very high idle... bad distributor... engine killer

E

ek_lektro

New member
Jul 27, 2007
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Just an update.. and a question:
First, the distributor cleaning and lubricating seemed to go pretty well.
Replaced the rotor and cleaned up the plugs while we were at it.
Wouldn’t start at first, so timing had to be set from scratch via directions from Miguel MGM,
and with the help of an experienced mechanic friend, going off cylinder #1, manually turning the engine…
setting timing… voila! Took it for a 40 mile test drive today, seemed to perform just fine, didn’t hear any ping.

But when i stopped at a gas station and went to start it again
with a hot engine, it turned over ‘slowly’, as if it was a low battery, but i know the battery and connections are solid.
(replaced starter, battery cables and ignition switch 10 days ago)
So, i remember once hearing something about how bad timing can cause difficulty starting... with a hot engine?
The engine starts up just fine when its cold. but after a hot drive, it turns slowly.
So do i need to advance or retard the timing slightly?
Thanks for the ongoing education, GMC mechanic friends!
cheers
Greg / SolarSonic / Los Angeles

> i was experiencing a very high idle when coming to a stop at traffic lights.
>
> consulted with Miguel at MGM GMC who told me to take a look at the distributor, and see if the weights
> are snapping back, or if they?re frozen up with rust, etc.
> Well, the little ?weights? on top seem to move just fine, but lo and behold, the part just underneath it
> (centrifuge advance?) feels really gummy, and needs to be manually moved back by hand.
 
> Just an update.. and a question:
> First, the distributor cleaning and lubricating seemed to go pretty well.
> Replaced the rotor and cleaned up the plugs while we were at it.
> Wouldn't start at first, so timing had to be set from scratch via directions from Miguel MGM, and with the help of an experienced mechanic
> friend, going off cylinder #1, manually turning the engine...
> setting timing... voila! Took it for a 40 mile test drive today, seemed to perform just fine, didn't hear any ping.
>
> But when i stopped at a gas station and went to start it again with a hot engine, it turned over 'slowly', as if it was a low battery, but i know
> the battery and connections are solid. (replaced starter, battery cables and ignition switch 10 days ago)
> So, i remember once hearing something about how bad timing can cause difficulty starting... with a hot engine?
> The engine starts up just fine when its cold. but after a hot drive, it turns slowly.
> So do i need to advance or retard the timing slightly?
> Thanks for the ongoing education, GMC mechanic friends!
> cheers
> Greg / SolarSonic / Los Angeles

Greg,

I think you still have a base electrical problem.

If advanced timing were the issue, the cranking speed will have very notable stalls at each compression and maybe even a backfire through the
carburetor. But, after driving in heating up the connections, you may have one or more high resistance connections in the starter power circuit.

Remember to check both the power cable and the ground connections to the engine.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Just retard it a hair by turning Dist counterclockwire

On Sat, Jul 27, 2019 at 6:42 AM Matt Colie via Gmclist <

> > Just an update.. and a question:
> > First, the distributor cleaning and lubricating seemed to go pretty well.
> > Replaced the rotor and cleaned up the plugs while we were at it.
> > Wouldn't start at first, so timing had to be set from scratch via
> directions from Miguel MGM, and with the help of an experienced mechanic
> > friend, going off cylinder #1, manually turning the engine...
> > setting timing... voila! Took it for a 40 mile test drive today, seemed
> to perform just fine, didn't hear any ping.
> >
> > But when i stopped at a gas station and went to start it again with a
> hot engine, it turned over 'slowly', as if it was a low battery, but i know
> > the battery and connections are solid. (replaced starter, battery cables
> and ignition switch 10 days ago)
> > So, i remember once hearing something about how bad timing can cause
> difficulty starting... with a hot engine?
> > The engine starts up just fine when its cold. but after a hot drive, it
> turns slowly.
> > So do i need to advance or retard the timing slightly?
> > Thanks for the ongoing education, GMC mechanic friends!
> > cheers
> > Greg / SolarSonic / Los Angeles
>
> Greg,
>
> I think you still have a base electrical problem.
>
> If advanced timing were the issue, the cranking speed will have very
> notable stalls at each compression and maybe even a backfire through the
> carburetor. But, after driving in heating up the connections, you may
> have one or more high resistance connections in the starter power circuit.
>
> Remember to check both the power cable and the ground connections to the
> engine.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Sounds like a heat soak problem in the starter motor. Try some temporary
heat shield around it between the exhaust system and starter. Not near any
wires please, if you make them out of metal. Might also try high
temperature sleeving around positive battery cable that feeds the starter,
and absolutely, for sure, check all grounding points, including the strap
between the transmission and frame.
Jim Hupy
Salem, Or. (Presently at a combined rally at the Great Oregon Steam Up.
Funny, steam engines don't have any electrical or starter problems to fuss
over)

On Sat, Jul 27, 2019, 6:42 AM Matt Colie via Gmclist <

> > Just an update.. and a question:
> > First, the distributor cleaning and lubricating seemed to go pretty well.
> > Replaced the rotor and cleaned up the plugs while we were at it.
> > Wouldn't start at first, so timing had to be set from scratch via
> directions from Miguel MGM, and with the help of an experienced mechanic
> > friend, going off cylinder #1, manually turning the engine...
> > setting timing... voila! Took it for a 40 mile test drive today, seemed
> to perform just fine, didn't hear any ping.
> >
> > But when i stopped at a gas station and went to start it again with a
> hot engine, it turned over 'slowly', as if it was a low battery, but i know
> > the battery and connections are solid. (replaced starter, battery cables
> and ignition switch 10 days ago)
> > So, i remember once hearing something about how bad timing can cause
> difficulty starting... with a hot engine?
> > The engine starts up just fine when its cold. but after a hot drive, it
> turns slowly.
> > So do i need to advance or retard the timing slightly?
> > Thanks for the ongoing education, GMC mechanic friends!
> > cheers
> > Greg / SolarSonic / Los Angeles
>
> Greg,
>
> I think you still have a base electrical problem.
>
> If advanced timing were the issue, the cranking speed will have very
> notable stalls at each compression and maybe even a backfire through the
> carburetor. But, after driving in heating up the connections, you may
> have one or more high resistance connections in the starter power circuit.
>
> Remember to check both the power cable and the ground connections to the
> engine.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Not sure if it applies here... I had a SBC (45 years ago!) that had similar
hot start issues. I went thru the usual starter/cable/timing exercises.
Time it to start cold and no hot start. The problem went away after I
replaced the timing chain. Stretched quite nicely it was.
Russ

On Sat, Jul 27, 2019, 2:00 AM Ek Lektro via Gmclist
wrote:

> Just an update.. and a question:
> First, the distributor cleaning and lubricating seemed to go pretty well.
> Replaced the rotor and cleaned up the plugs while we were at it.
> Wouldn’t start at first, so timing had to be set from scratch via
> directions from Miguel MGM,
> and with the help of an experienced mechanic friend, going off cylinder
> #1, manually turning the engine…
> setting timing… voila! Took it for a 40 mile test drive today, seemed to
> perform just fine, didn’t hear any ping.
>
> But when i stopped at a gas station and went to start it again
> with a hot engine, it turned over ‘slowly’, as if it was a low battery,
> but i know the battery and connections are solid.
> (replaced starter, battery cables and ignition switch 10 days ago)
> So, i remember once hearing something about how bad timing can cause
> difficulty starting... with a hot engine?
> The engine starts up just fine when its cold. but after a hot drive, it
> turns slowly.
> So do i need to advance or retard the timing slightly?
> Thanks for the ongoing education, GMC mechanic friends!
> cheers
> Greg / SolarSonic / Los Angeles
>
> > i was experiencing a very high idle when coming to a stop at traffic
> lights.
> >
> > consulted with Miguel at MGM GMC who told me to take a look at the
> distributor, and see if the weights
> > are snapping back, or if they?re frozen up with rust, etc.
> > Well, the little ?weights? on top seem to move just fine, but lo and
> behold, the part just underneath it
> > (centrifuge advance?) feels really gummy, and needs to be manually moved
> back by hand.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
I feel that the reason the issue disappeared after the timing chain change
was that some if the main battery cables were disconnected and reconnected.

On Sat, Jul 27, 2019 at 7:27 AM Russell Mehlenbacher via Gmclist <

> Not sure if it applies here... I had a SBC (45 years ago!) that had similar
> hot start issues. I went thru the usual starter/cable/timing exercises.
> Time it to start cold and no hot start. The problem went away after I
> replaced the timing chain. Stretched quite nicely it was.
> Russ
>
> On Sat, Jul 27, 2019, 2:00 AM Ek Lektro via Gmclist <
> gmclist>

>
> > Just an update.. and a question:
> > First, the distributor cleaning and lubricating seemed to go pretty well.
> > Replaced the rotor and cleaned up the plugs while we were at it.
> > Wouldn’t start at first, so timing had to be set from scratch via
> > directions from Miguel MGM,
> > and with the help of an experienced mechanic friend, going off cylinder
> > #1, manually turning the engine…
> > setting timing… voila! Took it for a 40 mile test drive today, seemed to
> > perform just fine, didn’t hear any ping.
> >
> > But when i stopped at a gas station and went to start it again
> > with a hot engine, it turned over ‘slowly’, as if it was a low battery,
> > but i know the battery and connections are solid.
> > (replaced starter, battery cables and ignition switch 10 days ago)
> > So, i remember once hearing something about how bad timing can cause
> > difficulty starting... with a hot engine?
> > The engine starts up just fine when its cold. but after a hot drive, it
> > turns slowly.
> > So do i need to advance or retard the timing slightly?
> > Thanks for the ongoing education, GMC mechanic friends!
> > cheers
> > Greg / SolarSonic / Los Angeles
> >
> > > i was experiencing a very high idle when coming to a stop at traffic
> > lights.
> > >
> > > consulted with Miguel at MGM GMC who told me to take a look at the
> > distributor, and see if the weights
> > > are snapping back, or if they?re frozen up with rust, etc.
> > > Well, the little ?weights? on top seem to move just fine, but lo and
> > behold, the part just underneath it
> > > (centrifuge advance?) feels really gummy, and needs to be manually
> moved
> > back by hand.
> >
> > _______________________________________________
> > 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
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
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