Onan 5500 in Cyclone is throwing Error Code 58 (Exhaust Gas Temperature Shutdown)

Ladiver · Aug 21, 2018

I have an odd issue and can't find the problem. At first, I could not get the generator to start, but after some fiddling around and adjusting the altitude setting, we got it to fire up. With no load, the generator surges dramatically. When I add a load, it will run for a minute or two then stop with an error code 58.

Has anyone had any experience with this error code or how to find the problem? I took it to an RV repair center and they fumbled around for several hours, then stopped when they could not figure it out. They wanted to replace the muffler(?) and see if that would resolve the problem. Then they realized the amount of time just to access it would not be worth it. I asked if they checked the compression and they said they can't do that at their shop. So...they sent me home with a small bill and never identified the problem. Next stop may be Onan Service Center. :-(

If anyone knows of a good generator mechanic in Orange or Los Angeles counties, please let me know. Or if anyone knows how to remove the generator completely! I can either try getting it fixed or just add more batteries and a solar panel to the setup.

Thanks,

Jeff

LBR · Aug 21, 2018

Ladiver said:
I have an odd issue and can't find the problem. At first, I could not get the generator to start, but after some fiddling around and adjusting the altitude setting, we got it to fire up. With no load, the generator surges dramatically. When I add a load, it will run for a minute or two then stop with an error code 58.

Has anyone had any experience with this error code or how to find the problem? I took it to an RV repair center and they fumbled around for several hours, then stopped when they could figure it out. They wanted to replace the muffler(?) and see if that would resolve the problem. Then they realized the amount of time just to access it would not be worth it. I asked if they checked the compression and they said they can't do that at their shop. So...they sent me home with a small bill and never identified the problem. Next stop may be Onan Service Center. :-(

If anyone knows of a good generator mechanic in Orange or Los Angeles counties, please let me know. Or if anyone knows how to remove the generator completely! I can either try getting it fixed or just add more batteries and a solar panel to the setup.

Thanks,

Jeff

Why did they stop when they could figure it out?

Ladiver · Aug 21, 2018

LBR said:
Why did they stop when they could figure it out?

Oops. After all that typing I forgot one little word. "not" LOL

I have updated my post. They could not figure it out.

NWILSON · Aug 22, 2018

My first guess would be that it's running too lean. That would cause surging as well as high exhaust temps.

What's the history of the unit? Have you been using it and this just started?....could mean a clogged filter. Has the unit sat unused for an extended period?...could mean fuel has deteriorated in the carb clogging ports. If the unit isn't too old you may be able to clean the carb and reassemble with old parts. Sadly, Cummins doesn't offer a rebuild kit; a new carb would probably be the cure.

PondSkum · Aug 22, 2018

I also say it's running lean. Meaning it's not getting enough fuel to the engine. That will cause it to surge and will also cause excessive heat build up. When I got my RW it had sat for 2 years with old gas in the generator system. I cleaned it out and put fresh fuel and fuel treatment. Finally got it running and it was surging and overheating also. I cleaned the carburetor 3 times to get all the buildup out of the jets, and it still didn't want to run. I finally had to replace the fuel pump and filter. After that, it has been running fine ever since. If your unit has sat for a while with old gas in it, the pump and filter could be gunked up as well as the carb. First and easiest step is the pull the carb off and clean it up with some spray carb cleaner through all the little holes and jets.

LBR · Aug 22, 2018

It is recommended here to run the generator at least once a month, under a heavy load, and of course not to let the gas get too old and ripe.....treat the gas in tank unless you know you will burn that tankfull in a short term boondocking.

I had to bring ours back to life after it sat unfired for about 5 months...mainlining high doses of Seafoam into the carb, treated the gas with Seafoam, and about a month of pampering it worked for me.

carl.swoyer · Aug 22, 2018

NWILSON said:
My first guess would be that it's running too lean. That would cause surging as well as high exhaust temps.

What's the history of the unit? Have you been using it and this just started?....could mean a clogged filter. Has the unit sat unused for an extended period?...could mean fuel has deteriorated in the carb clogging ports. If the unit isn't too old you may be able to clean the carb and reassemble with old parts. Sadly, Cummins doesn't offer a rebuild kit; a new carb would probably be the cure.

I'm wondering if you could do a conversion to LP?
Burns clean and doesn't turn into laquer when not used for a long time.
Mine is 12 year's old and in it's second fifth wheel.

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Ladiver · Aug 23, 2018

Yes, this has sat for almost a year. I drained the fuel out of the carb, but not out of the filter or pump.

I had had sea foam in with the fuel, but tonight I drained the fuel tank. Tomorrow, I will add fresh fuel. I will also replace the fuel filter (since I have one).

i have a second carb that has been cleaned and it performed exactly the same. I can try more cleaning this weekend. I may pull the carb from my neighbors SOB toy hauler and see if that works.

LBR · Aug 23, 2018

Ladiver said:
Yes, this has sat for almost a year. I drained the fuel out of the carb, but not out of the filter or pump.

I had had sea foam in with the fuel, but tonight I drained the fuel tank. Tomorrow, I will add fresh fuel. I will also replace the fuel filter (since I have one).

i have a second carb that has been cleaned and it performed exactly the same. I can try more cleaning this weekend. I may pull the carb from my neighbors SOB toy hauler and see if that works.

Go to YouTube..... Seafoam has a couple of videos. One of them shows how to bring an ailing 5.5 back to life like I did. Mine would run, but needed help .

Either that video or another one shows how to resurrect a 5.5 with Seafoam that won't even start.

Ladiver · Aug 23, 2018

Will do. Thanks.

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NWILSON · Aug 23, 2018

Make sure fuel will flow freely from tank to generator too. Stale fuel can collect anywhere.

porthole · Aug 23, 2018

One of the problems with ethanol laced fuel is degradation of rubber fuel lines, even 'supposed' ethanol safe fuel lines.

Did you see my thread on Onan problems?

Ladiver · Aug 23, 2018

Tonight I finished draining the fuel tank and lines. I disconnected the fuel filter from the pump and added a new one. I had a secondary line going directly into a gas can with fresh fuel and 2oz of seafoam. Generator still starts and surges, no nasty crap spewing out of the exhaust. ran it for about 5 minutes, then let it sit for 15. I came back and started it again. It still surges. I have a fuel shutoff valve inline between the pump and the carb, so I removed that to eliminate that potential. Still surges so I put it back. Then, I decided to actually watch the fuel go from the can through the line to the pump and into the carb. I think I may have an issue with the pump, but I don't know if that would cause the surge. Watch the video and let me know what you think.

porthole · Aug 24, 2018

Did you see my Onan page?

As to your video:

You have a carb with a float bowl, when the float drops fuel goes in, when the float is at the preset level, the needle valve will shut off the fuel flow.
You will have stop and go fuel flow because the bowl has to have a supply capability a percentage over maximum fuel flow.

Ladiver · Aug 24, 2018

Yes, I saw your page. I will try the solenoid tapping tonight. I am still going through the rest of the posts.

Thanks for the explanation on the float. I guess the pump is working as it should be.

Ladiver · Aug 24, 2018

Well, the tapping trick did not work. When the engine cools down, I will try a different carb (again) with the tapping method.

Ladiver · Aug 27, 2018

Ugh, my other carb won't even run! I hate this thing! I know I completely disassembled everything, soaked in SeaFoam, blown out with compressed air and still won't start.

BLR · Aug 27, 2018

Ladiver said:
Ugh, my other carb won't even run! I hate this thing! I know I completely disassembled everything, soaked in SeaFoam, blown out with compressed air and still won't start.

I now you said you drained everything however could some old gas be in the lines??
It literally took DH about 4 weeks to get ours to work after sitting for 4 months waiting for warranty work to happen

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Ladiver · Aug 27, 2018

No, there is no old fuel. I am running a line directly from the pump to a fuel can with fresh fuel.

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porthole · Aug 28, 2018

Was you other carb new?

I have several new Onan parts.
Carb, air and fuel filters, plugs and the fuel cut off solenoid.

Onan 5500 in Cyclone is throwing Error Code 58 (Exhaust Gas Temperature Shutdown)

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