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Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15191
Experience:  Certified on Onan and Generac generators
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Onan diesel generator 2007..600 hours..been in storage for

Customer Question

Onan diesel generator 2007..600 hours..been in storage for a while..was running fine most of today..shut off..sevice light is blinking 3 times..will start but then runs a low rpm..kind of ruff then shuts off after a few minutes?
Submitted: 2 years ago.
Category: Small Engine
Expert:  Hank F. replied 2 years ago.
My name is ***** ***** I am going to assist you with this.
It sounds like you are having fuel issues.
What is the model number of the genset?
When it was in storage, how long is "a while"?
Customer: replied 2 years ago.
See attached make model #
Customer: replied 2 years ago.
Update..I started up today ran for like 15 to minutes perfect..smooth no smoke...under load of all 3 ac hits...after the 20 minutes started running rough turned off ac units so it would not shut down
Customer: replied 2 years ago.
Sat for about 6 months will minimal time on generator
Expert:  Hank F. replied 2 years ago.
OH, yeah. I am intimately familiar with the HDKCA units.
As you've noted, coded 3 is merely a service indicator. Lets go in and see what actual fault code is there.
Go to the genset and use the switch on the set itself.
Press 'Stop' 3 times within 5 seconds. The light in the switch will start flashing.
If the light flashes 3 times, pauses for 3 seconds, and flashes 3 more times, press and immediately release 'Stop' one more time.
This will put the controller into Fault Read Mode.
The light will flash (X) number of times, pause for 1 second, and flash for (X) number of times again. Count the flashes before and after the pause.
This will be the Fault Code.
Example: 2 rapid flashes, 1 second pause, 5 rapid flashes is a Fault Code 25.
There may be more than one Fault Code stored, so watch the light very carefully. If there is more than one code, it will display them all in order, and then start over again.
Be very careful not to misread a first level fault code (single digit code) as a second level fault code (double digit code).
The way to tell the difference is by the length of the pauses.
There is a 1 second pause between digits of a second level code, and a 3 second pause between codes.
For example, if it is flashing 2 times, 1 second pause, flashing 2 times, 3 second pause and repeating, then this is a second level fault code of 22.
If it is flashing 2 times, 3 second pause, flashing 2 times, 3 second pause and repeating, then this is a first level fault code of 2.
What Fault Code are you getting?
If it is too confusing, I have made a short video demonstrating the procedure.
Copy and paste this link to see it if you need to.
Customer: replied 2 years ago.
Initial blink was 1 blink...I think IT was 5 blinks after..I looked up code last night and it said high temp..I checked coolant reservoir was low/empty..filled it up and it did not shut off just ran really roughStarted up this am ran great for 20 minutes then started acting up.. After it rancor a while reservoir was still full
Customer: replied 2 years ago.
Ran for a while
Expert:  Hank F. replied 2 years ago.
So it is giving you a code 15 right now?
This is still sounding like a fuel issue.
What you really need to do first is to get some fresh fuel, and add some type of treatment to it, and run it through the genset.
You don't necessarily have to fill your coach. What I would do, if you have the means, is to just get a 5 gallon can of diesel, treat it with a quality fuel cleaner such as Sea Foam, and run it through the genset. You would need to remove the existing fuel supply line from the genset, and get a piece of fuel hose to run from the genset directly into the gas can. The pump in the genset is plenty strong to pull the fuel out of the can.
Let me know if that does not take care of it.
Customer: replied 2 years ago.
Wow..just saw your video...thought I burned it up..ha...what fuel cleaner do you recommend?
Customer: replied 2 years ago.
Another note..right after I filled the coach up is when it happened..not sure how long the diesel sat in it before filling it up
Customer: replied 2 years ago.
Curious why it would start running great and fuel problem would show up after 20 minutes of running
Expert:  Hank F. replied 2 years ago.
The fuel treatment I would recommend is Sea Foam. It is available at most any auto parts store.
There are some strange things that happen with these units. Topping off the tank may have stirred up some contaminates that were in the tank - it is hard to say.
Expert:  Hank F. replied 2 years ago.
Have you been able to run the fuel treatment through it yet?
Did it help?
Customer: replied 2 years ago.
Yes, I ran sea foam through the RV now...changed fuel pump, fuel filter, oil filter and air is sporadic when it acts up..I blew lines with air house thinking some debris was in it...funny how it happened when I was filling up with diesel..Out of ideas..just through a 15 code
Customer: replied 2 years ago.
Could being low on coolant cause it?
Customer: replied 2 years ago.
Another does not run at high idle when you first start it up..does not sound like it anyway
Expert:  Hank F. replied 2 years ago.
Low coolant will not cause a code 15.
Code 15 is Under Frequency - it means that the generator is running too slow.
You should not have blown air through the fuel lines. Some of them have a check valve in them, and blowing air can blow out the check valves.
Lets do a fuel flow test, and make sure it is flowing plenty of fuel.
To do a fuel flow test, get underneath the genset, and remove the return fuel line. It is marked on the side of the genset.
Attach a piece of fuel hose to the nipple, and run the hose into an empty container of at least 1 quart capacity.
Press and hold the STOP/PRIME button for exactly 1 minute.
In 1 minute, it should pump a minimum of ½ pint of fuel. If it does not, there is an issue with the pump or the supply lines.
Customer: replied 2 years ago.
is that near / under the fuel pump?
Expert:  Hank F. replied 2 years ago.
No, it is outside the genset, where the fuel lines attach to it.
Customer: replied 2 years ago.
Will do the test you said this evening..we have a 2007 monaco dynasty just above the fuel line that goes to the generator (sits in one of the bay doors) I see a fuel filter above the gas tank, passenger side mounted to the body (looks similar to an oil filter), do do you know if this fuel filter is in line with the generator...just curious if you think I should try and change it..thanksFunny thing is it seems to run fine while coach is running hard hard on highway, when pull over and stop with load on it is when AC's will cut off..twice night we have gotten back up in highway and will maintain..might be a coincidence but thought I would mention
Customer: replied 2 years ago.
Both times ac has cut out is when we are at idle or lower speeds.. When back up on highway..all good
Expert:  Hank F. replied 2 years ago.
There should not be a fuel filter in line like that, but it is possible someone put one in there. You would need to trace the lines to see for sure.
What you are seeing is really strange. Motion should have no effect on the voltage output at all. If the genset quits producing power, it will shut down, so it is doubtful that the genset is what is causing that. You may have a loose wiring connection somewhere in your coach.