Onan genset keeps stopping fault code 13

[harvey hellman]

We have a onan genset MDKAW 9.5 kva unit.
After about 15 seconds of running it turns off with fault 13.
It is a low voltage read fault.
We just replaced the ecu $1500 and the fuel pump.
The engine side runs fine so we think its the power generation side?
Anyone had this issue that may be able to advise a fix?
It is in Indonesia so calling the Onan service tech is not really an option.

[GordMay]

“... UNDERVOLTAGE FAULT—CODE NO. 13 (Controller unable to maintain rated voltage)
Corrective Action:
Reduce the number of connected appliances, especially when air conditioners and battery chargers are running ...”

➥ https://manuals.heartlandowners.org/...ng%20Codes.pdf

[Fuss]

Originally Posted by harvey hellman

We have a onan genset MDKAW 9.5 kva unit.
After about 15 seconds of running it turns off with fault 13.
It is a low voltage read fault.
We just replaced the ecu $1500 and the fuel pump.
The engine side runs fine so we think its the power generation side?
Anyone had this issue that may be able to advise a fix?
It is in Indonesia so calling the Onan service tech is not really an option.

Maybe the error 13 is just because the engine slowed and has nothing to do with the generator unit.


Does it stop suddenly or over 3 seconds first slowing a bit.
if first slowing a bit then it might be fuel. maybe a filter or blocked line.
I am sure a good generator diesel mechanic can solve it better than asking on here.
We don't have enough info and will spend Ages asking you lots of questions.
Maybe try replacing all filters and then running from a liter of diesel feeding the fuel pump with a new 20cm long pipe.


Try switching the main breaker off on the generator and running it.

[harvey hellman]

All power appliances are disconnected so no power draw from the unit,
New fuel filters, new fuel pump,fuel flow perfect.
The fault is in the power generating half of the genset.
I wish a service tech could fix it but they dont really exist in the remote 3rd world tropics where we are. These things only fail when you are no where near a service centre

[harvey hellman]

Originally Posted by Fuss

Maybe the error 13 is just because the engine slowed and has nothing to do with the generator unit.


Does it stop suddenly or over 3 seconds first slowing a bit.
if first slowing a bit then it might be fuel. maybe a filter or blocked line.
I am sure a good generator diesel mechanic can solve it better than asking on here.
We don't have enough info and will spend Ages asking you lots of questions.
Maybe try replacing all filters and then running from a liter of diesel feeding the fuel pump with a new 20cm long pipe.


Try switching the main breaker off on the generator and running it.

Main breaker off, fuel filters and pump replaced, fuel run from container with hose all works fine,the engine runs great for about 10-20 seconds and then the ecu turns it off suddenly.
Replaced with new ecu as we thought it was faulty but still shuts down due to low voltage.
Start battery is new too.
Seems it must be on the power generating side?

[Captain Bill]

I have a 5kw mdkau so my experience may not directly apply. If the ECU does not see 120v +- in about 15 seconds it shuts the engine down. The generator applies a small voltage to the coils to start building the magnetic field and this builds to 120v pretty quickly. All of this goes through the brushes on the rotor. If the brushes are bad then the magnetic field cannot be established in the coils and 120v will not be generated. Brushes wear out and sometimes damage the contact rings when they do. I got 2300 hours on my first set of brushes but only 1050 on my second set because there was a small area on the contact ring that abraded the graphite brush. I replaced then replaced both pieces.

The circuit applying and controlling this voltage is called the field flash circuit and the only moving parts (hence likeliest to fail) are the contactor rings and the brushes. I would look at the brushes first. Since you have already replaced the ECU where all of the electronics are located you have likely eliminated that as a problem. The remaining parts are voltage sensing coils which are a serious problem because they are embedded in the coils of the generator.

Like I said this information is for a 5kw mdkau and may not apply to your genset.

[Kita]

Ya know,an old salor once said sailing is about fixing your stuff with having to make due with whatever you have in exotic locations. well it sounds like you've succeeded. Sorry I can't help.

[SeeMonstrEd]

also check for loose connections and broken wires. I ended up rewiring my entire genset because the plastic POS junction for the control wires had so many bad connection. It was mounted on the case the vibrations just killed it. I replaced it and all the wires then relocated it on a bulkhead.

Capt Ed

[sailcrazy]

We have an Onan genset, 6/5kva, and have had similar problems. We put a digital voltmeter+ freq meter on the output, and discovered the genset governor had gotten out of adjustment. I loosened both the over and underspeed set screws(bolt heads), and reset the eng speed so it was putting out the required voltage(230v) and 50Hz required for our system. Of course it slowed a bit when under heavy load, so I reset the governor to be a little over a no load and a little under at heavy load....and then reset the over and under set screws(bolts). I checked the wires to the control transformer in the control box before I ever started, so I knew they were on the correct taps, to ensure they were solidly in place. Worked for us!

[Squanderbucks]

I second those comments by Captain Bill. I have a Generac 8KW that had similar but not exactly the same problem a couple of years ago. Part of my solution was adding an accessory part called a Field Boost Kit that made sure 12volts was fed directly to the generator field and brushes. Without it it was very erratic and difficult to start.
also depending on the hours on the genset - as he said if the problem is in the filed windings then that means a whole now generator portion of the genset will need replacing as parts are not available for just that..

[Diesel Bill]

Originally Posted by Squanderbucks

I second those comments by Captain Bill. I have a Generac 8KW that had similar but not exactly the same problem a couple of years ago. Part of my solution was adding an accessory part called a Field Boost Kit that made sure 12volts was fed directly to the generator field and brushes. Without it it was very erratic and difficult to start.
also depending on the hours on the genset - as he said if the problem is in the filed windings then that means a whole now generator portion of the genset will need replacing as parts are not available for just that..

Have to also agree. I have a 7.5 KW Onan on the boat (runs good) I bought a used Kabota GL 6.5 KW for the house. When starting the Kabota it would run fine for 10-15 seconds and then shut down. Turned out to be a defective voltage regulator. I found one on E-Bay for about $65.00 and that fixed the problem. Apparently the ECM senses low voltage and goes into a shut down mode. You can apply a low voltage to the exciter ring brush leads and bypass the regulator to test if it makes power. I did and got to careless and got hit with 240 VAC. Ouch! Be carefull if you try this and have someone there to do CPR. Hope it works out for you.

[Emerald Sea]

Harvey. Have you got to the bottom of this? What was the problem amd how did you fix it?
Thanks, Steve

[harvey hellman]

Still trying, ecu replaced but was not the issue, it is in the coil area and a work in progress

[tanglewood]

Have you been able to put a meter on the AC output to see what it actually measures, both in voltage and frequency?

Is this a 230V 50hz unit? 120/240V 60hz split phase? 120V 60hz?

[Royal Virgos]

I just had a brand new Onan installed and after 20 hours having a similar problem but it runs for 45 minutes and then dies. The Cummins tech has replaced the fuel pump so far and still working. I did see online error code 13 as being fuel related. The person that installed it suggested isolating the generator by using an external fuel supply and then work back.