Generator shuts off above 90 degrees outside

[Phil_AZ]

Onan 5,500W (500 hours, regular oil/filter changes) Runs well below ~90degrees, sitting still or driving. I removed the front metal plate/cover which houses the generator, this helped keep the generator on slightly longer while driving.

Can I cut holes in the metal box that holds the generator in order to give it far more air flow? Maybe on one side, the back and the bottom? I assume I should leave the top solid to protect the rig in case the generator gets too hot/fire/etc.

Will this have the risk of allowing it to get too cold in the winter (although we do very little winter RVing)?

Thoughts?

[NXR]

What is the code when the generator shuts down? if 36, that means the generator shut down but it was not due to the control board sensing a problem. It's usually a fuel pressure or fuel boiling problem.

If nothing else, consider replacing the generator fuel pump. A lot of people have reported that fixes uncommanded shutdowns. This one may work: https://www.amazon.com/Electric-Gene.../dp/B07DG3B59B

Ray

The next time it shuts down, go outside and pull the generator cover off. There is a light on the switch. It will blink out a code if the generator detected a fault.

From the Onan service manual:

"FAULT CODES
The genset controller provides extensive diagnostics by causing the status indicator light on the Control Switch to blink in coded fashion. Following a fault shutdown, the indicator light will repeatedly blink 2, 3 or 4 blinks at a time.

• 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 purposely not been assigned as fault codes.

• Fault Code 36 means "I shut down but I have no idea why!". That means none of the monitored conditions, such as low oil pressure, caused the shutdown. It can be just fuel starvation.

Restoring Fault Code Blinking – The fault code stops blinking after five minutes (15 minutes, Series HGJAA & HGJAD). 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."

Hmmm, that last sentence says a fault code may still be blinking, doesn't it?

https://thecampingadvisor.com/onan-g...r-fault-codes/

Onan Generator Fault Code List
Code 2 - Low Oil Pressure
Code 3 - Service Check
Code 4 - Over Crank
Code 12 - Over Voltage
Code 13 - Under Voltage
Code 14 - Over Frequency
Code 15 - Under Frequency
Code 19 - Governor Actuator Overload
Code 23 - Low Oil Pressure Cutoff Switch
Code 27 - Voltage Sense Error
Code 29 - High Battery Voltage
Code 31 – Overspeed
Code 32 - Low Cranking Speed
Code 35 - Control Card Failure
Code 36 - Engine Stopped
Code 37 - Invalid Generator Set Configuration
Code 38 - Over Current (Field Overload)
Code 41 - Generator Rotor
Code 42 – Processor
Code 43 - Processor Fault Code.
Code 45 - Speed Sense
Code 47 – Ignition
Code 48 - Generator Field Sense
Code 51 – Processor
Code 52 - Fuel Injector
Code 54 - MAT Sender
Code 56 - MAP Sender
Code 57 - Over Prime
Code 58 - Exhaust Gas Temperature Shutdown
Code 81 - Exhaust Gas Temperature Sensor Open
Code 82 - Exhaust Gas Temperature Shorted

[Phil_AZ]

Started gen, turned off after 10 minutes (91 degrees outside). The red light on the "start" button simply is on/off with generator. When it shut down I don't see any lights/dashes blinking. I have a pic of the front of gen, but this message board won't let me attach it.

[Phil_AZ]

image attached

[NXR]

Try this:

Restoring Fault Code Blinking – The fault code stops blinking after five minutes (15 minutes, Series HGJAA & HGJAD). 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."

If you click Go Advanced rather than Post Quick Reply, you'll get more functionality including a paperclip to attach images.

Ray

[Greenhound386]

Originally Posted by NXR

Try this:

Restoring Fault Code Blinking – The fault code stops blinking after five minutes (15 minutes, Series HGJAA & HGJAD). 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."

If you click Go Advanced rather than Post Quick Reply, you'll get more functionality including a paperclip to attach images.

Ray

Dealing with a similar issue right now on my Onan, and the instructions above are exactly what I did in order to restore the code / blinking lights.

[NXR]

Originally Posted by Greenhound386

Dealing with a similar issue right now on my Onan, and the instructions above are exactly what I did in order to restore the code / blinking lights.

Thanks for the confirmation. What code did yours show?

Many of the "quits when hot" problems seem to get fixed by adding insulation to the fuel line in the vicinity of the the generator or replacing the fuel pump. Those things seem to be, or have been, problematic.

At least one person added a vent grill to the door of the generator compartment.

Ray

[Mooney 78865]

Here is a link to what I did to fix our Onan 5500. To this day it still runs like a champ. Only code we had was "uncommented shutdown"
https://www.forestriverforums.com/fo...ue-205195.html

[Greenhound386]

Originally Posted by NXR

Thanks for the confirmation. What code did yours show?

Many of the "quits when hot" problems seem to get fixed by adding insulation to the fuel line in the vicinity of the the generator or replacing the fuel pump. Those things seem to be, or have been, problematic.

At least one person added a vent grill to the door of the generator compartment.

Ray

I am getting code 36.

I started another thread today about mine, and it may have been an issue with the oil overfilled. I need to get the generator back to some hotter temps to be sure, but I did get the generator to run yesterday after letting some oil out.

[Dodge Guy]

Mine would do this on the road when it was over 90. Hit a bump hard enough and it would shutdown. It a.ways starts right back up. I did all the basics first. Plugs, filters, oil and filter, tried the oil a bit over and under full, still same issue. Replaced the fuel pump, still same issue. I came to the conclusion that the gas is boiling in the carb and when it gets jarred hard enough it sucks in the air bubble (vapor locking). So I cut and installed some stainless vents in the compartment door. This fixed it to 90%. The only thing left is to insulate the fuel line and carb.

They tell you not to cut the actual generator door as it needs it to pull the air in through the baffles.
The lower vents I installed on mine force air into the generator underneath, and then expell it out the rear. The uppers just vent the compartment.

If you look at most of the newer MH’s they have a screen vent from the manuf for this reason.

[ependydad]

Dodge Guy, where did you get those vents? That’s exactly what I want to do on my Jayco.

[Dodge Guy]

I got them from Amazon. They are a marine type vent. IIRC the tops are 9 slot and the lowers are 7 slot. All quality stainless steel.