7.5kw onan diesel generator issue

[Phaeton04]

Hi,
I have a 7.5kw HDKAJ diesel generator that will run for about 10-20 minutes (depending on outside temp) and then shut off. I replaced the temperature sender/sensor, thermostat and gasket Saturday 8/20/2022. Topped off the oil and coolant and started the generator and it still did the same thing. I also checked the extra fuel filter that tiffin installed on the 02 phaeton and someone has already removed that filter.
The coolant, oil and filter was changed last year in October. I used prestone 50/50 10 yr 300.000 mile mix and rotella t4 15w40 oil. I didn't record how many miles I had on the generator before I changed everything last year, but I would imagine I have maybe 50 - 100 hrs.
I don't know what else to do. Can someone please help with this issue..
Oh yeah, the code will flash 1 blink and when I press the stop/start button it will blink 3 times and pause and blink 3 times.
I dont know what else to do other than change the oil since its time to do so.

 

[Scooterfan]

Well, mine is a 5500 Onan Marquis...but I had the same issue. Upon the suggestion of someone (here I think) I purchased and installed a new fuel pump. Works flawlessly now. The premise is that the fuel pump may get hot and stop working. Not sure exactly why, but it's a cheap "try"...and easy installation. On a side note, if you do decide to replace the fuel pump, buy and install a fuel shutoff valve (if you don't already have one). On mine, when removing the fuel line from the filter and pump assembly, the fuel ran freely. With a shutoff valve, it's easy to swap out filters in the future. Blessings...oh and here's a link to a YouTube "how to" video:



Hmmm...it looks like a bit more complicated than mine was

 

[Phaeton04]

Thank you so much for the response. I will order the fuel pump.

 

[Rich W.]

Could also be the internal (fixed) fuel filter - it does sound like a fuel problem. Cheaper to buy a filter than a fuel pump and its a maintenance item anyway. So I’d try that first. Chances are a pump for a diesel genny is not as cheap as for a gas unit.

 

[Fish]

Reset the code and try again and see which error you get.

How to Read Onan Generator Fault Codes (Cummins Blink Code)

They use a blink and pause design to make their numbered codes clear and not confusing. Read our guide for examples and the full list with problem causes.

thecampingadvisor.com

 

[Phaeton04]

Hi Rich and Fish..
I reset the generator and started it up and it did the same thing.. it ran for about 15 minutes or so and shut off. It presented the same codes on the 7.5kw diesel genset.... the code will flash 1 blink and when I press the stop/start button it will blink 3 times and pause and blink 3 times and then a longer pause and then it will start over with the 3 blinks..
Rich, I will order and install the fuel filter from amazon since I cant find it locally..
I hope that helps.
Thanks

 

[Rich W.]

I had an 8kw Panda diesel genny on my sailboat and it was doing the same thing - fuel filter was it. Its also good to carry spares for it and the engine since one tank of bad fuel can leave you stranded.

 

[Phaeton04]

Thank you,
I received the fuel filter today from the post office. I will be installing it and will repost my results.

 

[Phaeton04]

Well everyone!!!! I replaced the fuel filter, changed the oil and filter, cleaned the spark arrestor, changed the thermostat and temp sensor/sender, made sure the temp sensor wire was tight and connected and topped off the coolant.

I started the generator and it ran for 12 minutes and shutdown.. Man, was I disappointed and frustrated. I even took the back panel off and inspected the water pump belt and it is not cracked and seems to be tight. I tried to turn the water pump pulley with my hands and I couldn't move it.
I did notice that when the generator shutdown the radiator pipe was very hot but the water inside the coolant reservoir was warm to the touch. Also, the water pipe that leads from the radiator cap the radiator was bent in two places. Could that have anything to do with it. I tried placing it so it would not be bent, but I have not started it back up.. I still have the back panel off, just incase I need to replace the water pump..

What could be causing it to still shutoff. Also, it flashes the same code as before...Code 33

Anyone have this problem or any suggestions.

 

[Fish]

Google is great, or Bing.

The fault code 33 indicates that the engine coolant temperature is higher than the design limit, in other words, it signals overheating conditions. There are several issues that can cause coolant temperature to exceed the safe limits, identifying the correct one is the main step to fixing it.

Fixing Onan Generator Fault Code 33 (What Does It Mean?)

This code seems to be missing from the manual as well. The reason for that omission is that the problem is an uncontrolled shutdown due to overheating.

thecampingadvisor.com

Also another article on code 33 and making sure you're reading the fault codes correctly.

Hope this helps.

 

[Phaeton04]

Thank you.
I read the article you sent me and followed the instructions given and Still it shutdown.. The only thing I have not done so far is replace the water pump...

 

[Voyageurs]

Well, we had that issue, but for us it was the temp sensor. That’s the little brass thingy mounted in the head. Is that what you changed?

 

[Phaeton04]

Hi Voyageurs.. Yes, that is what I changed, along with the thermostat.

 

[Voyageurs]

Hi Voyageurs.. Yes, that is what I changed, along with the thermostat.

Yah. That’s what those symptoms were for us. Hmmm. We knew a guy that had something similar although symptoms were slightly different. He did a coolant flush. Something about the spot where the sensor head was crusted over. Not the sensor itself. I can’t remember the details. But a coolant flush was the answer.

I’m afraid I’m not much help. Good luck and let us know.

 

[Phaeton04]

okay, I will flush it out tomorrow and let you know my results.
Thanks

 

[Phaeton04]

Hello Everyone,
I reflushed the radiator and noticed the radiator cap seal was split and in bad condition.. I purchased a new cap and added new coolant at the rate of 60% coolant to 40% water. Started the generator and it ran for 1 hour and 45 mins, so I shut it down. I pray that this solved the problem..
I have a trip planned for next weekend {labor day weekend} so I will post my results then.
I thank everyone for there input..

 

[Voyageurs]

Hello Everyone,
I reflushed the radiator and noticed the radiator cap seal was split and in bad condition.. I purchased a new cap and added new coolant at the rate of 60% coolant to 40% water. Started the generator and it ran for 1 hour and 45 mins, so I shut it down. I pray that this solved the problem..
I have a trip planned for next weekend {labor day weekend} so I will post my results then.
I thank everyone for there input..

Good to hear. Hope that has got it.

 

[Phaeton04]

Well everyone,
I went on my trip and the old generator did not last the whole trip. It only ran for about 30-40 minutes. The outside temp was about 99 degrees.
Im about to give up on fixing it..

 

[Kuate]

Did you ever get it fixed? if so, what was it?

 

[Madtaxi]

I had the same engine shutoff issue with error 33. I dropped my generator and replaced the temperature probe, thermostat, glow plugs, and flushed the radiator several times. After reinstalling the generator, I still had the same shutoff with code 33... Finally, I tried installing a new fuel pump and that solved my issue. If you haven't yet, try replacing your fuel pump & filter. Best of luck!