Onan issues

[Aphinn]

Morning folks having some issues with the generator it starts fine then shuts off after 30 seconds shows a 33 code gen serial is 8hdkak11451j any help appreciated

[jerichorick]

Originally Posted by Aphinn

Morning folks having some issues with the generator it starts fine then shuts off after 30 seconds shows a 33 code gen serial is 8hdkak11451j any help appreciated

I found this in the Onan handbook I have: "Fault Codes The genset controller provides extensive diagnostics by causing the status indicator light on the Control Switch to blink in a coded fashion. Following a fault shutdown, the indicator light will repeatedly blink one, two, three or four blinks at a time. • One blink indicates shutdown due to high engine coolant temperature. • Two blinks indicates a low oil pressure fault. • Three blinks indicates a service fault. Press Stop once to cause the two-digit, second-level fault code to blink. (Pressing Stop again will stop the blinking.)The two-digit code consists of 1, 2, 3, 4 or 5 blinks, a brief pause, and then 1 to 9 blinks. The first set of blinks represents the tens digit and the second set of blinks the units digit of the fault code number. For example, Fault Code No. 36 appears as: blink-blink-blink—pause—blink-blink-blink-blink-blink-blink— long pause— repeat • Four blinks indicates that cranking exceeded 30 seconds without the engine starting. Note: Fault Code Nos. 3 and 4 are first level faults. Avoid interpreting them as second-level Fault Code Nos. 33 and 44, which have not been assigned as fault codes.
Restoring Fault Code Blinking – The fault code stops blinking after five minutes (15 minutes, Series HGJAA). Press Stop three times within five seconds to restore blinking. Note that the last fault logged will blink, even after the condition that caused the shutdown has been corrected."

Hope this helps. Call Onan if all else fails.

Rick Y

[Aphinn]

Thanks I'm under the impression 33 fault code is high tempature code it has antifreeze in it and as it only runs 30 seconds can't see it overheating will try and chase some wires

[okcnewbie]

You should be able to find the service manual here;

Index of /~n0nas/manuals/onan

[Gary RVRoamer]

If the wiring harness has come loose from the coolant temp sensor (top of genset) and has shorted to ground (most anywhere on the genset itself), the controller will see that has a high temperature fault, regardless of the actual temperature. High temp is signaled when the temp sensor is closed, so a short looks just like an over-temp condition.

[ga traveler]

Get your ohm meter and check the temp sensor.

[RCLImperial]

There is another thread about this issue in this site, Class A Motorhomes. Do a search for "Onan 7.5 " to find it. The coolant sensor is a cheap part, but replacement labor can be expensive because the sensor gets corroded and doesn't come out in one piece, leaving part of it in place, requiring major disassembly of the diesel motor. Mine failed in 2009, but I was able into replace it without much difficulty. My gen set is on a slide, so removing the covers was easy. If yours is not slide mounted, you may have to drop it out to get at he problem.

Dick L. '04HR Imperial

[Aphinn]

Thanks for the responses I think we are heading in the right direction tomorrow's mission find that sensor and check to see if there is a fault I crawled under to look and it's not on the bottom will chase down the wiring thanks all

[Rbhein]

Mine was doing that last year. Turns out it was 2 wires in the transfer switch had shorted out. The genset would run until the transfer switch engaged, then would shut itself down immediately to prevent damage. Cummins shop diagnosed it as a bad stator. I discovered the real problem while waiting for them to get the new parts. Turns out all I needed was a couple feet of heavy wire.

[Rbhein]

PS. Does everything seem okay when hooked to shore power?

[8TiresRollin]

Friend has a Damon 40ft and his Onan would only run for approximately the same time as yours. Turns out the generator engine software looks for a coolant temperature change from the sensor IE wants to see the coolant start to warm. If it sees no change then the engine stops. He changed the sensor and now it runs fine but it took so long because his generator had to be dropped to do the work.

[alounsbe]

I had a similar issue on an Onan and it turned out it had a broken fan belt.

[Aphinn]

Thanks. For all the help turned out to be the temparure sensor after checking around found we had a onan rep 15 miles from home he removed the generator from the coach changed the sensor and checked the unit to see if it needed anything else 375 dollars later all is well

[JohnRR]

Thank you for the update they are important for those who may do a search of the subject in the future.