Home » Public Forums » GMCnet » [GMCnet] Onan doesn't want to run when GMC is rolling
| [GMCnet] Onan doesn't want to run when GMC is rolling [message #89670] |
Wed, 23 June 2010 22:24  |
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I have a silly issue. Silly and doesnšt make sense to me.
I can run the Onan sitting still. If I start the GMC (403) it coughs and
cuts out. It can, at times, be restarted and itšll run for a few minutes if
restarting is successful. Since it hot in Kentucky right now, having it work
correctly would be a plus. Though I have a 78, the dash air won't make up
for 90 degrees and 90 percent humidity.
As an aside, the mixed gasoline sure hates the QuadraJet and warm weather,
too. Getting on the interstate is a crap shoot. I pray no one is coming up
fast and while also praying it accepts the fact that it's hot and that gas
isn't what it used to be in 1978.
Byron Songer
1978 Royale by Coachmen (the puller)
1997 SOB (the pusher)
Louisville, KY
Personal - http://web.me.com/bnsonger
Eastern States - http://www.gmceast.com
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--
Byron Songer
Full-timing to enjoy the USA
Former owner but still an admirer
GMC paint schemes at -
http://www.songerconsulting.net
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| Re: [GMCnet] Onan doesn't want to run when GMC is rolling [message #89674 is a reply to message #89670] |
Wed, 23 June 2010 22:34  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Byron,
Remember that Coachmen did not drop the fuel tanks to attach the Onan to the
rear tank's dedicated fuel pickup. Instead, they put a Tee in the main tank
fuel line. I'll bet the 455's pump is starving the Onan. Try running from
the Aux tank as a test.
The second problem and the first may even be related.
Solution? ???
Ken H.
On Wed, Jun 23, 2010 at 11:24 PM, Byron Songer <bsonger@songerconsulting.net
> wrote:
> I have a silly issue. Silly and doesnšt make sense to me.
>
> I can run the Onan sitting still. If I start the GMC (403) it coughs and
> cuts out. It can, at times, be restarted and itšll run for a few minutes if
> restarting is successful. Since it hot in Kentucky right now, having it
> work
> correctly would be a plus. Though I have a 78, the dash air won't make up
> for 90 degrees and 90 percent humidity.
>
> As an aside, the mixed gasoline sure hates the QuadraJet and warm weather,
> too. Getting on the interstate is a crap shoot. I pray no one is coming up
> fast and while also praying it accepts the fact that it's hot and that gas
> isn't what it used to be in 1978.
>
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Onan doesn't want to run when GMC is rolling [message #89675 is a reply to message #89670] |
Wed, 23 June 2010 22:35 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Your problem is from the fuel line that is shared by both the engine and the
generator.Coachman loved to do it that way, but presents a problem on some.
Hook up the Gen to the back tank at the fitting that the standard units use.
AS for the high temp creating a problem; do you have a aux. fuel pump by the
rear tank?
On Wed, Jun 23, 2010 at 8:24 PM, Byron Songer
<bsonger@songerconsulting.net>wrote:
> I have a silly issue. Silly and doesnšt make sense to me.
>
> I can run the Onan sitting still. If I start the GMC (403) it coughs and
> cuts out. It can, at times, be restarted and itšll run for a few minutes if
> restarting is successful. Since it hot in Kentucky right now, having it
> work
> correctly would be a plus. Though I have a 78, the dash air won't make up
> for 90 degrees and 90 percent humidity.
>
> As an aside, the mixed gasoline sure hates the QuadraJet and warm weather,
> too. Getting on the interstate is a crap shoot. I pray no one is coming up
> fast and while also praying it accepts the fact that it's hot and that gas
> isn't what it used to be in 1978.
>
> Byron Songer
> 1978 Royale by Coachmen (the puller)
> 1997 SOB (the pusher)
> Louisville, KY
> Personal - http://web.me.com/bnsonger
> Eastern States - http://www.gmceast.com
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
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List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Onan doesn't want to run when GMC is rolling [message #89683 is a reply to message #89674] |
Thu, 24 June 2010 07:27 |
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Jim and Ken,
Coachmen did it again! How many more secrets to go? Only The Shadow knows.
I wouldn't think that ten degrees in temp would make that much of a
difference. When it's cooler the genset and engine work together well.
I don't have an extra fuel pump. That's for the next owner to tinker with.
Oddly, the tanks were dropped and new lines installed by a company in
Orlando about twelve years ago when Silver Lady had another owner. It would
have been an excellent time to correct a Coachmen shortcut.
Thanks for the excellent response.
Byron
Jim Kanomata wrote:
> Your problem is from the fuel line that is shared by both the engine and
> the
generator. Coachman loved to do it that way, but presents a problem on
> some.
Hook up the Gen to the back tank at the fitting that the standard units
> use.
AS for the high temp creating a problem; do you have a aux. fuel pump by
> the
rear tank?
Ken Henderson wrote:
> Byron,
>
> Remember that Coachmen did not drop the fuel tanks to attach the Onan to the
> rear tank's dedicated fuel pickup. Instead, they put a Tee in the main tank
> fuel line. I'll bet the 455's pump is starving the Onan. Try running from
> the Aux tank as a test.
>
> The second problem and the first may even be related.
>
> Solution? ???
>
> Ken H.
>
>
> On Wed, Jun 23, 2010 at 11:24 PM, Byron Songer <bsonger@songerconsulting.net
>> wrote:
>
>> I have a silly issue. Silly and doesnšt make sense to me.
>>
>> I can run the Onan sitting still. If I start the GMC (403) it coughs and
>> cuts out. It can, at times, be restarted and itšll run for a few minutes if
>> restarting is successful. Since it hot in Kentucky right now, having it
>> work
>> correctly would be a plus. Though I have a 78, the dash air won't make up
>> for 90 degrees and 90 percent humidity.
>>
>> As an aside, the mixed gasoline sure hates the QuadraJet and warm weather,
>> too. Getting on the interstate is a crap shoot. I pray no one is coming up
>> fast and while also praying it accepts the fact that it's hot and that gas
>> isn't what it used to be in 1978.
>>
>>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
--
Byron Songer
Full-timing to enjoy the USA
Former owner but still an admirer
GMC paint schemes at -
http://www.songerconsulting.net
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| Re: [GMCnet] Onan doesn't want to run when GMC is rolling [message #89754 is a reply to message #89670] |
Thu, 24 June 2010 18:13 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| Byron Songer wrote on Wed, 23 June 2010 23:24 |
I have a silly issue. Silly and doesnšt make sense to me.
I can run the Onan sitting still. If I start the GMC (403) it coughs and cuts out. It can, at times, be restarted and itšll run for a few minutes if restarting is successful. Since it hot in Kentucky right now, having it work correctly would be a plus. Though I have a 78, the dash air won't make up for 90 degrees and 90 percent humidity.
As an aside, the mixed gasoline sure hates the QuadraJet and warm weather, too. Getting on the interstate is a crap shoot. I pray no one is coming up fast and while also praying it accepts the fact that it's hot and that gas isn't what it used to be in 1978.
Byron Songer
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Bryon,
I have a cheap trick that you should try before you do much else (like spend money).
Set the selector to AUX and do a low pressure compressed air blow into the APU (Onan) fuel line. This will TEMPorarily clear the the pick up sock. If the problem goes away, sell the coach and play dumb (some people are good at that, but you may have to work at it).
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Onan doesn't want to run when GMC is rolling [message #89897 is a reply to message #89670] |
Fri, 25 June 2010 17:27 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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""I have a silly issue. Silly and doesnšt make sense to me.
I can run the Onan sitting still. If I start the GMC (403) it coughs and
cuts out. It can, at times, be restarted and itšll run for a few minutes if
restarting is successful. Since it hot in Kentucky right now, having it work
correctly would be a plus. Though I have a 78, the dash air won't make up
for 90 degrees and 90 percent humidity""
If it runs with the 403 at idle, but stops while underway, make sure the Onan oil level is at the very top--As you accelerate or turn corners, it will shut off due to low oil pressue if it is even slightly below full.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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