the genset and the throttle goes up high like full throttle and the genset is running like at full speed. Then i try to shut down the genset with the Masterswitch but it des not shut off, so i tried to shut it off with the Emergency switch but it still doesnt shut off so I end up shutting it down the the little lever on top of the Genset I think its called the choke idk. I appreciate any feedback guys, Thanks again.

Hi, thanks for posting this and I believe I’m having the same issue. Is there anyway you can pass on which direction the diodes should be?

 

[kloppk]

 

[sdsuguz]

Kloppk! Cannot thank you enough. I have no idea where you pulled that diagram but it’s certainly not in the 3 known pubs I’ve downloaded. Where did you get that?
Thanks again and this should solve my immediate problem.

 

[kloppk]

Where did you get that?

It's at the back of TM 9-6115-639-13&P

 

[Guyfang]

What 3 TM's did you use?