Onan starting

K

ken harland

New member
Dec 30, 2005
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1
0
I've spent over an hour searching through multiple pages of search results with no luck so I will just my question straight out. When I start my
genset from either switch, it dies as soon as I release the switch. I know I've read about this problem before but the only thing I remember was it
will do that if it's low on oil. My is not so I'm left searching for a solution.

Anyone?

Thanks,
Ken
--
1978 Eleganza II
 
http://www.bdub.net/oddsnends.html

Check that out.

Sully
77 eleganza 2
Seattle

> I've spent over an hour searching through multiple pages of search results
> with no luck so I will just my question straight out. When I start my
>
> genset from either switch, it dies as soon as I release the switch. I
> know I've read about this problem before but the only thing I remember was
> it
>
> will do that if it's low on oil. My is not so I'm left searching for a
> solution.
>
>
>
> Anyone?
>
>
>
> Thanks,
>
> Ken
>
> --
>
> 1978 Eleganza II
>
>
>
> _______________________________________________
>
> GMCnet mailing list
>
> Unsubscribe or Change List Options:
>
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
 
Sorry, thought it was a more direct link. Try this

http://www.gmcws.org/Tech/dsimmons/onan/onan.html

> http://www.bdub.net/oddsnends.html
>
> Check that out.
>
> Sully
> 77 eleganza 2
> Seattle
>
> On Mon, Jan 9, 2017 at 5:55 PM Ken Harland

>
> I've spent over an hour searching through multiple pages of search results
> with no luck so I will just my question straight out. When I start my
>
> genset from either switch, it dies as soon as I release the switch. I
> know I've read about this problem before but the only thing I remember was
> it
>
> will do that if it's low on oil. My is not so I'm left searching for a
> solution.
>
>
>
> Anyone?
>
>
>
> Thanks,
>
> Ken
>
> --
>
> 1978 Eleganza II
>
>
>
> _______________________________________________
>
> GMCnet mailing list
>
> Unsubscribe or Change List Options:
>
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
 
I really miss Duane. Never met him but sure talked to him on the phone a
bunch.

Sully
77 eleganza 2
Seattle

> Sorry, thought it was a more direct link. Try this
>
> http://www.gmcws.org/Tech/dsimmons/onan/onan.html
>

>
> http://www.bdub.net/oddsnends.html
>
> Check that out.
>
> Sully
> 77 eleganza 2
> Seattle
>
> On Mon, Jan 9, 2017 at 5:55 PM Ken Harland

>
> I've spent over an hour searching through multiple pages of search results
> with no luck so I will just my question straight out. When I start my
>
> genset from either switch, it dies as soon as I release the switch. I
> know I've read about this problem before but the only thing I remember was
> it
>
> will do that if it's low on oil. My is not so I'm left searching for a
> solution.
>
>
>
> Anyone?
>
>
>
> Thanks,
>
> Ken
>
> --
>
> 1978 Eleganza II
>
>
>
> _______________________________________________
>
> GMCnet mailing list
>
> Unsubscribe or Change List Options:
>
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
 
Ya probably need to change the low oil pressure switch.

To check, you can jumper connection 5 to 9 on the printed circuit board to
see if that fixes it.

bdub

> I've spent over an hour searching through multiple pages of search results
> with no luck so I will just my question straight out. When I start my
> genset from either switch, it dies as soon as I release the switch. I
> know I've read about this problem before but the only thing I remember was
> it
> will do that if it's low on oil. My is not so I'm left searching for a
> solution.
>
> Anyone?
>
 
> I've spent over an hour searching through multiple pages of search results with no luck so I will just my question straight out. When I start my
> genset from either switch, it dies as soon as I release the switch. I know I've read about this problem before but the only thing I remember was it
> will do that if it's low on oil. Mine is not so I'm left searching for a solution.
>
> Anyone?
>
> Thanks,
> Ken
The first thing that comes to my mind is the voltage regulator. When the Onan starts running, the control board gets something like 28VAC on pin 8
from the flywheel alternator. That tells the board that the Onan is running. If it doesn't get that voltage, it shuts off the fuel pump and the
ignition. A faulty voltage regulator can pull that voltage down.

The second thing that comes to mind is the low oil pressure sender. A bad sender will ground pin 12 and shut it down.

A bad control board will cause grief too.

Common troubleshooting technique is to jumper pin 5 to pin 9. That bypasses the "not running" and "low oil pressure" protections. Try it and see if
it continues to run. If it does, you need to figure out if it is a bad board, a bad voltage regulator, or a bad oil pressure sending unit. Read the
GMCWS link posted previously to understand how to do that.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."
 
Ken,

Read the trouble shooting guide by Duane Simmons that I sent the link to.
Even if you read it slowly several times it will
Only take a few minutes. Then print it out and go out to your Onan and go
through the steps. There is no Onan issue he did not know about.

Sully
77 eleganza 2
Seattle

>
> > I've spent over an hour searching through multiple pages of search
> results with no luck so I will just my question straight out. When I start
> my
>
> > genset from either switch, it dies as soon as I release the switch. I
> know I've read about this problem before but the only thing I remember was
> it
>
> > will do that if it's low on oil. Mine is not so I'm left searching for
> a solution.
>
> >
>
> > Anyone?
>
> >
>
> > Thanks,
>
> > Ken
>
> The first thing that comes to my mind is the voltage regulator. When the
> Onan starts running, the control board gets something like 28VAC on pin 8
>
> from the flywheel alternator. That tells the board that the Onan is
> running. If it doesn't get that voltage, it shuts off the fuel pump and the
>
> ignition. A faulty voltage regulator can pull that voltage down.
>
>
>
> The second thing that comes to mind is the low oil pressure sender. A bad
> sender will ground pin 12 and shut it down.
>
>
>
> A bad control board will cause grief too.
>
>
>
> Common troubleshooting technique is to jumper pin 5 to pin 9. That
> bypasses the "not running" and "low oil pressure" protections. Try it and
> see if
>
> it continues to run. If it does, you need to figure out if it is a bad
> board, a bad voltage regulator, or a bad oil pressure sending unit. Read the
>
> GMCWS link posted previously to understand how to do that.
>
> --
>
> 73 23' Sequoia 4 Sale
>
> 73 23' CanyonLands Parts Unit 4 Sale
>
> Upper Alabama
>
> "Highest price does not guarantee highest quality."
>
>
>
> _______________________________________________
>
> GMCnet mailing list
>
> Unsubscribe or Change List Options:
>
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
 
Ken,

the first time I had contact with an Onan it was missing oil, the 2nd
time an Onan didn't fire up was due to not enough fuel. Less than
quarter full or something.

--
Best regards

Peer Oliver Schmidt
PGP Key ID: 0x83E1C2EA

'76a Eleganza II, VA
 
HERE IS DUANES, ANSWER TO THE K1
Issue

http://gmc49ers.blogspot.com/2016/04/onan-start-relay-k1.html

Every gmc, onan user should do this

On Mon, Jan 9, 2017 at 9:16 PM Peer Oliver Schmidt GMC
wrote:

> Ken,
>
>
>
> the first time I had contact with an Onan it was missing oil, the 2nd
>
> time an Onan didn't fire up was due to not enough fuel. Less than
>
> quarter full or something.
>
>
>
> --
>
> Best regards
>
>
>
> Peer Oliver Schmidt
>
> PGP Key ID: 0x83E1C2EA
>
>
>
> '76a Eleganza II, VA
>
>
>
>
>
> _______________________________________________
>
> GMCnet mailing list
>
> Unsubscribe or Change List Options:
>
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
 
WE find that in that case to install a new board as the relay on the board
is not latching.

> I've spent over an hour searching through multiple pages of search results
> with no luck so I will just my question straight out. When I start my
> genset from either switch, it dies as soon as I release the switch. I
> know I've read about this problem before but the only thing I remember was
> it
> will do that if it's low on oil. My is not so I'm left searching for a
> solution.
>
> Anyone?
>
> Thanks,
> Ken
> --
> 1978 Eleganza II
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Also try pumping 9-11.
If that works, order a new board, you can go to our sight and see, or call
other GMC shops.

> WE find that in that case to install a new board as the relay on the board
> is not latching.
>
>
> On Mon, Jan 9, 2017 at 5:54 PM, Ken Harland

>
>> I've spent over an hour searching through multiple pages of search
>> results with no luck so I will just my question straight out. When I start
>> my
>> genset from either switch, it dies as soon as I release the switch. I
>> know I've read about this problem before but the only thing I remember was
>> it
>> will do that if it's low on oil. My is not so I'm left searching for a
>> solution.
>>
>> Anyone?
>>
>> Thanks,
>> Ken
>> --
>> 1978 Eleganza II
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Fremont,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
>

--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Low oil pressure or failure of the relay will create this problem. If jumping 9 to 5 allows the set to run, then the options are the relay isn't
pulling in or the oil pressure switch isn't opening. Follow Duane's suggestions to determine which is the case. If the problem is the relay on the
board, either it isn't getting voltage or the relay itself has failed. If the genset alternator is producing AC, then a measurement across the relay
coil will show voltage or no voltage. If there's voltage but the relay doesn't pull in, replace it. If there's no voltage, start checking components
on the card, or just simply 'shotgun' them.
Check for shorted wires anywhere on the set. I have found the relay armature melted off due to a short in the past.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"The road goes on forever, and the party never ends" --Robert Earl Keen
 
Thanks to all that replied, I'm sure that armed with this tips I'm sure to find my problem. Hopefully will get to it tomorrow.

Ken
--
1978 Eleganza II
 
Thanks again for all the help, here's what I know.

I have oil pressure and the oil pressure switch works fine as does a new one I bought.

Jumping pins 5 & 9 on the control board bypasses several error conditions, not just low oil pressure which is why I now have a spare oil pressure
switch.

The generator doesn't stay running because I don't not have 28 volts on pin 11 which points to a possible voltage regulator issue but not exclusively.
Duane's troubleshooting tips seems to be incomplete as it describes removing and insulating the connectors to it but then it stops there with no
further info on a next step if there is one. Is there a further test of the regulator?
--
1978 Eleganza II
 
I don't think he went into testing the regulator becsuse that is what is being taken out of circuit. The two wires on the "twofer" stay connected
and taped up. Remove spray clean and reseat all the faston terminals as they can be oxidized. Also the solders can be bad on the tabs to the board
from vibration. Pull the board and examine the back side with light and magnifier. 90% of problems can be found here. Also check fuse tabs solder and
clean where the contact fuse. Also be sure fuse is not oversized. Burnt traces can be repaired with jumpers if you are good at bench tech basics.
--
John Lebetski
Woodstock, IL
77 Eleganza II
Source America First
 
Here is the answer
http://gmc49ers.blogspot.com/2015/09/onan-gmc-propane-conversion.html

Replace the alternator with a simple transformer

I will look for a better link

On Mon, Jan 16, 2017 at 7:11 AM John R. Lebetski
wrote:

> I don't think he went into testing the regulator becsuse that is what is
> being taken out of circuit. The two wires on the "twofer" stay connected
>
> and taped up. Remove spray clean and reseat all the faston terminals as
> they can be oxidized. Also the solders can be bad on the tabs to the board
>
> from vibration. Pull the board and examine the back side with light and
> magnifier. 90% of problems can be found here. Also check fuse tabs solder
> and
>
> clean where the contact fuse. Also be sure fuse is not oversized. Burnt
> traces can be repaired with jumpers if you are good at bench tech basics.
>
> --
>
> John Lebetski
>
> Woodstock, IL
>
> 77 Eleganza II
>
> Source America First
>
>
>
> _______________________________________________
>
> GMCnet mailing list
>
> Unsubscribe or Change List Options:
>
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
 
Ken,
Here is the link to the info on the Charger/Alternator Regulator Removal. As John L said it serves not useful purpose and can cause problems with the newer style charger/converters went they are run with the generator.

Go Here:

http://bdub.net/gmcmotorhome.info/generator.html

Gene’s link to the newer propane conversion is not the only good choice to help your onan. The upgrade to the newer electronic ignition is also a very good upgrade to smooth out a rough running generator. It would be my first choice before the expense of the propane conversion and would help the generator run extremely well with propane as the main fuel.

Propane conversion:
http://bdub.net/gmcmotorhome.info/generator.html

Electronic Ignition Conversion:

http://bdub.net/gmcmotorhome.info/generator.html
and
http://www.gmcmhphotos.com/photos/g3608-onan-ignition-upgrade-to-pertronix.html
and
http://www.picturetrail.com/sfx/album/view/1344546

Over the years we have had many upgrade to the systems of our coaches and these are 2 of the many good things designed.

J.R. Wright
GMC GreatLaker
Newsletter Editor/Publisher
Tech Editor
78 Buskirk 30' Stretch
75 Avion Under Reconstruction
Michigan

>
> Here is the answer
> http://gmc49ers.blogspot.com/2015/09/onan-gmc-propane-conversion.html
>
>
> Replace the alternator with a simple transformer
>
> I will look for a better link
>
>
> On Mon, Jan 16, 2017 at 7:11 AM John R. Lebetski

>
>> I don't think he went into testing the regulator because that is what is
>> being taken out of circuit. The two wires on the "twofer" stay connected
>>
>> and taped up. Remove spray clean and reseat all the faston terminals as
>> they can be oxidized. Also the solders can be bad on the tabs to the board
>>
>> from vibration. Pull the board and examine the back side with light and
>> magnifier. 90% of problems can be found here. Also check fuse tabs solder
>> and
>>
>> clean where the contact fuse. Also be sure fuse is not oversized. Burnt
>> traces can be repaired with jumpers if you are good at bench tech basics.
>>
>> --
>>
>> John Lebetski
>>
>> Woodstock, IL
>>
>> 77 Eleganza II
>>
>> Source America First
>>
>>
>>
>> _______________________________________________
>>
>> GMCnet mailing list
>>
>> Unsubscribe or Change List Options:
>>
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
> Thanks again for all the help, here's what I know.
>
> The generator doesn't stay running because I don't not have 28 volts on pin 11 which points to a possible voltage regulator issue but not
> exclusively. Duane's troubleshooting tips seems to be incomplete as it describes removing and insulating the connectors to it but then it stops
> there with no further info on a next step if there is one. Is there a further test of the regulator?

Ken,

It could be, but it is unlikely that the absents of the "run signal" from the flywheel alternator is a regulator issue. Check between pins 8 and 11.
Do you see a 20+VAC there when the unit is running??
If yes, you dodged one bullet.
If no, chase the wires for the two that come out from under the flywheel. Very carefully separate them from their attachments and then test the
alternator winding for continuity.
If there is a winding there (forgotten what resistance it should show, but not a lot) then start looking for the bad connection.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
?

> Here is the answer
> http://gmc49ers.blogspot.com/2015/09/onan-gmc-propane-conversion.html
>
>
> Replace the alternator with a simple transformer
>
> I will look for a better link
>
>
> On Mon, Jan 16, 2017 at 7:11 AM John R. Lebetski

>
> > I don't think he went into testing the regulator becsuse that is what is
> > being taken out of circuit. The two wires on the "twofer" stay connected
> >
> > and taped up. Remove spray clean and reseat all the faston terminals as
> > they can be oxidized. Also the solders can be bad on the tabs to the board
> >
> > from vibration. Pull the board and examine the back side with light and
> > magnifier. 90% of problems can be found here. Also check fuse tabs solder
> > and
> >
> > clean where the contact fuse. Also be sure fuse is not oversized. Burnt
> > traces can be repaired with jumpers if you are good at bench tech basics.
> >
> > --
> >
> > John Lebetski
> >
> > Woodstock, IL
> >
> > 77 Eleganza II
> >
> > Source America First
> >
> >
> >
> > _______________________________________________
> >
> > GMCnet mailing list
> >
> > Unsubscribe or Change List Options:
> >
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
1978 Eleganza II
 
Thanks John,

Can the regulator be tested in any way?

I have done the other items you've suggested and found nothing amiss. I'm going to try Matt's suggestions next.

Ken

> I don't think he went into testing the regulator becsuse that is what is being taken out of circuit. The two wires on the "twofer" stay
> connected and taped up. Remove spray clean and reseat all the faston terminals as they can be oxidized. Also the solders can be bad on the tabs to
> the board from vibration. Pull the board and examine the back side with light and magnifier. 90% of problems can be found here. Also check fuse
> tabs solder and clean where the contact fuse. Also be sure fuse is not oversized. Burnt traces can be repaired with jumpers if you are good at bench
> tech basics.

--
1978 Eleganza II
 
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