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Bad Bolt · 04-09-2018, 06:05 PM

Searched the web high and low and could not find anything on this code. Apparently, Cummins holds them from owner manuals, as they have EVERYTHING but the fault codes.

Mine starts, runs for a minute or two and quits. Oil and coolant is good and I get the following code.

blink blink blink

hit the stop button and get:

blink blink.....blink blink blink blink blink

Repeats...

What am I in for, here?

mackwrench · 04-09-2018, 06:16 PM

Code 25 is engine overspeed, I've heard fuel supply issue can set this code as the fuel pump governor holds the throttle wide open to maintain rpm, then once electric load is reduced, it can overspeed.

Have you tried to replace fuel filter?

Once it shuts down, can you it start right back up?

Can you see throttle solenoid linkage, all still hooked up and return springs?

Ilvmygt · 04-09-2018, 06:23 PM

This is what I found in my troubleshooting information.

Engine Above Speed Target Fault - Code No 25
(Governor unable to regulate to target speed)
Corrective Action: See an authorized Onan dealer

Would have to search the web to determine if it is a DYI repair.

NHRA225 · 04-09-2018, 06:37 PM

Post your Genny Model # and you'll get more Help !
IE: HDKAJ ??

Bad Bolt · 04-09-2018, 06:39 PM

It starts up every time after the fault kicks in, no problem.

This sucks!!

I guess this beast is coming out...

veraken · 04-10-2018, 06:26 AM

Go to the "More" section above, then "Files", then "Manuals". You will find the Onan Generator Service Manual. On page 18-14 your will find code 25 and corrective action. This should give you and idea of what's involved to correct this fault.

Bad Bolt · 04-10-2018, 09:32 AM

Quote:

Originally Posted by veraken

Go to the "More" section above, then "Files", then "Manuals". You will find the Onan Generator Service Manual. On page 18-14 your will find code 25 and corrective action. This should give you and idea of what's involved to correct this fault.

Thank you very much for that. A proper manual.

Sure wish I had a slide out for the generator.

I was looking at my coach and it looks like I may not have to cut any support framing to remove it. The front grill and access hood look to be removable where I could horizonally pull the unit out.

I'm wondering if that AC wiring bundle going in the front side is like a plug to be unscrewed and not hot hard wired all the way to the unit.

Anyone know???

I know there's the negative/positive wiring, the exhaust pipe, and fuel lines that need to be disconnected. Hope the generator chassis is not somehow bolted to the support frame. That would be a huge problem.

Papagoes · 04-10-2018, 10:55 AM

Had a 23 fault code a while back. Book said circuit board or coolant temp sender. Temp sender was the cheaper unit so I pulled the gen set from the coach. There are 4 3/8 bolts that secure generator to the framework. Two of the bolts broke because they were not anti-seized when originally installed. Had access to a small forklift to slide the generator onto, giving me a work platform. I believe the book says the generator weighs approximately 600 lbs. I did this myself in probably three hrs. but I am a big dude and enjoy working alone as to take my time and learn at my own pace. I suggest you get help to slide the unit out of the coach as it is a bit bulky. Try to use penatrating oil a few days in advance to loosen the threads on the mounting bolts. The front access door does come off but you might need help with that to keep from breaking the fiberglass door. BE CAREFULL NOT TO BREAK MOUNTING BOLTS. Other than that, a piece of cake and a great way to learn about your generator. Good luck!

MikeandJan · 04-10-2018, 04:04 PM

I had the same problem a few years ago. Generator (7.5 Onan Diesel) would start fine and then quit after about 1 minute, just when it should have picked up the load. Restart just fine and do the same thing. The generator was 12 years old at the time with about 1000 hours of usage. The problem was that it had thrown a magnet off the rotor which caused a fair amount of damage to the stator and cooling fan and it couldn't produce any current. The fuel control would call for more fuel to handle the expected load and overspeed causing the shutdown and overspeed code. With the cover off the genny, there were bits and pieces of magnet everywhere. The shop said they see one or two a year and that the magnets are bonded (glued) in and it just gives up. The repair was right at $3,500. I hope your problem is less.

Bad Bolt · 04-10-2018, 05:59 PM

Quote:

Originally Posted by MikeandJan

I had the same problem a few years ago. Generator (7.5 Onan Diesel) would start fine and then quit after about 1 minute, just when it should have picked up the load. Restart just fine and do the same thing. The generator was 12 years old at the time with about 1000 hours of usage. The problem was that it had thrown a magnet off the rotor which caused a fair amount of damage to the stator and cooling fan and it couldn't produce any current. The fuel control would call for more fuel to handle the expected load and overspeed causing the shutdown and overspeed code. With the cover off the genny, there were bits and pieces of magnet everywhere. The shop said they see one or two a year and that the magnets are bonded (glued) in and it just gives up. The repair was right at $3,500. I hope your problem is less.

I remember reading your story, now. Good Lord I sure hope this is not my reality....

MikeandJan · 04-11-2018, 07:17 AM

I forgot to mention trying to start/run the generator with the breaker in the off position. The shop that fixed mine said that would help determine if the problem was in the electrical control circuits or the generator engine. Initially they thought my problem was the controller, which is also expensive. Good luck

pumper9x9 · 04-11-2018, 07:23 AM

If it's just a sensor Great. But even if it's not and you have to pull the generator out of the coach replace ALL the sensors. They're cheap and they wear out. Otherwise somewhere down the road you'll have one go bad and have the cost or hassle of pulling the generator out again. Good Luck hope it's just a sensor.

Bad Bolt · 04-13-2018, 07:54 AM

If I end up pulling it out of the chassis, believe me, any and all maint items and sensors will be replaced.

One worry is the coolant temp sensor giving me trouble to remove. I've heard they are not easy to get out due to corrosion and weak sensor construction.

Any tips on what to replace are welcome!

Papagoes · 04-13-2018, 07:15 PM

If you destroy the thermostat housing trying to get the temp sender out, so be it. I doubt the thermostat housing is that expensive. And you might as well replace the thermostat itself while you are in there. BE SURE TO USE TEFLON TAPE OR TEFLON DOPE on the temp sender threads when you go back together with this. It will make it so much easier to work on if it has to be worked on again, plus it will seal the threads from leaking coolant if done properly.