scratching my head over my A/C

[jim1eddoc]

2011 vista..
A/C and generator will quit almost immediately when running on generator while moving down the road.
1. A/C will run forever on generator while sitting still.
2. A/C will run forever when plugged into 120v
3. generator will run forever sitting still or moving down the road.

doesn't seem to matter if the road is rough or smooth both systems will quit when moving. Which starts the problem, generator or A/C?

[BFlinn181]

Have you allowed generator to warm up and stabilize before starting the A/C? If so, next I'd check voltage output of the generator. I'd suspect generator causing the problem, not A/C. You might plug a Kill-A-Watt into an outlet to monitor generator output.

[Podivin]

Is there a speed at which they cut out, or is it as soon as you start moving?
The only thing *I* can think of that's different between sitting running the genny and AC, and driving running the genny and AC is the air movement across the AC (I'm assuming roof mount). So wondering if it's speed related somehow (too much air across X device is causing a problem).
If you have an air compressor and a hose, can you make it cut out while plugged in to shore power by blowing air around the AC unit?

[harleyjt]

Concentrate on the generator. I suspect it's dying and killing the A/C. Do you have a full or nearly full tank of fuel? If you are near 1/4 tank there may be enough fuel to pick up and run sitting still but when moving with fuel sloshing around you may not be picking up fuel. Not sure if this is carbureted or FI genny, but if card you might check and see if float bowl is empty after it dies. That would confirm a fuel issue.


jt
2005 Newmar Kountry Star gas 3742, Workhorse 8.1L w/Allison 5 speed.

Sent from my iPhone using iRV2 - RV Forum

[Podivin]

Fuel level, that's a good thought. Especially if where rig sits is not exactly level, allowing fuel to 'pool' underneath the generator fuel pick up.

[twinboat]

Wild guess, but did you change the gas cap ?

Generators use more fuel running AC. If the cap vent is blocked, the combo of the engine and generator could be starving the generator fuel.

Try it with the cap lose.

[DancinCampers]

Transfer switches have been know to disengage on the highway.

[twinboat]

Originally Posted by DancinCampers

Transfer switches have been know to disengage on the highway.

But that won't stop the generator engine.

[harleyjt]

Cap loose is a good idea.

[SuperGewl]

Check wires on AC side of house for a possible break in the wires causing a short only when moving. You would only see this when moving forward and on generator due to not being able hook up a ling enough shore power cable run AC while traveling.
You could hook up to Shore Power turn on the AC then start wiggling the wires from the AC to see what happens. Pull the inside cover off the AC and take a good look at the AC line there.
Good luck.

[motohomo]

Also check oil level. Low oil can cause this too

[bodycoach2]

Do you have a generator Auto Start? If that is installed, it will turn off your genset as soon as in motion.

[jim1eddoc]

don't have a gen-start. rv service went through the generator...oil and all filters.

[grtharris]

jim1eddoc, what is the error code when the generator stops?

[Mich F]

I had problems with the generator shutting off when moving, on a previous RV. In my case it was the low oil shut off, not working properly, and shutting off the generator. If it was parked on level ground, it would run forever.

[jim1eddoc]

generator code when it shuts off? where would I find a code... it's a 4.0 onan on 2011 vista.

[BFlinn181]

The LED on the control switch will blink codes if it has error messages. See page 31 of this manual to interpret the blinks, and that your generator is equipped to flash them.

http://power.cummins.com/sites/defau.../F-1123-EN.pdf

[grtharris]

jim1eddoc, you should have a generator manual in the bag of stuff that came with the coach.

[jim1eddoc]

got the section re: generator out.. i'm not into working with dots and dashes to determine the problem. so... i'll contact my rv repair facility, let them know i'm coming, turn on the system so it will cut out by the time I get there. pull in with the coach running and say... now... read the trouble shooting screen on the generator... they will have to fix the problem anyway..

thanks for all the input. i'll report on the cause of the problem.

[mtnmike]

I think MIch F nailed the problem. The low oil shut down does not mean that you necessarily have low oil, (although hopefully you have visually checked to see that it is full). I had the same problem on a portable generator and it was a loose wire from the low oil sensor. The vibration of the gen-set would shut down the engine.