Generator madness!!

[plyonsMC9]

Greetings fellow busnuts,

We have had a generator problem for the last several years that we have not been able to solve.

We have a Kubota 10Kw Diesel generator.

It operates just fine when the vehicle is not in motion.  It can run a number of days w/o stopping.

It operates w/o problem when driving down the road - if the ride is steady - e.g,. no sudden braking operation by the bus.  Either fast or slow speed - as long as it is steady. It can run for hours, or that is probably about as long as I have been able to maintain a steady speed on the road.  :-)

Problems occur when the vehicle is in motion, and the brakes are applied.  The generator cuts out.  Sometimes it can be restarted.  Sometimes not - just doesn't "catch" when trying to turn the genset back on.  Cranks just fine. 

The generator has a baffling system, high power fan blowing air through the radiator fins, As soon as the generator starts, air is blasting through - very noticeable air flow coming out from under the bus.  This system is to cut down on the noise coming from the generator when we are parked.  It does a good job, and again, this all works very well when going down the road or parked.  Running fast or (i think) slow.  Only issue is - applying the brakes, especially in a quick stop.  Or, Coming to a complete stop, like when just leaving a parking space, or the driveway at home, end of the block, etc...

Have called friends, Wrico generator, etc., still no go.  Makes travelling in heat very uncomfortable.  (over the road a/c still not working either - also after NUMEROUS attempts & repairs).

What we have tried:

Shortened fuel feed line by a couple of inches.  Original 1/2 copper line seemed to go almost to the bottom of the tank.  I was concerned about maybe some  piece of large sediment blocking the tube, but this did not help.

Checked all wire connections to generator, that i can find. All seem very secure. 

Made sure fuel feed lines are tight.

Made sure blower to cool generator is blowing strong.  Not quite sure how to test this?  It is always blowing strong when parked. 

Don't know how to simulate or test a "stopping" motion.  Or, why the generator would cut out when stopping. 

Changed fuel filter.  Changed oil filter.  Air bled fuel system.

Wrico felt it had to do with air flow.  However, they are not able to visually inspect since I am in Illinois and they are in California.

Help!!!  Any thoughts or suggestions?

OR - a good quality diesel generator repair person somewhere around Chicago IL?

I'm really out of ideas - a friend has suggested lightly tapping components with a rubber mallet, but I'm not sure I trust myself with this. 

Thank you!!

Phil

[Utahclaimjumper]

Phil, I have had a simular problem in the past, solved it be installing a pusher type fuel pump close to the fuel tank to provide a steady flow to the generator, no problem since.>>>Dan

[plyonsMC9]

Dan - this sounds interesting.  Can you provide more specifics?  Thank you!!

Phil

[Len Silva]

Phil,

First, you have to determine if it's an electrical or fuel supply problem.
Do you have any kind of indicator lights and/or gauges that you can watch?
If not, then wire up a simple indicator light to the fuel stop solenoid.  If it goes off when the problem shows up, then it's an electrical problem.  If not, then it's probably starving for fuel, though I can't imagine why.

The next step might be to hard wire battery (through a fuse/breaker) directly to the fuel solenoid, disconnecting the existing lead.  If that cures the problem, then it's definitely electrical in nature. You won't be able to shut it off and all safeties are defeated in this configuration.  It's only temporary.

There are many things that could interrupt the power to the solenoid. Low oil pressure, low oil level, high temp etc.  More likely that it's a loose connection, bad sensor, bad relay.

If you have a schematic, post it here, maybe we can help further.

[Utahclaimjumper]

Phil, Is you fuel system hardlined?? can you install a temp. rubber line and mount a temp. 12V pump?? worth a try with minimum work.>>>Dan

[plyonsMC9]

Dan, yes my system is hardlined, brass connecters at fuel tank.  Rubber fuel line to generator.

What kind of 12 volt pump would I get?  What kind of gallons per minute would this pump be?   

I need coaching!! 

Thank you - Phil

[luvrbus]

My 15 kw came with a Facet electric pump mounted on the engine, like Len recommends check the solenoid with a little age it will get weak and shut down.  
Mine opens with 12v for start up then goes to 110 v to stay open.
I hope that is not the problem Dick Wright charged me 283.00 bucks for 1      

good luck

[plyonsMC9]

Hi Len,

Could you coach me a bit more on the indicator light?  My setup has no indicators, other than the voltage guages inside the rig.  I would like to have more troubleshooting lights, but unfortunately, have a lot more computer skills and very few mechanical skills. Always trying to learn though.  I think I can follow your idea on the direct hookup of the fuel solenoid.  I will scan, and then post schematic when we get the bus back in town.

Thank you!!

Phil

[plyonsMC9]

Hi luvrbus - haha $283 would be inexpensive compared to dealing with the family rebellion when it gets to be 90 degrees or hotter inside the bus.   

Seriously - the generator is 4 1/2 hears old.  Is that old enough for this pump to get weak?

Thank you!

Phil

[JackConrad]

Phil,
    Pick-up a 12 volt indicator light at any auto parts store. Run one of the leads on the light to the power wire at the fuel pump and ground the other wire from the indicator light. Then try the generator.  If the light goes out when the generator stops, you have an electrical problem. That could be a bad sensor, relay, connection? 
    Are you sure your generator oil level is correct? Low oil level can cause a low oil pressure situation when braking or hard turns as the oil sloshes away from the pick-up. 
    We had a problem with our generator starting and found a loose connection inside the control box that PowerTech installed on our generator. I know another person with a PowerTech that had a similar problem. You might want to check all connections inside the control panel. 
     Does the generator stop at the instant you brake hard or a few seconds later?  If it is stopping at the instant you brake, it is probasbly an electrical issue.  It is takes a few seconds, it may be a fuel issue.  Jack

[WEC4104]

Just as an outside observer, reading what has been described, I'm thinking the problem is somehow related to sloshing liquids.  The fact that it can happen at parking lot speeds, leads me away from the air flow causes.

The most obvious liquid would be the fuel feed, but it sounds like this has been at least partially checked over.  I'm wondering about how easy it might be for you to hook up a fuel pressure gauge to monitor while drive.

I am also not discounting the possibility of oil or coolant sloshing.  If there are level sensors tied to an auto shutdown circuit, perhaps there is a way to bypass the sensors just for testing.  You could also temporarily drain either of these liquids a bit, just to see if the sensitivity worsens.  By any chance, have you noticed the problem being more prevalent when you brake going down a hill? (ie: bus is already tipped forward, exaggerating the slosh.)

One more piece which might help:  Has the problem existed as long as you have had the generator, or did it start appearing sometime during ownership?

[Utahclaimjumper]

Phil, I have a Facet standard automotive fuel pump 12V that can be had from most auto supply stores (like NAPA) they work better "pushing" than pulling, and I have it wire into the "on" switch for operating the Gen. ( they are not that expensive)<<<Dan

[Lin]

Is the fuel pickup toward the back of the tank?  If so, maybe the fuel rushes forward when you are stopping leaving the pickup sucking air.

[plyonsMC9]

Thanks Dan- this sounds like a good piece of test equipment or piece to the solution - will pick up on Monday.

Best Regards, Phil

[luvrbus]

I am with Len about it being an electrial problem when you run one out of fuel they are hard to start without a electric fuel pump 
good luck