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[GMCnet] Engine starts when cold, won't crank when warm [message #307238] Fri, 16 September 2016 19:00 Go to next message
David Gardner is currently offline  David Gardner   United States
Messages: 62
Registered: June 2014
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Member
Haven’t posted in a while, but I have one that has me stumped, and could use some advice..
My engine starts when cold. When the engine is warm and I turn the engine off and then try to restart it, it acts like the battery is nearly dead. I’ve had the batteries checked at two locations and both say the batteries are good. Once the engine is completely cold, the coach starts just fine.
I recently had both the alternator and starter replaced thinking they were part of the problem (they need replacing anyway) but that did not solve the problem.
After stopping with the engine not running I get a 12 volt reading from the battery, and while the engine is running I get a14.5 reading at the battery, so it appears that the batteries are charging while the engine is running
Coach runs fine until I stop, then it barely cranks over, until it is cold again several hours later.
thanking everyone in advance for your thoughts.

David Gardner
1976 Birchaven (455 motor)
Oxnard Ca


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Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307239 is a reply to message #307238] Fri, 16 September 2016 19:16 Go to previous messageGo to next message
77Royale   United States
Messages: 461
Registered: June 2014
Location: Mid Michigan
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Senior Member
Does engaging the boost switch do anything or make any difference with the hard crank condition?

Possibly a bad cable or ground. Sounds like everything else was replaced already.


77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy. Mid Michigan
Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307240 is a reply to message #307239] Fri, 16 September 2016 19:21 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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Registered: May 2010
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Senior Member
Simple answer, battery cables and grounds. Feel the cables with your bare
hands. Any hot ones, investigate further.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Sep 16, 2016 5:17 PM, "Wayne Rogewski" wrote:

> Does engaging the boost switch do anything or make any difference with the
> hard crank condition?
>
> Possibly a bad cable or ground. Sounds like everything else was replaced
> already.
> --
> 77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson
> carb and dizzy.
> Mid Michigan
>
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Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307241 is a reply to message #307238] Fri, 16 September 2016 19:30 Go to previous messageGo to next message
Scott Nutter is currently offline  Scott Nutter   United States
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Location: Houston/San Diego
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Senior Member
I had the same problem.
I put on a new starter, and increased the gauge of wire to the starter. Both negative and positive.
That cured the problem. It seems to be a fairly common problem.
Scott


Scott Nutter 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI Houston, Texas
Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307242 is a reply to message #307238] Fri, 16 September 2016 19:38 Go to previous messageGo to next message
A Hamilto is currently offline  A Hamilto   United States
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Senior Member
David Gardner wrote on Fri, 16 September 2016 19:00
Haven't posted in a while, but I have one that has me stumped, and could use some advice..
My engine starts when cold. When the engine is warm and I turn the engine off and then try to restart it, it acts like the battery is nearly dead. I've had the batteries checked at two locations and both say the batteries are good. Once the engine is completely cold, the coach starts just fine.
I recently had both the alternator and starter replaced thinking they were part of the problem (they need replacing anyway) but that did not solve the problem.
After stopping with the engine not running I get a 12 volt reading from the battery, and while the engine is running I get a14.5 reading at the battery, so it appears that the batteries are charging while the engine is running
Coach runs fine until I stop, then it barely cranks over, until it is cold again several hours later.
thanking everyone in advance for your thoughts.

David Gardner
1976 Birchaven (455 motor)
Oxnard Ca
http://www.gmcmhphotos.com/photos/gmc-cranking-improve-for-free/p34367-hot-start-problem-2c-battery-2f-starter.html
Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307245 is a reply to message #307238] Fri, 16 September 2016 20:02 Go to previous messageGo to next message
bdub is currently offline  bdub   United States
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Registered: February 2004
Location: Central Texas
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Senior Member

Before ya turn the distributor, make sure that the mechanical advance
flyweights aren't frozen in the extended position.

On Fri, Sep 16, 2016 at 7:58 PM, Billy Massey wrote:

> Ya might try retarding the timing just a bit.
>
> On Fri, Sep 16, 2016 at 7:00 PM, David Gardner wrote:
>
>> Haven’t posted in a while, but I have one that has me stumped, and could
>> use some advice..
>> My engine starts when cold. When the engine is warm and I turn the
>> engine off and then try to restart it, it acts like the battery is nearly
>> dead. I’ve had the batteries checked at two locations and both say the
>> batteries are good. Once the engine is completely cold, the coach starts
>> just fine.
>>
>
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bdub
'76 Palm Beach/Central Texas
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Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307246 is a reply to message #307238] Fri, 16 September 2016 19:58 Go to previous messageGo to next message
bdub is currently offline  bdub   United States
Messages: 1578
Registered: February 2004
Location: Central Texas
Karma: 5
Senior Member

Ya might try retarding the timing just a bit.

On Fri, Sep 16, 2016 at 7:00 PM, David Gardner wrote:

> Haven’t posted in a while, but I have one that has me stumped, and could
> use some advice..
> My engine starts when cold. When the engine is warm and I turn the engine
> off and then try to restart it, it acts like the battery is nearly dead.
> I’ve had the batteries checked at two locations and both say the batteries
> are good. Once the engine is completely cold, the coach starts just fine.
> I recently had both the alternator and starter replaced thinking they were
> part of the problem (they need replacing anyway) but that did not solve the
> problem.
> After stopping with the engine not running I get a 12 volt reading from
> the battery, and while the engine is running I get a14.5 reading at the
> battery, so it appears that the batteries are charging while the engine is
> running
> Coach runs fine until I stop, then it barely cranks over, until it is cold
> again several hours later.
> thanking everyone in advance for your thoughts.
>
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bdub
'76 Palm Beach/Central Texas
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www.gmcmhregistry.com
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Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307250 is a reply to message #307246] Fri, 16 September 2016 21:04 Go to previous messageGo to next message
<diego.hotrod is currently offline  <diego.hotrod   United States
Messages: 7
Registered: September 2016
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Junior Member
Replace the battery. Your measurements tells it all. A good battery should read about 13.2 volts. The fact that you read 12 after the engine is shut off is key. The 14.5 volts while engine is running indicates the charging system is fine. Poor cables or bad connections may be an issue as a warm start may over heat battery connections. Then consider the ignition timing. If it is advanced (correctly or incorrectly set) a warm engine may actually be harder to start than when cold. My experience says replace the battery. Question: will it start in boost position? If so then you must have a bad battery or possibly an undersized one or bad cable/connection somewhere.

Good luck

Rod cruzin in South Cali

From: Billy Massey
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Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307253 is a reply to message #307250] Fri, 16 September 2016 21:58 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Location: S.E. Michigan
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Senior Member
I will start by saying that this is exactly the symptoms my coach had before I discovered that the started was toast about 10K miles back. (He got it down, cracked the back plate off and said,"Oh God - That's not fixing here!")

Now -
While we are at it, a good battery at rest should read 12.6 with some load. Maybe 12.7 with zero load. If you don't see that, first go to a car parts store and check your meter on a new battery on the shelf. Then, get an new battery. but the hot/cold is so reminiscent of my starter failure, that I think that you should look there when you don't find some other answer. A starter is the only heavy spare part I carry. There is a reason.

A 10MT starter is so robust that it was used from 1956 to the late 90s. The problem is that it is Too Robust. It will keep trying when it should have quit and gone home long before. Then the is the problem that the 10MT for the TH425 went out of production 38 years ago. You can get a rebuilt, but don't expect it to be in anybody X-stock list. If you haven't looked into your starter recently, think about it. Changing brushes is cheap and easy.

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
Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307285 is a reply to message #307253] Sat, 17 September 2016 14:51 Go to previous messageGo to next message
KB is currently offline  KB   United States
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Registered: September 2009
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Senior Member
Any suggestions on a good rebuild kit (or what should be in such a kit)?
Seems like cheap insurance and lighter/cheaper than carrying around a whole spare starter.
Might not always be able to fix it, but a rebuild kit could keep you from being stranded
(or you could just do a pre-emptive rebuild with it).

thanks,
Karen
1975 26'


Matt Colie wrote on Fri, 16 September 2016 19:58

A 10MT starter is so robust that it was used from 1956 to the late 90s. The problem is that it is Too Robust. It will keep trying when it should have quit and gone home long before. Then the is the problem that the 10MT for the TH425 went out of production 38 years ago. You can get a rebuilt, but don't expect it to be in anybody X-stock list. If you haven't looked into your starter recently, think about it. Changing brushes is cheap and easy.


Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307286 is a reply to message #307285] Sat, 17 September 2016 15:07 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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Registered: May 2010
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Senior Member
Most of the starter failures can be traced to the solenoid contactor disc.
It no longer is solid copper, but a cheap substitute that has a thin copper
foil like coating that will not handle the amperage loads of the starter.
It arcs off a bit of the foil coating with each use. It is staked on to the
solenoid plunger and is difficult to remove and reverse like the solid disc
can. So, definitely, the solenoid should be included in your spare parts.
Thrust washers, and brushes, as well as the bushing in the nose casting.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Sep 17, 2016 12:52 PM, "KB" wrote:

> Any suggestions on a good rebuild kit (or what should be in such a kit)?
> Seems like cheap insurance and lighter/cheaper than carrying around a
> whole spare starter.
> Might not always be able to fix it, but a rebuild kit could keep you from
> being stranded
> (or you could just do a pre-emptive rebuild with it).
>
> thanks,
> Karen
> 1975 26'
>
>
> Matt Colie wrote on Fri, 16 September 2016 19:58
>> A 10MT starter is so robust that it was used from 1956 to the late 90s.
> The problem is that it is Too Robust. It will keep trying when it should
>> have quit and gone home long before. Then the is the problem that the
> 10MT for the TH425 went out of production 38 years ago. You can get a
>> rebuilt, but don't expect it to be in anybody X-stock list. If you
> haven't looked into your starter recently, think about it. Changing
> brushes is
>> cheap and easy.
>
>
>
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Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307291 is a reply to message #307285] Sat, 17 September 2016 15:13 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
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Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
When we removed Lou Boone's transmission two weeks ago for Manny to rebuild
it here, we broke the starter. Cracked the bakelite housing which supports
the primary 12VDC connection. Rather than fool with tearing down one of
the old starters laying around here for a replacement housing, we took it
to the local Carb/Ignition shop. Charlie Smith, the owner, is about 65.
He started work at 17 for one of my grandfather's best friends. He now
owns the shop, piled high with old carbs, starters, generators and
alternators. He won't touch a fuel injected car, 'tho' he does do diesel
mechanical fuel injection.

We took Lou's starter to him on Thursday afternoon: "Charlie, is there any
way you can possibly get this fixed by quitting time tomorrow so we can
install it over the weekend?" "Aw man, I'm so busy, NO WAY! ... OK, have
my wife check it in and I'll see what I can do -- but don't count on it."

On the way home from lunch, we stopped at Charlie's to pick up the starter,
fixed or not. What we found was a shiny new-looking one. "It was in
pretty good shape, brushes looked real good. But one armature bushing was
worn so I replaced it. Found a near-new switch housing on an old starter.
It should work OK now..." Total bill? $22.00. :-) Good Ol' Charlie!

Ken H.


Matt Colie wrote on Fri, 16 September 2016 19:58
>> A 10MT starter is so robust that it was used from 1956 to the late 90s.
> The problem is that it is Too Robust. It will keep trying when it should
>> have quit and gone home long before. Then the is the problem that the
> 10MT for the TH425 went out of production 38 years ago. You can get a
>> rebuilt, but don't expect it to be in anybody X-stock list. If you
> haven't looked into your starter recently, think about it. Changing
> brushes is
>> cheap and easy.
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307302 is a reply to message #307285] Sat, 17 September 2016 18:45 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
Senior Member
KB wrote on Sat, 17 September 2016 15:51
Any suggestions on a good rebuild kit (or what should be in such a kit)?
Seems like cheap insurance and lighter/cheaper than carrying around a whole spare starter.
Might not always be able to fix it, but a rebuild kit could keep you from being stranded (or you could just do a pre-emptive rebuild with it).

thanks,
Karen
1975 26'

Karen,

The pre-emptive rebuild is really the good idea.
If you had a set of brushes and screws for same, you could probably bring a dead starter back to life.
But,
Of the two that I have seen that failed in service, they really needed the commutator trued (takes a lathe) and the front bushing changed out.
(One of those was mine and it was Sunday afternoon in BF Egypt.)

If you were wondering, the life seems to be about that of a 455 *1.25. So the simple answer would be, if you have the engine out, rebuild the starter while all you have to do is pick it off the floor. If you are doing anything that requires getting the starter down, three little fasteners and the back plate gets open. Look inside and see how much brush is left. If the brush arm is within 1/16 of the commutator, think about getting that taken care of before it goes back in.

My starter that I have is fresh. I carry the known good used starter just in case some friend needs 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
Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307303 is a reply to message #307291] Sat, 17 September 2016 18:52 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
Senior Member
Ken Henderson wrote on Sat, 17 September 2016 16:13
When we removed Lou Boone's transmission two weeks ago for Manny to rebuild
it here, we broke the starter. Cracked the bakelite housing which supports the primary 12VDC connection. Rather than fool with tearing down one of
the old starters laying around here for a replacement housing, we took it to the local Carb/Ignition shop. Charlie Smith, the owner, is about 65.
He started work at 17 for one of my grandfather's best friends.
<snip>
On the way home from lunch, we stopped at Charlie's to pick up the starter, fixed or not. What we found was a shiny new-looking one. "It was in
pretty good shape, brushes looked real good. But one armature bushing was worn so I replaced it. Found a near-new switch housing on an old starter.
It should work OK now..." Total bill? $22.00. Smile Good Ol' Charlie!

Ken H.

Ken,

I think you know how lucky you are to have Charlie around.
I just lost my best local shop to a strip mall and the second choice shop is getting kind of shabby looking and he can't even keep a kid to do the grunt work. I give him one - maybe two years more.

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
Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307308 is a reply to message #307238] Sat, 17 September 2016 20:17 Go to previous messageGo to next message
jhbridges is currently offline  jhbridges   United States
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
Senior Member
Dollar Carburetor and Electric in Gainesville, GA. "Here's the brush kit and nose bushing, I'll have the module after 7 tomorrow morning. 19 bux for the parts. Works like a new one.

--johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
Re: [GMCnet] Engine starts when cold, won't crank when warm [message #307317 is a reply to message #307238] Sun, 18 September 2016 01:58 Go to previous messageGo to next message
Mr ERFisher is currently offline  Mr ERFisher   United States
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Registered: August 2005
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Read here
http://www.gmcmhphotos.com/photos/g5493-gmc-cranking-improve-for-free.html



On Friday, September 16, 2016, David Gardner wrote:

> Haven’t posted in a while, but I have one that has me stumped, and could
> use some advice..
> My engine starts when cold. When the engine is warm and I turn the engine
> off and then try to restart it, it acts like the battery is nearly dead.
> I’ve had the batteries checked at two locations and both say the batteries
> are good. Once the engine is completely cold, the coach starts just fine.
> I recently had both the alternator and starter replaced thinking they were
> part of the problem (they need replacing anyway) but that did not solve the
> problem.
> After stopping with the engine not running I get a 12 volt reading from
> the battery, and while the engine is running I get a14.5 reading at the
> battery, so it appears that the batteries are charging while the engine is
> running
> Coach runs fine until I stop, then it barely cranks over, until it is cold
> again several hours later.
> thanking everyone in advance for your thoughts.
>
> David Gardner
> 1976 Birchaven (455 motor)
> Oxnard Ca
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>


--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
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Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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Re: [GMCnet] (UPDATE)Engine starts when cold, won't crank when warm [message #307356 is a reply to message #307238] Sun, 18 September 2016 18:53 Go to previous messageGo to next message
David Gardner is currently offline  David Gardner   United States
Messages: 62
Registered: June 2014
Karma: 0
Member
Thanks to all for your suggestions. They were all greatly appreciated. I have checked all my battery connections, and everything looks good.
Both my batteries have been checked by two different battery stores, and they say the batteries are good.

I have just noticed that when I put my key into the ignition, and depress it slightly, I get a buzz from the battery isolator. Is this normal?

Over the last few days the coach has gone from starting when cold, to barely starting at all, to now not starting at all.
I checked and I do have voltage (12.5) going down the starter.
At the moment I am only getting a click when I turn the key to start the engine. Batteries are still showing 12.5 volts when I check the battery with the volt meter.


> On Sep 16, 2016, at 5:00 PM, David Gardner wrote:
>
> Haven’t posted in a while, but I have one that has me stumped, and could use some advice..
> My engine starts when cold. When the engine is warm and I turn the engine off and then try to restart it, it acts like the battery is nearly dead. I’ve had the batteries checked at two locations and both say the batteries are good. Once the engine is completely cold, the coach starts just fine.
> I recently had both the alternator and starter replaced thinking they were part of the problem (they need replacing anyway) but that did not solve the problem.
> After stopping with the engine not running I get a 12 volt reading from the battery, and while the engine is running I get a14.5 reading at the battery, so it appears that the batteries are charging while the engine is running
> Coach runs fine until I stop, then it barely cranks over, until it is cold again several hours later.
> thanking everyone in advance for your thoughts.
>
> David Gardner
> 1976 Birchaven (455 motor)
> Oxnard Ca
>


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Re: [GMCnet] (UPDATE)Engine starts when cold, won't crank when warm [message #307358 is a reply to message #307356] Sun, 18 September 2016 18:57 Go to previous messageGo to next message
sgltrac is currently offline  sgltrac   United States
Messages: 2797
Registered: April 2011
Karma: 1
Senior Member
Ignition switch.

Sully
77 eleganza 2
Seattle

On Sunday, September 18, 2016, David Gardner wrote:

> Thanks to all for your suggestions. They were all greatly appreciated. I
> have checked all my battery connections, and everything looks good.
> Both my batteries have been checked by two different battery stores, and
> they say the batteries are good.
>
> I have just noticed that when I put my key into the ignition, and depress
> it slightly, I get a buzz from the battery isolator. Is this normal?
>
> Over the last few days the coach has gone from starting when cold, to
> barely starting at all, to now not starting at all.
> I checked and I do have voltage (12.5) going down the starter.
> At the moment I am only getting a click when I turn the key to start the
> engine. Batteries are still showing 12.5 volts when I check the battery
> with the volt meter.
>
>
>> On Sep 16, 2016, at 5:00 PM, David Gardner > wrote:
>>
>> Haven’t posted in a while, but I have one that has me stumped, and could
> use some advice..
>> My engine starts when cold. When the engine is warm and I turn the
> engine off and then try to restart it, it acts like the battery is nearly
> dead. I’ve had the batteries checked at two locations and both say the
> batteries are good. Once the engine is completely cold, the coach starts
> just fine.
>> I recently had both the alternator and starter replaced thinking they
> were part of the problem (they need replacing anyway) but that did not
> solve the problem.
>> After stopping with the engine not running I get a 12 volt reading from
> the battery, and while the engine is running I get a14.5 reading at the
> battery, so it appears that the batteries are charging while the engine is
> running
>> Coach runs fine until I stop, then it barely cranks over, until it is
> cold again several hours later.
>> thanking everyone in advance for your thoughts.
>>
>> David Gardner
>> 1976 Birchaven (455 motor)
>> Oxnard Ca
>>
>
>
> _______________________________________________
> GMCnet mailing list
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Sully 77 Royale basket case. Future motorhome land speed record holder(bucket list) Seattle, Wa.
Re: [GMCnet] (UPDATE)Engine starts when cold, won't crank when warm [message #307361 is a reply to message #307356] Sun, 18 September 2016 19:43 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
David,

When you say you have 12.5 VDC at the starter, is that with the starter
activated? Otherwise, it's a virtually meaningless number. It's the
voltage under load that's important, and it must be measured at the battery
cable BOLT on the starter -- NOT at the cable end.

I've seen two instances within the past 6 months, one of them my own, where
similar problems were due to battery cables which were apparently good, but
the end terminals did not make perfect contact with the cable itself. In
one instance, there was smoke from the terminal while cranking. The other
terminal pulled off under severe manual twisting -- revealing severe
corrosion. New cables cured both problems.

Ken H.


On Sun, Sep 18, 2016 at 7:53 PM, David Gardner wrote:

> Thanks to all for your suggestions. They were all greatly appreciated. I
> have checked all my battery connections, and everything looks good.
> Both my batteries have been checked by two different battery stores, and
> they say the batteries are good.
>
> I have just noticed that when I put my key into the ignition, and depress
> it slightly, I get a buzz from the battery isolator. Is this normal?
>
> Over the last few days the coach has gone from starting when cold, to
> barely starting at all, to now not starting at all.
> I checked and I do have voltage (12.5) going down the starter.
> At the moment I am only getting a click when I turn the key to start the
> engine. Batteries are still showing 12.5 volts when I check the battery
> with the volt meter.
>
>
>> On Sep 16, 2016, at 5:00 PM, David Gardner wrote:
>>
>> Haven’t posted in a while, but I have one that has me stumped, and could
> use some advice..
>> My engine starts when cold. When the engine is warm and I turn the
> engine off and then try to restart it, it acts like the battery is nearly
> dead. I’ve had the batteries checked at two locations and both say the
> batteries are good. Once the engine is completely cold, the coach starts
> just fine.
>> I recently had both the alternator and starter replaced thinking they
> were part of the problem (they need replacing anyway) but that did not
> solve the problem.
>> After stopping with the engine not running I get a 12 volt reading from
> the battery, and while the engine is running I get a14.5 reading at the
> battery, so it appears that the batteries are charging while the engine is
> running
>> Coach runs fine until I stop, then it barely cranks over, until it is
> cold again several hours later.
>> thanking everyone in advance for your thoughts.
>>
>> David Gardner
>> 1976 Birchaven (455 motor)
>> Oxnard Ca
>>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] (UPDATE)Engine starts when cold, won't crank when warm [message #307380 is a reply to message #307361] Mon, 19 September 2016 02:08 Go to previous messageGo to previous message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
Ken Henderson wrote on Sun, 18 September 2016 19:43
David,

When you say you have 12.5 VDC at the starter, is that with the starter
activated? Otherwise, it's a virtually meaningless number. It's the
voltage under load that's important, and it must be measured at the battery
cable BOLT on the starter -- NOT at the cable end.

I've seen two instances within the past 6 months, one of them my own, where
similar problems were due to battery cables which were apparently good, but
the end terminals did not make perfect contact with the cable itself. In
one instance, there was smoke from the terminal while cranking. The other
terminal pulled off under severe manual twisting -- revealing severe
corrosion. New cables cured both problems.

Ken H.


On Sun, Sep 18, 2016 at 7:53 PM, David Gardner wrote:

> Thanks to all for your suggestions. They were all greatly appreciated. I
> have checked all my battery connections, and everything looks good.
> Both my batteries have been checked by two different battery stores, and
> they say the batteries are good.
>
> I have just noticed that when I put my key into the ignition, and depress
> it slightly, I get a buzz from the battery isolator. Is this normal?
>
> Over the last few days the coach has gone from starting when cold, to
> barely starting at all, to now not starting at all.
> I checked and I do have voltage (12.5) going down the starter.
> At the moment I am only getting a click when I turn the key to start the
> engine. Batteries are still showing 12.5 volts when I check the battery
> with the volt meter.
>
>
>> On Sep 16, 2016, at 5:00 PM, David Gardner wrote:
>>
>> Haven't posted in a while, but I have one that has me stumped, and could
> use some advice..
>> My engine starts when cold. When the engine is warm and I turn the
> engine off and then try to restart it, it acts like the battery is nearly
> dead. I've had the batteries checked at two locations and both say the
> batteries are good. Once the engine is completely cold, the coach starts
> just fine.
>> I recently had both the alternator and starter replaced thinking they
> were part of the problem (they need replacing anyway) but that did not
> solve the problem.
>> After stopping with the engine not running I get a 12 volt reading from
> the battery, and while the engine is running I get a14.5 reading at the
> battery, so it appears that the batteries are charging while the engine is
> running
>> Coach runs fine until I stop, then it barely cranks over, until it is
> cold again several hours later.
>> thanking everyone in advance for your thoughts.
>>
>> David Gardner
>> 1976 Birchaven (455 motor)
>> Oxnard Ca
>>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Well, Colonel Ken beat me to it. I was going to ask the same thing. What it the voltage at the starter when you are trying to start it. What is the voltage at the battery when you are trying to start it? What is the voltage at the small terminal on the starter solenoid when you hear the clicking.

If the voltages at the starter are good, and the voltage on the small terminal on the solenoid is very low or bouncing around, then Jim Hupy's previous suggestion here of a bad ignition switch is the most probably cause. It could also be a bad neutral safety switch, but odds are it is the ignition switch.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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