Onan Generator Dies When Engine Started - Code 27

[wraanderson]

I would like to revive this isssue once more in case my experience can help others with this problem. We have a 2006 Alpine 36 FDDS with a 7.5 kW Onan generator.

I had been having both of the following problems as discussed in past threads:

1. When I would start the Onan generator, it would run perfectly for about 30 seconds until the relay clicked in, then it would die and would be very difficult to get running again.

2. If the generator was running and I started the engine, the generator would stop running.

I lived with this for several years and attempted some work arounds as suggested in previous posts, but it was always a pain.

Finally after researching way back in the archives I found a post about a fix that originally came from Western RV. It involves adding 2 additional relays to the system. This came from a post by "midflajim" in August of 2008. I contacted Jim and he sent me a wiring diagram showing the addition of the relays (thanks Jim if you are reading this).

I recently had a local service company install the relays and so far it seems to have solved all the problems. Quite a relief. I have not had the coach out on an trip since then to give it a thorough testing, but in trying different combinations here everything seems to be good.

I am posting this because this fix has not been discussed for quite some time and there has been a lot of discussion on other causes and solutions since then. I was afraid that this final fix for these problems may have gotten lost in the process.

The work I had done cost $556, but there was some added research and diagnosis that was done, so just the install of the relays should be less.

I have the wiring diagram and would be happy to email it to anyone that is interested, or if someone would like to post it somewhere where everyone can get to it that would be great.

[Birddog Pilot]

I had the same problem that no service facility was able to resolve. As you described, as soon as the relay would activate the generator would die. No, I did not add any relays, but many other fixes were tried including replacing the generator’s “brain box.” The only way the generator would continue running was to put some sort of AC load on it; often just having several of the DC light switches pre-set to “on” was enough to create a load that would keep generator running. Without a load pre-set, the generator would always shutdown with the 27 Error Code. I continued to use this work-around method for a year or so and the generator would operate properly. I found that if further starts were necessary they too were successful. All this was 3-4 years ago when I had all but given up and resigned myself to the fact that the problem would never be resolved. While having routine maintenance done with Guaranty in Junction City, OR I squawked the problem again. What finally resolved the problem was a simple computer update that they performed from a laptop, and the generator has functioned absolutely perfectly ever since. I can’t tell you the type or version of the update, but perhaps if anyone else is experiencing a similar problem, Guaranty may be able to either resolve your issue or forward the information to your maintenance facility.

[Midniteoyl]

Sound like the changed the drop-out voltage..

Researching this, it appears to be a low voltage problem.. But that could be from just about anything from the brushes, to the volt regulator, to the stator.. Seems like your service tech simply adjusted yours to work.

[Old Scout]

The number 2 problem you described is well-known but not well understood. My initial efforts to resolve this problem with Xantrex and Onan resulted in an "ethnic stand-off"--neither would take ownership for the problem or the fix. Not sure how the relays or new programming would work but the previous work-around is to manually shut-off the xantrex charger which basically by-passes the issue when you start/run the Cummins--no cost! Not sure what your number 1 problem is about--your description suggests that the Onan would quit after 30 seconds of running everytime you try to use it--is this correct????? I had this problem early on when the coach was new and it turned out to be a dead cell in one of the house batteries.

Can you post the new relay wiring diagram--curious minds will want to know?????

[EngineerMike]

If you email me the schematic to TechLib at AlpineCoach dot org, I'll post it on the ACA Tech Library and here as well.

[Birddog Pilot]

Midniteoyl, possibly so, but this particular generator had been worked on by several shops including one that specialized in Onan generators with absolutely no solution to the start-stopping problem. And, yes, adjustments were made, components were tried and or replaced, the and the main board was changed; and when that didn’t work the old one was reinstalled.

All I know is that I was standing there while the laptop at Guaranty was being used to do its “Magic” and after the update or whatever it did, the Onan worked perfectly and has been doing so for the last 3-4 years. Being one that does not knock success, I really don't care how they resolved the problem; the main thing is the Onan now operates properly.

[Midniteoyl]

Originally Posted by Birddog Pilot

Midniteoyl, possibly so, but this particular generator had been worked on by several shops including one that specialized in Onan generators with absolutely no solution to the start-stopping problem. And, yes, adjustments were made, components were tried and or replaced, the and the main board was changed; and when that didn’t work the old one was reinstalled.

All I know is that I was standing there while the laptop at Guaranty was being used to do its “Magic” and after the update or whatever it did, the Onan worked perfectly and has been doing so for the last 3-4 years. Being one that does not knock success, I really don't care how they resolved the problem; the main thing is the Onan now operates properly.

[EngineerMike]

As promised, here is the relay schematic referenced above:

[M&J]

I have experienced this problem but i have realized that when I have had the problem it was due to settings on the silverleaf.

I store my coach in my shop so I disable the exerciser and auto charger so the generator does not start while in the building.

If I forget to enable the exerciser and the auto charger the generator will act exactly as you have described.

A month or so ago while Elk Hunting and dry camping our generator did this and I realized I had not enabled the exerciser and auto charger so via the silverleaf I activated both. This was a few days into the trip and late in the day when I got to camp. The generator still had the issue and the batteries were low. I disconnected both the chassis batteries and the coach batteries. When I reconnected them the generator started immediately and ran perfectly for the next 5 days.

I met Birddog pilot at Cummins NW this last summer when I had issues with my generator after having it serviced. Fuel delivery problem that was corrected. Hope all is well with you.

I hope this info helps.

Merry Christmas to everyone!