(UPDATE)Engine starts when cold, won't crank when warm

[mr.green]

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.

>
> 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
>

 

[sgltrac]

Ignition switch.

Sully
77 eleganza 2
Seattle

> 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 >
> > 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
>

 

[Ken H.]

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.

> 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.
>
>

> >
> > 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
>

 

[Ken B]

> 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.
>
>

>
> > 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.
> >
> >

> >>
> >> 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
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

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