Onan Genset problem

[Ed Dubois]

Hi,

It's winter for real around here (SW BC). There are piles of snow around and the roads are glistening with salt crystals and ice so I'm glad our RV is well winterized and covered at the moment.

Our problem: the genset (7KW Onan HDKA –J1145F with approximately 800 hours on the meter) in our 2001 37 ft Patriot isn't cooperating. When we tried to exercise it it started normally but then cut out in 30 seconds or so. It started again and cut out more quickly. We tried once more and it cut out in about 5 seconds.

The first level fault code showed 2 blinks, which our manual says means “loss of oil pressure”. The oil and filter were changed at the end of the summer and the genset was run for approximately 3 hours after that change.  The oil level is full as is our fuel tank.

We’re not expecting to try to fix this problem ourselves but would like to have some ideas on the probable cause. When we head for a repair facility we're more comfortable if we have an idea of what we might be in for.

All suggestions welcome!

Thanks.

Ed

[Steve Huber]

Ed
What is the outside temperature? You may not be getting much oil flow due to the cold temperature.
Steve

[Edward Buker]

Ed, Steve,

I would think that the oil pressure would be higher in the cold given the higher cold oil viscosity. It may be that the sensor is stuck, possibly due to the cold, and not sensing the true pressure and that is causing the fault.

Good question for an Onan tech in Canada. They should have seen this issue before if it is a cold related fault...

Later Ed

[Doug Allman]

You may behaving a fuel problem. The fuel to the genset is not heated as it passes thru the genset as it is when going thru the diesel pusher engine and excess fuel is returned to the fuel tank. The filter on the genset may be waxing up due to the cold fuel and blocking fuel to the motor.

Dave Atherton posted in regard to this problem with genset filter/fuel nozzle. He has indicated that for a northern application to eliminate the genset fuel filter plugging issue, including the blue smoke at cold start up, that you might add a small tank near the genset, fill it with a 911 fluid and have it drip the 911 fluid into the diesel fuel going to the genset. This would eliminate the genset plugging and also treating a full tank of diesel fuel just for the genset.

You could treat the coach fuel tank now and see if that cures the genset before any other maintenance is attempted for the genset.

[Ed Dubois]

Thank you all for your replies.

The temperature when we tested this was freezing but not all that much. It was maybe 20º - 25ºF. I've never had oil problems in this temperature range before but who knows? We also ran the engine for a while (CAT 3126B) with no issues. Next we'll try again when the temperature climbs (soon I hope). I'll also try to track down an Onan technician in this part of the world to see if we can learn something useful there.

Ed

[Steve Huber]

Ed Buker,
I've seen 0 oil pressure in MN when the temp gets very cold (< 0) and  there is a trace of water in the oil pump, If it does flow, you are correct re high pressure reading.

Doug,
Not sure I understand how a fuel problem can result in a loss of oil pressure fault. Help me understand this.

Ed D.
Be sure to let us know what Onan finds.

Thx! Steve