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Onan QG 5500 EVAP fault code 58

SouthernLoCo
Explorer
Explorer
I just purchased a Jayco Seismic TH from camping world in Dec. of 2014. The trailers has a factory installed Onan 5500 (model # 5.5HGJAB-6755K. When trying to start it for a maintenance run, I somehow flooded it. Proabably over primed it. I was finally able to get the thing started and it sputtered and blew black gunk out of the tail pipe.

Once it was cleared itself, it began running just fine. Maintains constant throttle, no loud noises....nothing. Howeever, it will run for about 10 to 15 minutes on the initial start-up, then stops itself. Throws error code of 58 which is high exhaust gas temp. Looked in service manual, and it says to take to dealer.

Not wanting to down my trailer at the dealership for a month, I called Camping World for tech support. They were nice and courteous, but could not answer my question. Said he would have to call Cummins. I tried calling Cummins too, but was told they will absolutely not give tech support over the phone. Go figure! A customer wants to troubleshoot before bringing item in for warranty issue, and no help! No customer appreciation now days!!

I've looked at other forums and finding no help. Seen everything from bad magneto, to varnishing of carb, etc. My unit runs great before the exhaust heating up and throwing code 58.....every time. Under load and not under load. Engine is clean as a whistle and brand new (2015 trailer). Has 22 hours on it. Gas is clean.

I've taken the spark arrestor out and ran the unit as per service requirements. It still cuts off. Did not blow much of anything out of the spark arrestor hole.

I'm at a loss. Any idea would be appreciated.

Thank you
11 REPLIES 11

IB853347201
Nomad
Nomad

I'm thinking the fuel pump is your culprit. Install a new one, should fix issue. 

2010 Suncruiser

No the fuel pump is pumping all kinds of fuel and when the generator dies the bowl of the carburetor is still full of fuel.  I don't think its a fuel delivery issue.  I started a new thread for this since this one is so old.  It lists all of my troubleshooting and symptoms in more detail.

https://community.goodsam.com/t5/technical-issues/onan-generator-code-58/td-p/3679815

SouthernLoCo
Explorer
Explorer
Smokestack has been no help yet, so still searching for help

Did you ever figure out the issue that was causing this?  My geny is doing the same thing.  Runs great but shuts off after about 10min with code 58.  Doesn’t surge starts right up.  I can’t figure out the issue.

You are responding to a post that's almost 10 years old. You may have better luck asking your question in a new post. 


Jeff - 2023 FR Sunseeker 2400B MBS

Yes but my issue and troubleshooting to date match the original post exactly so was hoping the original poster might respond with what solved their problem.  Figured it was a long shot but worth pinging them if it can expedite me finding a solution.

SouthernLoco hasn't posted on the forum since 2016. But lots of folks on here (well that used to be on here) are familiar with genny issues. I think you'll get more traction if you posted a new question. 

That said, code 58 is High Exhaust Temperature. From what I've read it usually comes from running too lean. If cleaning the carb etc does not fix your problem, some folks have had luck replacing the fuel pump and filter. 

The root of these problems is usually when the genny sits dormant. The fuel will varnish. It's recommended you run your genny once a month under a load for an hour or so to help mitigate some of these issues. 


Jeff - 2023 FR Sunseeker 2400B MBS

SouthernLoCo
Explorer
Explorer
No, I haven't. Will try there.

sdetweil
Explorer
Explorer
have you looked on smokstak for onan
they helped me fix my 7kw genset
2012 Ford F350 DRW, 6.7 diesel.
2013 Keystone Alpine 3720FB

1492
Moderator
Moderator
Moved from Technology Corner

SouthernLoCo
Explorer
Explorer
First of all, sorry about the typos on the OP. Took out the exhaust gas sensor and the probe seemed clean. Put back in, started, and put load on generator. Made it 10 minutes, shut down with code 58. Just keeping y'all advised. Thanks