Home » Public Forums » GMCnet » [GMCnet] Bringing Onan back to life due to impending hurricane
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #182816 is a reply to message #182733] |
Sat, 01 September 2012 19:26   |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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Senior Member |
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| Robert Mueller wrote on Sat, 01 September 2012 07:10 |
> After looking at the Onan and the manual, where are "pin 5"
> and "pin 9"? Or any other pins for that matter? Page 36 of
> the manual that shows the control board doesn't identify
> anything that looks like that to me. ...
> ... are the pin numbers silkscreened to the board or something?
They are "solder screened" on the board. ...
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On the "repaired" one that has been sitting on my desk for about a year, they ARE silkscreened. I suspect there where a few slight variations over the years.
This might be more info that you need right now, but it isn't bad info for others to know:
Pins 1 to 6 have two terminals each. Across the top of the board, there are one terminal of each "pin", numbered in order, across the top. (This is designed for an easy connection to the remote control panel.) The second terminal of each pin is located down lower, mixed in (almost randomly) with the components of the board. Both terminals of the same numbered pins are "electrically" the same.
Pins 7 and up only have one terminal each and they are also mixed in with the components.
-- now for your answer:
Lower Pin 5 (fuse protected 12v battery power) is next to and just to the left of the lower end of the fuse.
Pin 9 in the middle terminal (of five terminals) across the bottom of the board. Saying it another way, it is the left terminal of the group of three in the lower right of the board.
-- Notes on jumpering the board:
a) Pin 11 is also 12v battery power but is NOT fuse protected. I suggest that it NOT be used while jumpering... just in case.
b) "9 to 5" works ok for troubleshooting, but if you are going to be jumpering the board for actual use, it is very easy to make a mistake and burn something up. Plus it is a hassle to always have to mess with wires and clips every time you want to start and stop the generator.
I would use a very short wire and a female terminal connector to jump pin 9 to the lower terminal of pin 6. (After ensuring that the generator has oil and every thing else it needs.)
Benefits of 6 to 9:
- Jumping these pins (6 & 9) allows the board start and stop switches to operate as normal WITH THE JUMPER LEFT IN PLACE.
- These pins are right next to each other and the cover will fit even with the jumper in place.
- no messing with clips to start and stop the Gen-Set.
For your info: pin 6 is "12v generator running" that is available, but isn't used with the remote. Connecting it to pin 9 powers the ignition and fuel pump and latches one of the relays keeping the above powered until the stop switch is pressed... even if the generator is not running. Yes, it is kind of a safety issue... but so is jumping pins 9 to 5.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #184436 is a reply to message #182848] |
Fri, 14 September 2012 10:21 |
Robin Hood
Messages: 1078
Registered: April 2011
Karma: 3
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Senior Member |
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Tom Phipps came by on Wednesday and we went to the junkyard. We
couldn't find any JC4 vacuum pumps off any big pickups, unfortunately.
We did manage to find some minivans that had the correct electric
wiper motor for the Ken Henderson kit, but we didn't have the correct
tool with us to remove them. We found a total of five second row van
seats with the armrests. We also scored a cruise control module.
Is there a trick to getting those wiper motors out?
Tom looked at my Onan with me. Ether didn't get it to fire. We didn't
see a spark coming off the plug wires, nor did we see any sparks in
the little box containing the points.
I think I should check at night when it's dark. I don't know where my
timing light is; if I could find it, it would tell me if I had spark
or not, yes? Tom suggested I use contact cleaner on the control board
and go wire by wire and clean and resqueeze the terminals.
Jumping pins 9 to 5 makes the solenoid go WHACK!, but the pump doesn't
feel like it's doing anything. Even directly putting current on the
pump doesn't seem to make it do anything.
I've gotten plenty of very good advice already in this thread that I
haven't even tried out yet. :) I'm always open for more, though.
Tom wants me to build a frame to hold the Onan whilst it's worked on.
Mom wants it out of her carport. :)
On 9/1/12, Robin Hood <loxley@gmail.com> wrote:
> Thanks, Mr. Miller. :) This is just for troubleshooting purposes. :)
>
>
> --
> Robin Hood
> Jackson, MS
> 2003 Buick Lesabre
> 1968 Pontiac Catalina
> 1978 GMC Royale motorhome
> 1977 GMC Palm Beach motorhome
>
--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #184459 is a reply to message #184436] |
Fri, 14 September 2012 12:41 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Robin & Tom:
Sorry I didn't get Tom's voice mail until today so I couldn't help y'all
while you were in the junkyard.
The Lumina APV motor, and the wiper arm pivots are all mounted to a tubular
frame which fits under the fiberglass (SMC?) cowling behind the
hood/beneath the dashboard/over the engine. I guess they needed that
elaborate apparatus because of the composite structure.
On early APV's the entire tubular frame had to be removed to get the motor
out. That meant removing the wiper arms and the nuts beneath them, and,
IIRC, a couple of other bolts, to remove the frame. Later, pretty early in
production apparently, the frame was modified so that the motor can be
removed with the frame in place. It's on the right side above the engine
and is secured with 3 cap screws with 10 mm heads. After those are
removed, the motor can be slid sideways and dropped down far enough to
disengage the linkage; you might as well just remove the wiper arm because
I provide a different one. Save the metric nut -- I don't provide those.
Cut the wiring harness at least 12" from the motor connector.
It's a messy job because those engine compartments appear to be sprayed
regularly with used engine oil, but it's not difficult.
Ken H.
On Fri, Sep 14, 2012 at 11:21 AM, Robin Hood <loxley@gmail.com> wrote:
> Tom Phipps came by on Wednesday and we went to the junkyard. We
> couldn't find any JC4 vacuum pumps off any big pickups, unfortunately.
> We did manage to find some minivans that had the correct electric
> wiper motor for the Ken Henderson kit, but we didn't have the correct
> tool with us to remove them. We found a total of five second row van
> seats with the armrests. We also scored a cruise control module.
>
> Is there a trick to getting those wiper motors out?
> ...
>
>
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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] Bringing Onan back to life due to impending hurricane [message #185424 is a reply to message #185417] |
Sat, 22 September 2012 17:20 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Robin, if you look into the top of the coil where the secondary lead goes,
you will see a sharp needle-like projection that goes into the center of
the lead. Onan used real wire back when these units were made. No sir, none
of that graphite impregnated nylon strand crap for them. RFI was not even
in the picture then. They first introduced resistor spark plugs for RFI
problems, and promptly cut plug service life in half, then they introduced
resistor wires, and ignition related service problems went through the
roof. They went away from flywheel magnetos because they didn't produce
enough voltage to overcome resistor crap. Now we have battery coil ignition
with contact breaker points. Not much better. Put on a pertronix solid
state ignition module and end the problems. JWIWD.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Sep 22, 2012 2:32 PM, "John Wright" <powerjon@chartermi.net> wrote:
> Robin of the Hood,
> The picture was very small and hard to see.
>
> Why don't you joint the rest of us on the GMC Photo Site. Doesn't
> cost anything and it is where we store the GMC photo information.
> http://www.gmcmhphotos.com/
> Go to the bottom of the page and sign up for an account.
>
> JR Wright
> 78 Buskirk Stretch
> Michigan
>
>
>
> >
> http://m164.photobucket.com/albumview/albums/goodluckfox/1348348389_zps9654ea85.jpg.html?o=0&newest=1
> >
> > Is that what the spark plug wire is supposed to look like where it
> > plugs
> > into the coil? Because it looks like there's just a few strands of
> > wire
> > that don't connect to nothin.
> >
> > Tester says no spark at the plugs.
> >
> >
> > --
> > Robin Hood
> > Jackson, MS
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #185472 is a reply to message #185424] |
Sun, 23 September 2012 10:30 |
Robin Hood
Messages: 1078
Registered: April 2011
Karma: 3
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Senior Member |
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Ok, so then the wires are *designed* to work like that then? That is,
a sharp needle like projection pokes into the collection of wires at
the center of the spark plug lead. If that's the case, then the wires
are probably good.
If i'm not seeing spark at either the points or at the end of the plug
wires, does that mean the control board is the likely culprit? Or more
likely the various wires. I will take contact wire to the control
board and check the connections on each individual wire.
I am THIS CLOSE to just saying screw it and taking it to the Cummins
dealership and getting them to mess with it.
I wonder how much they'll charge, and how far that would get me
towards a new control board, new wiring harness, and new ignition
system. I can easily seem them just wanting to replace everything till
they got it working. Hell, even *I* could do that, I think.
Argh. How frustrating.
On Sat, Sep 22, 2012 at 5:20 PM, James Hupy <jamesh1296@gmail.com> wrote:
> Robin, if you look into the top of the coil where the secondary lead goes,
> you will see a sharp needle-like projection that goes into the center of
> the lead. Onan used real wire back when these units were made. No sir, none
> of that graphite impregnated nylon strand crap for them. RFI was not even
> in the picture then. They first introduced resistor spark plugs for RFI
> problems, and promptly cut plug service life in half, then they introduced
> resistor wires, and ignition related service problems went through the
> roof. They went away from flywheel magnetos because they didn't produce
> enough voltage to overcome resistor crap. Now we have battery coil ignition
> with contact breaker points. Not much better. Put on a pertronix solid
> state ignition module and end the problems. JWIWD.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
> On Sep 22, 2012 2:32 PM, "John Wright" <powerjon@chartermi.net> wrote:
>
>> Robin of the Hood,
>> The picture was very small and hard to see.
>>
>> Why don't you joint the rest of us on the GMC Photo Site. Doesn't
>> cost anything and it is where we store the GMC photo information.
>> http://www.gmcmhphotos.com/
>> Go to the bottom of the page and sign up for an account.
>>
>> JR Wright
>> 78 Buskirk Stretch
>> Michigan
>>
>>
>>
>> >
>> http://m164.photobucket.com/albumview/albums/goodluckfox/1348348389_zps9654ea85.jpg.html?o=0&newest=1
>> >
>> > Is that what the spark plug wire is supposed to look like where it
>> > plugs
>> > into the coil? Because it looks like there's just a few strands of
>> > wire
>> > that don't connect to nothin.
>> >
>> > Tester says no spark at the plugs.
>> >
>> >
>> > --
>> > Robin Hood
>> > Jackson, MS
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #185477 is a reply to message #185472] |
Sun, 23 September 2012 11:07 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Robin, the control board controls things like low oil level, which would
prevent the engine from running in the event of the engine being low on
oil. This is perhaps the one single biggest cause of no spark that can be
traced to the control board. There is a trick to jumper that part of the
control circuit. I believe terminal 5 and 9 can be jumpered to see if that
is the cause of your no spark. If you jumper those connectors and run the
engine with low oil level, you will damage the engine. Not good in the long
term, but for a test it is ok. Another function of the control board is to
open the fuel system solenoid valve when you attempt to start the
generator. If that function fails, no fuel will flow, and the engine will
not start. A third function of the control board is to apply the electric
choke when starting a cold engine. When the engine is warmed up, the
exhaust manifold heat warms up a thermostatic coil spring that holds the
choke in the open position when starting attempts are made to prevent
overchoking. Both the fuel system solenoid valve and the electric choke can
be jumpered with a 12 volt positive wire to test them, independently of the
control board. If they both prove functional, then this tells you that the
control board has partially failed, and would either need to be repaired or
replaced. I know that replacement control boards are available, both
cummins/onan (think $$$$$$ here) or the dinosaur boards that the GMC
vendors carry. Be advised, if a dinosaur board is fitted to your Onan and
you take it to Cummins/onan for service, they likely will tell you that
they will not work on a Genset that has a non standard control board. If
this does not resolve your no spark situation, it is likely to be the
ignition points. They need to be bright shiney not pitted clean. You can
use your wife's emery board that she uses for her fingernails, followed by
some clean card stock like a business card to absorb any oil or grease that
might be there. That should be enough to get some spark.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Sun, Sep 23, 2012 at 11:30 AM, Robin Hood <loxley@gmail.com> wrote:
> Ok, so then the wires are *designed* to work like that then? That is,
> a sharp needle like projection pokes into the collection of wires at
> the center of the spark plug lead. If that's the case, then the wires
> are probably good.
>
> If i'm not seeing spark at either the points or at the end of the plug
> wires, does that mean the control board is the likely culprit? Or more
> likely the various wires. I will take contact wire to the control
> board and check the connections on each individual wire.
>
> I am THIS CLOSE to just saying screw it and taking it to the Cummins
> dealership and getting them to mess with it.
>
> I wonder how much they'll charge, and how far that would get me
> towards a new control board, new wiring harness, and new ignition
> system. I can easily seem them just wanting to replace everything till
> they got it working. Hell, even *I* could do that, I think.
>
> Argh. How frustrating.
>
>
>
> On Sat, Sep 22, 2012 at 5:20 PM, James Hupy <jamesh1296@gmail.com> wrote:
> > Robin, if you look into the top of the coil where the secondary lead
> goes,
> > you will see a sharp needle-like projection that goes into the center of
> > the lead. Onan used real wire back when these units were made. No sir,
> none
> > of that graphite impregnated nylon strand crap for them. RFI was not even
> > in the picture then. They first introduced resistor spark plugs for RFI
> > problems, and promptly cut plug service life in half, then they
> introduced
> > resistor wires, and ignition related service problems went through the
> > roof. They went away from flywheel magnetos because they didn't produce
> > enough voltage to overcome resistor crap. Now we have battery coil
> ignition
> > with contact breaker points. Not much better. Put on a pertronix solid
> > state ignition module and end the problems. JWIWD.
> > Jim Hupy
> > Salem, Or
> > 78 GMC ROYALE 403
> > On Sep 22, 2012 2:32 PM, "John Wright" <powerjon@chartermi.net> wrote:
> >
> >> Robin of the Hood,
> >> The picture was very small and hard to see.
> >>
> >> Why don't you joint the rest of us on the GMC Photo Site. Doesn't
> >> cost anything and it is where we store the GMC photo information.
> >> http://www.gmcmhphotos.com/
> >> Go to the bottom of the page and sign up for an account.
> >>
> >> JR Wright
> >> 78 Buskirk Stretch
> >> Michigan
> >>
> >>
> >>
> >> >
> >>
> http://m164.photobucket.com/albumview/albums/goodluckfox/1348348389_zps9654ea85.jpg.html?o=0&newest=1
> >> >
> >> > Is that what the spark plug wire is supposed to look like where it
> >> > plugs
> >> > into the coil? Because it looks like there's just a few strands of
> >> > wire
> >> > that don't connect to nothin.
> >> >
> >> > Tester says no spark at the plugs.
> >> >
> >> >
> >> > --
> >> > Robin Hood
> >> > Jackson, MS
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >>
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
>
>
> --
> Robin Hood
> Jackson, MS
> 2003 Buick Lesabre
> 1968 Pontiac Catalina
> 1978 GMC Royale motorhome
> 1977 GMC Palm Beach motorhome
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #185479 is a reply to message #185472] |
Sun, 23 September 2012 11:11 |
Robin Hood
Messages: 1078
Registered: April 2011
Karma: 3
|
Senior Member |
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|
CFO forbids spending money by taking it to the shop. "They're just
going to throw new parts at it AND you'll still have to pay labor. Buy
the parts yourself and we'll put them on together."
I see Jim K. sells the Dinosaur brand Onan control board and a wiring
harness. That will be a good start. I can also clean up the carb
whilst I wait for them to arrive.
I've seen people talk about Pertronix and other ignitions. Jim sells a
"solid state" ignition point system. Hell, for that matter he sells a
new fuel pump to. I need simple and reliable. :) I don't need to try
to fab up or modify.someting to make it work.
Robin
On Sun, Sep 23, 2012 at 10:30 AM, Robin Hood <loxley@gmail.com> wrote:
> Ok, so then the wires are *designed* to work like that then? That is,
> a sharp needle like projection pokes into the collection of wires at
> the center of the spark plug lead. If that's the case, then the wires
> are probably good.
>
> If i'm not seeing spark at either the points or at the end of the plug
> wires, does that mean the control board is the likely culprit? Or more
> likely the various wires. I will take contact wire to the control
> board and check the connections on each individual wire.
>
> I am THIS CLOSE to just saying screw it and taking it to the Cummins
> dealership and getting them to mess with it.
>
> I wonder how much they'll charge, and how far that would get me
> towards a new control board, new wiring harness, and new ignition
> system. I can easily seem them just wanting to replace everything till
> they got it working. Hell, even *I* could do that, I think.
>
> Argh. How frustrating.
>
>
>
> On Sat, Sep 22, 2012 at 5:20 PM, James Hupy <jamesh1296@gmail.com> wrote:
>> Robin, if you look into the top of the coil where the secondary lead goes,
>> you will see a sharp needle-like projection that goes into the center of
>> the lead. Onan used real wire back when these units were made. No sir, none
>> of that graphite impregnated nylon strand crap for them. RFI was not even
>> in the picture then. They first introduced resistor spark plugs for RFI
>> problems, and promptly cut plug service life in half, then they introduced
>> resistor wires, and ignition related service problems went through the
>> roof. They went away from flywheel magnetos because they didn't produce
>> enough voltage to overcome resistor crap. Now we have battery coil ignition
>> with contact breaker points. Not much better. Put on a pertronix solid
>> state ignition module and end the problems. JWIWD.
>> Jim Hupy
>> Salem, Or
>> 78 GMC ROYALE 403
>> On Sep 22, 2012 2:32 PM, "John Wright" <powerjon@chartermi.net> wrote:
>>
>>> Robin of the Hood,
>>> The picture was very small and hard to see.
>>>
>>> Why don't you joint the rest of us on the GMC Photo Site. Doesn't
>>> cost anything and it is where we store the GMC photo information.
>>> http://www.gmcmhphotos.com/
>>> Go to the bottom of the page and sign up for an account.
>>>
>>> JR Wright
>>> 78 Buskirk Stretch
>>> Michigan
>>>
>>>
>>>
>>> >
>>> http://m164.photobucket.com/albumview/albums/goodluckfox/1348348389_zps9654ea85.jpg.html?o=0&newest=1
>>> >
>>> > Is that what the spark plug wire is supposed to look like where it
>>> > plugs
>>> > into the coil? Because it looks like there's just a few strands of
>>> > wire
>>> > that don't connect to nothin.
>>> >
>>> > Tester says no spark at the plugs.
>>> >
>>> >
>>> > --
>>> > Robin Hood
>>> > Jackson, MS
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
>
>
> --
> Robin Hood
> Jackson, MS
> 2003 Buick Lesabre
> 1968 Pontiac Catalina
> 1978 GMC Royale motorhome
> 1977 GMC Palm Beach motorhome
--
Robin Hood
Jackson, MS
2003 Buick Lesabre
1968 Pontiac Catalina
1978 GMC Royale motorhome
1977 GMC Palm Beach motorhome
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #185485 is a reply to message #185479] |
Sun, 23 September 2012 13:20 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
Robin, any replacement ignition system that goes in the original points box
and uses the phenolic resin points plunger to trigger it has the same
Achilles heel as the points do. Asthe engine runs, plunger wears shorter,
and the timing is retarded as a result of the wear. The pertronix module is
triggered by a rotating magnet on the flywheel. No parts come into contact
with each other, ergo no wear takes place, and no degradation of timing
accuracy over time takes place. They either work or they don't. Unaffected
by grease or dirt as well.
Jim Hupy
SALEM,OR
78 GMC Royale 403
On Sep 23, 2012 9:11 AM, "Robin Hood" <loxley@gmail.com> wrote:
> CFO forbids spending money by taking it to the shop. "They're just
> going to throw new parts at it AND you'll still have to pay labor. Buy
> the parts yourself and we'll put them on together."
>
> I see Jim K. sells the Dinosaur brand Onan control board and a wiring
> harness. That will be a good start. I can also clean up the carb
> whilst I wait for them to arrive.
>
> I've seen people talk about Pertronix and other ignitions. Jim sells a
> "solid state" ignition point system. Hell, for that matter he sells a
> new fuel pump to. I need simple and reliable. :) I don't need to try
> to fab up or modify.someting to make it work.
>
> Robin
>
> On Sun, Sep 23, 2012 at 10:30 AM, Robin Hood <loxley@gmail.com> wrote:
> > Ok, so then the wires are *designed* to work like that then? That is,
> > a sharp needle like projection pokes into the collection of wires at
> > the center of the spark plug lead. If that's the case, then the wires
> > are probably good.
> >
> > If i'm not seeing spark at either the points or at the end of the plug
> > wires, does that mean the control board is the likely culprit? Or more
> > likely the various wires. I will take contact wire to the control
> > board and check the connections on each individual wire.
> >
> > I am THIS CLOSE to just saying screw it and taking it to the Cummins
> > dealership and getting them to mess with it.
> >
> > I wonder how much they'll charge, and how far that would get me
> > towards a new control board, new wiring harness, and new ignition
> > system. I can easily seem them just wanting to replace everything till
> > they got it working. Hell, even *I* could do that, I think.
> >
> > Argh. How frustrating.
> >
> >
> >
> > On Sat, Sep 22, 2012 at 5:20 PM, James Hupy <jamesh1296@gmail.com>
> wrote:
> >> Robin, if you look into the top of the coil where the secondary lead
> goes,
> >> you will see a sharp needle-like projection that goes into the center of
> >> the lead. Onan used real wire back when these units were made. No sir,
> none
> >> of that graphite impregnated nylon strand crap for them. RFI was not
> even
> >> in the picture then. They first introduced resistor spark plugs for RFI
> >> problems, and promptly cut plug service life in half, then they
> introduced
> >> resistor wires, and ignition related service problems went through the
> >> roof. They went away from flywheel magnetos because they didn't produce
> >> enough voltage to overcome resistor crap. Now we have battery coil
> ignition
> >> with contact breaker points. Not much better. Put on a pertronix solid
> >> state ignition module and end the problems. JWIWD.
> >> Jim Hupy
> >> Salem, Or
> >> 78 GMC ROYALE 403
> >> On Sep 22, 2012 2:32 PM, "John Wright" <powerjon@chartermi.net> wrote:
> >>
> >>> Robin of the Hood,
> >>> The picture was very small and hard to see.
> >>>
> >>> Why don't you joint the rest of us on the GMC Photo Site. Doesn't
> >>> cost anything and it is where we store the GMC photo information.
> >>> http://www.gmcmhphotos.com/
> >>> Go to the bottom of the page and sign up for an account.
> >>>
> >>> JR Wright
> >>> 78 Buskirk Stretch
> >>> Michigan
> >>>
> >>>
> >>>
> >>> >
> >>>
> http://m164.photobucket.com/albumview/albums/goodluckfox/1348348389_zps9654ea85.jpg.html?o=0&newest=1
> >>> >
> >>> > Is that what the spark plug wire is supposed to look like where it
> >>> > plugs
> >>> > into the coil? Because it looks like there's just a few strands of
> >>> > wire
> >>> > that don't connect to nothin.
> >>> >
> >>> > Tester says no spark at the plugs.
> >>> >
> >>> >
> >>> > --
> >>> > Robin Hood
> >>> > Jackson, MS
> >>> _______________________________________________
> >>> GMCnet mailing list
> >>> Unsubscribe or Change List Options:
> >>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >>>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >
> >
> >
> > --
> > Robin Hood
> > Jackson, MS
> > 2003 Buick Lesabre
> > 1968 Pontiac Catalina
> > 1978 GMC Royale motorhome
> > 1977 GMC Palm Beach motorhome
>
>
>
> --
> Robin Hood
> Jackson, MS
> 2003 Buick Lesabre
> 1968 Pontiac Catalina
> 1978 GMC Royale motorhome
> 1977 GMC Palm Beach motorhome
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #185491 is a reply to message #185485] |
Sun, 23 September 2012 15:55 |
|
mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
|
Senior Member |
|
|
The way I understand it: The points do not have the spring tension to keep the plunger from "binding" a little as it slides up and down. Unlike the valves and lifters, the points system isn't designed to have the pressure needed. the result is erratic timing. You can see this my watching the stock system with a timing light.
SO... any replacement system that uses the plunger will have erratic timing. This is the reason Onan had "de-tuned" the timing, running it more "retarded" than the "best" timing for performance and efficiency. A system triggering off of the flywheel by-passes the plunger, allowing much more aggressive timing... safely.
Robin, do NOT just buy new parts and throw it at the Onan. Jumping the board takes it out of the loop, so until you get it running with the board jumped... A NEW BOARD WILL NOT HELP.
Logical troubleshooting steps can be in a separate message.
| James Hupy wrote on Sun, 23 September 2012 11:20 |
Robin, any replacement ignition system that goes in the original points box
and uses the phenolic resin points plunger to trigger it has the same
Achilles heel as the points do. Asthe engine runs, plunger wears shorter...
> CFO forbids spending money by taking it to the shop. "They're
> just going to throw new parts at it AND you'll still have to
> pay labor. Buy the parts yourself and we'll put them on
> together."
>
> I see Jim K. sells the Dinosaur brand Onan control board ...
> ...
> > Argh. How frustrating.
|
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #185502 is a reply to message #185499] |
Sun, 23 September 2012 18:04 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
Robin, you can jumper from a known 12 volt positive power source to the
positive wire on the ignition coil, and immediately crank the engine. You
should have spark at the plug leads. If no spark, then it is points,
condenser, or coil. Be sure to remove the positive lead from the control
board to the coil for this test.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Sep 23, 2012 3:45 PM, "Robin Hood" <loxley@gmail.com> wrote:
> I didn't realize that there was a way to completely bypass the control
> board (that does several important things so obviously one should only
> bypass for troubleshooting reasons). So how does one bypass the board
> completely? I need to see if I can narrow down the cause of my
> no-spark condition.
>
> All I've seen so far is that 9to5 runs the pump. But the ignition
> system also needs juice.
>
>
> On Sun, Sep 23, 2012 at 3:55 PM, Mike Miller <m000035@gmail.com> wrote:
>
> (snip)
> >
> > Robin, do NOT just buy new parts and throw it at the Onan. Jumping the
> board takes it out of the loop, so until you get it running with the board
> jumped... A NEW BOARD WILL NOT HELP.
> >
> > Logical troubleshooting steps can be in a separate message.
> >
>
> --
> Robin Hood
> Jackson, MS
> 2003 Buick Lesabre
> 1968 Pontiac Catalina
> 1978 GMC Royale motorhome
> 1977 GMC Palm Beach motorhome
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] Bringing Onan back to life due to impending hurricane [message #185524 is a reply to message #185499] |
Sun, 23 September 2012 22:03 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Robin,
Jumping 5 to 9 completely bypasses the control board and provides power to
the ignition coil, the fuel solenoid, and the fuel pump. So you need no
other jumper to get the engine running -- IF everything up to the control
board is correct. So, before you jump 5 to 9, connect a test lamp from 9
(or the terminal on the ignition coil to which 9 is connected) to ground.
If that lamp illuminates when 5 is connected to 9, all up to there is OK
for your testing -- you can remove the lamp.
You may find the diagram here easier to follow than those in the manual.
Ignore the label "4 kW" -- 6 kW is identical; there are other minor
changes to match the Onan I had at the time, but they should confuse most
issues.
http://www.gmcmhphotos.com/photos/data/5813/KH_Onan_Wiring1.pdf
or
http://goo.gl/lS09C
The only really essential function of the control board is to monitor oil
pressure. Its other major function is to ensure that you don't engage the
starter when the engine's running; if you can't handle that chore yourself,
I'm afraid we can't help you.
As others have said, don't waste good money on exorbitant Cummins service
charges, nor on parts which you don't need or may be sub-optimal (such as
any ignition upgrade other than Pertronix). The Onan is too simple a
device to let it throw you -- yet. (One must remember that I finally gave
up on Onan, but not because there was ever anything on it I couldn't fix.)
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Sun, Sep 23, 2012 at 6:45 PM, Robin Hood wrote:
> I didn't realize that there was a way to completely bypass the control
> board (that does several important things so obviously one should only
> bypass for troubleshooting reasons). So how does one bypass the board
> completely? I need to see if I can narrow down the cause of my
> no-spark condition.
>
> All I've seen so far is that 9to5 runs the pump. But the ignition
> system also needs juice.
>
>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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