Onan 5500 Generator Dies - Page 2

sundancer 87 · 08-19-2015, 10:24 PM

What gives you the impression the OEM pump is a centrifugal pump Pirate?

WifiDan · 08-19-2015, 10:29 PM

Haha! Filmore Utah... I drove too fast through there one time years back on my way to Vegas. Quite an adventure once the local authorities caught up lol!

Pirate · 08-19-2015, 10:29 PM

Well...the pump spins...thus its centrifugal.

If it had a lever arm and diaphragm bellows...it would be a positive displacement pump.

Make sense?

Pirate

Pirate · 08-19-2015, 10:32 PM

Dan,

Well you'd probably have no problem now. The posted speed limit on the interstate is now 80 MPH.

Would have been fun back in the 80's when I had a corvette!

Now just the slowpoke pulling that huge 5th wheel and going 65

Pirate

WifiDan · 08-19-2015, 10:35 PM

Well to be honest it wasn't too many years back and they were testing the 80mph then. I was testing somewhat higher than that!

sundancer 87 · 08-20-2015, 12:17 AM

Quote:

Originally Posted by Pirate

Well...the pump spins...thus its centrifugal.

If it had a lever arm and diaphragm bellows...it would be a positive displacement pump.

Make sense?

Pirate

Or it could be a rotary vane pump, they spin also. A gear pump such as the fuel dispenser pump in our toy haulers spin also.

Basically a centrifugal pump consists of a impellor and a volute with an intake and discharge port to be branded as such.

The main point about a centrifugal pump is it can't pump air. Therefore if the tank runs dry the centrifugal pump can't pick up the liquid again unless the pump is lower than the source and the air inside the pump is bled out.

Tanman · 08-20-2015, 05:44 PM

I am going to throw something out here that happened to me just last week. My generator was running and on its very own just died while I was washing the beast. It was hard to restart and when It did start it would run a little while then die.. It pulled code 45. Hmmm. I called a mobile generator man who responded with a new control module. Code 45 does not relate to the module but he thought it might be the problem. He checked the brushes, which were good then changed out the module. It worked fine without any codes..
The point is it may not be the fuel pump or fuel problems but rather the module board which caused mine to act screwy. As a side note they are not cheap.. I was given a 500 dollar cost to me for the board.. ouch plus labor..double ouch.
The repair guy stated this board controls EVERYTHING about the generator and how it runs..
Also my gen is a onan 5500 also like yours..

donzinger · 08-20-2015, 06:15 PM

Tanman - do you happen to have the Onan Part Number?

Also is yours the HGJAB model?

Don

Tanman · 08-22-2015, 08:58 PM

DONZINGER yes i do happen to have the part number and yes it is a HGJAB.. i will send it when i get a minute.

donzinger · 08-22-2015, 09:01 PM

Thank you! No rush

Pirate · 08-22-2015, 09:06 PM

Tanman,

On mine, it was always code 6 or 61...which in the manual says is the Generator died with no command from the controller.

Without getting out all the Onan stuff...wonder what code 45 is?

Pirate

Tanman · 08-22-2015, 11:58 PM

Donzinger....It is a Cummins part or at least it's in a Cummings box.
the part number is on the box and paperwork A032Y912 it is called a control PC Board.
That second digit is a zero.. I tried to find it on the web but could not. I would love to know what it really cost and not the come to the house and fix it cost.

donzinger · 08-23-2015, 11:18 AM

Thank you. I may have to go this route if my search for a loose wires turns up nothing.

Tanman · 08-23-2015, 12:39 PM

my gen would not even start right and when it did it ran poorly and died for no reason. Once the new board was installed it started right up and ran smoothly like old times.. strange but as the generator repair man said, this board controls everything about the running of this unit. Its like the brain . Its not a cheezy little board.. its about 6x6 x1 with some type epox covering.

jeffwelsh · 09-22-2015, 06:41 PM

Looks like adding the fuel pump to the back is the answer. Ran for several hours like a champ over the weekend. The only thing I would do different was maybe add a rubber grommet or something to isolate the pump from the frame. In the garage I can hear the back pump running. That maybe a winter project for me. I am also cross posting the other thread going on this topic. Here is the thread where I posted some pics. http://www.dutchmenowners.org/forums...in-3475-5.html

jeffwelsh · 07-19-2016, 05:26 PM

Its been almost a year and I just had my first problem since adding the pump in the back. Was running fine for about an hour and a half with both AC units on while I loaded up. I was about to shut if off and I heard it stumble. About a minute later it died with code 36. This time would not restart. I was near 90, so I let it cool down for about 30 minutes and still would not start. I could hear the back and front pumps prime. I took the fuel line loose from at the generator before the onan pump and primed and got plenty of fuel. Put it back on and checked oil levels let cool another hour or so. Still would not fire. I took the fuel line loose from the onan pump to the intake and there was plenty of pressure. I put it back on and it started right up and ran fine. My conclusion is that maybe the back pump I added is overwhelming the onan pump or is causing too much pressure on the onan side and overwhelming the float. Thoughts?

I'm thinking about removing the Onan pump and just letting my rear pump do the job. I'm thinking I really don't need two pumps. Thoughts?
-Jeff

Pirate · 07-20-2016, 03:34 AM

Jeff, I'd do some more looking first. Honestly, can't remember if the Onan pump has a filter between it and the carburetor...but that's where I would start.

The fuel pump you added at that back is a centrifugal pump...I'd bet...and that shouldn't overwhelm the Onan pump. Old time positive displacement pumps...that's different.

I also suspect that your experience is not that uncommon with fuel filters...drain a little out and the blockage sort of clears...for a while....

We've been boon docking above Cooke City, MT for three days...generator never missed a beat. That means we could watch DirecTV...and the generator didn't help with the programming at all! LOL!!!

Pirate

jeffwelsh · 07-20-2016, 03:43 AM

The filter is before the pump, I have replaced the Onan pump and filter before putting in the rear pump. You could be on to something getting plugged then when the pressure comes off if frees up till next time. Since its long past the filter it would be between the pump and the float bowl.

Pirate · 07-20-2016, 03:52 AM

So perhaps disconnect the hose from rear pump and Onan pump and use compressed air to
blow it out and see if you get anything?

Might also look at the fuel line from the rear pump into the tank. Might blow that out too? Just take the fuel cap off before you do.

Just thoughts,

Pirate

Whodatdude · 08-22-2016, 04:14 PM

Quote:

Originally Posted by WifiDan

Please do! I am going to try a new pump before our trip this weekend and update if it fixes it!

WifiDan, what did you do to resolve your issue? I'm curious because I just bought a 2017 Voltage and had the same problem the day I brought it home. The dealership says it's not a problem with the RV, the Onan experts in Austin say the generator is not big enough to handle that load. I have a 5.5 Onan. Every toy hauler that I looked at had the 5.5 Onan, so I'm pretty sure it can handle it. I see that adding the fuel filter worked for Pirate and jeffwelsh. Just curious if you went this route, as well.

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