6.7L MegaCab

Well, one thing after another. The trailer was at the shop for a couple months after our trip to NM because the wind caught the awning and flipped it on top of the roof before I could roll it up, ruining the awning, cracked the rear fiberglass cap, bent the luggage rack, cracked the AC shroud. All is fixed and we were finally able to take it out last weekend. I should have checked the generator before we left (probably best that I didn't as we may not have left), but I had no reason to believe anything was wrong as it worked flawlessly to and from NM and high up in the Colorado mountains.

The generator will start then shutoff after a couple seconds or simply won't start. The codes alternate between 36 and 37. When I disconnected the 50 amp cord from the generator, it ran for a minute or two then shutoff (just that one time). Now it doesn't matter if the cord is plugged in or not. Any idea what may have caused this issue? The trailer was in the shop from around mid July until beginning of October because of backordered parts (ladder - insurance company wanted it replaced for reasons unknown to me).

Model number: 5.5HGJAB-1038D Spec: D

Despite the generator we still had a great time and the Trojan batteries worked flawlessly running the heater keeping the kids warm.

First night was up near Mammoth Designated Dispersed Camping Area, Utah.

1-2-3

You might ask this question on the forum at smokestak dot com. For some reason, besides old tractors and engines, they have some guys on there that know more about these things than anyone I've ever seen or heard of. Some of them are into collecting and restoring these generators.

6.7L MegaCab

This will always be my first stop. You will be amazed by the vast amount of knowledge on DTR. Thank you for the link I will check them out.

j_martin

I would guess that there's a fuel problem, either fuel pump, plugged filter, suction leak, etc. Is there a chance that vandals put some water (or worse) in the fuel tank? (BTDT, got the T shirt)

Makes sense that it'd run longer with the power cord disconnected. It uses less fuel with no load.

KATOOM

Sounds like either a fuel pump, fuel level in the tank, or potentially oil level sensor. Make sure there's ample fuel in the tank since those fuel level gauges are usually pretty inaccurate from the RV manufacture. Then hold the generator start button in the "prime" position and listen for the fuel pump. If you cant hear it then its probably not working. Not uncommon. If the fuel pumps working then check the oil level and make sure its up to the top. Also, checking all electrical connectors are fully plugged in and not rubbing any wires. Lastly, if your gen is carbureted then make sure the altitude adjuster is in the correct setting.

If you still cant figure it out then try rv.net forum. Lots of people over there know about these generators.

6.7L MegaCab

Thanks all for the responses. The fuel pump is working. I don't think the fuel was vandalized as I used the same fuel to refill both my boys' dirt bikes.

I didn't have time to troubleshoot any further before I had to take it back to the storage lot before the HOA started complaining. I noticed a fuel filter right by the tanks so I will replace that filter as well as the Onan filter and see if that changes anything. I think with priming it, the fuel pump is pulling enough fuel and once it starts, I believe the logic is for the pump to turn off and it runs from siphoning the fuel, but if either of those filters are plugged, that may be just enough for it not to get enough fuel.

It has a carburetor and I tried setting the altitude at 0, 5K an 10K settings and everything in between. It was set at 5K and worked flawlessly up past the Jersey Jim Lookout Tower in Colorado...which is around 9K feet.

It may be a couple weeks before I can get out there to troubleshoot more, but I will get back on here once I am able to take a look at it and report my findings. Thanks again guys.

I will checkout rv.net.

6.7L MegaCab

1-2-3 - I apologize if I offended you. For some reason the app on my phone showed you as having only 2 posts, so I thought you were someone just getting started here...I now realize that was not case and you spoke with authority. I did check the link you provided and there was an overwhelming amount of info on there--tons of experience. That code goes down many different routes and each model of the same generator can have different problems for the same code. Thank you again.

1-2-3

No worries. I didn't take any response you had like that. There's too much more important things in life to do that. I've actually been away form the board for awhile. Life and work and other things. I'm just now getting back into it now that I've upgraded to the '12.

I actually know two guys personally on the site I sent you too and one of them I work with and he collects and restores those generators. He's a painter and he paints some of them like show cars. Not sure what someone would need a barn full of them in better than showroom condition but that's what he likes to do and he probably knows more about them than the factory does. If I run into him and remember about this, I was going to direct him your way.

6.7L MegaCab

Good deal! Yeah I hear ya. I'm not able to get on here as often as like either. With 4 kids, makes it a bit tough.

I keep going back and forth on it, but I'm starting lean towards getting rid of my 2010. It's been nice, but keep having TIPM issues. With at least 4 years left in the military until I can retire, I may move on to something newer. With 108K on my truck, things are starting to need to be replaced.

That would be great If you run into your friend and can point him my point my way. Based on all I've read, it could be anything from electrical to fuel related or a new carb because it sat for a couple months in the shop. Before we left on vacation in July I did top the fuel off and added fuel stabilizer so I would think the fuel is still good and that it could be a filter issue. But apparently these generators are great until something goes wrong. The kids dirt bikes ran flawlessly with the same fuel so I think it is good.

Hopefully we can get it figured out before too long. We may be taking it out over Thanksgiving if the generator will run.

KATOOM

To the best of my knowledge of how these generators operate, the fuel pump continues to run while the engine runs and no siphoning takes places in order to supply fuel. I understand that the fuel pumps on these little Onans can be problematic.

6.7L MegaCab

Oh really? I will say that I could feel the pump run when priming but it didn't feel like it was running after it started before shutting off after a few seconds to a minute or two, so maybe it could be the pump.

I'll check that again, maybe next weekend.

KATOOM

When I bought my toy hauler with an Onan 5500 I couldn't get it to run. After going through the basic mechanical 101 process of establishing fuel and spark, I eventually found out that the fuel pump wasn't working. Thats when I also learned that the fuel pump can be common issue due to lack of use and fuel gumming. Not all auto parts places sell the exact Onan looking version either but thankfully a local place had one.

That said, maybe I could have gotten my generator to run more erratic like yours is does but when I bought my trailer the fuel cell was completely dry which means that there was zero fuel in the lines.

6.7L MegaCab

Well, I decided to just order the fuel filter and spark plugs. I'm on the fence on ordering a fuel pump. Found an AirTex E11015 replacement for $50 compared to the $80-$100 for the OEM pump.

When we bought the trailer, the fuel cell was about 1/2 full. The previous owners said they always added a fuel stabilizer when they filled it. After I ran the tank down some, I filled it back up and added fresh fuel stabilizer as well, so at least since we've owned it, it's always had fuel treatment ran through the system. The generator has almost 500 hours on (we put about 50 hours on it). It was serviced in 2012 with new spark plugs, fuel filter, and a valve adjustment, so maybe it is time for a new filter and it's possible the pump isn't performing as it's peak anymore.

I just find it odd it worked perfectly in May on our trip to WA and again going to NM and CO in July.

Hopefully the fuel filter and new plugs will do the trick! I'm going to try to get out there next weekend if the parts come in on time.

6.7L MegaCab

I just came across a parts listing and noticed there are two fuel filters, one directly on the fuel pump and one connected to the carb, both using the same part number.

KATOOM, does your generator have two filters? My trailer is parked at the base, which is about a 30 minute drive, so I can't verify until next weekend...if I can make it out there.

KATOOM

Yes, I believe when I installed the fuel pump there was a metal filter you screw on the pump, and there is also a metal filter screwed to a 90* fitting on the carb. A plugged filter would allow the engine to run under no load, unless it was really plugged up whereby it would possibly act like you described. That said, I'd certainly replace the one on the fuel pump first since it would seem obvious that its going to plug before the second carb filter.

Just the other day I ran my gen, as I do about every 2 months for around 15-30 min, and you can clearly feel the fuel pump when priming but yes, its hard to tell if its running when the generator is running. I guess to be absolutely sure I could check voltage to the pumps wire connectors. But in all the years I've worked on engines this would be one of the only I've ran across where the fuel pump doesnt run full time. Its just not logical to think that Onan would rely on gravity to feed the engine enough fuel. Especially with the multitude of variables they would be out of control with installation from the trailer manufactures regarding the fuel cell placement, lines, etc... Onan provides a stand alone system, which in my book would mean a fuel pump capable of supplying that system without other variables involved.