Engine won't start or turn over

Russell

Russell

Active member
Jan 2, 2017
357
88
28
Dunedin, Florida
Our '78 403 will not start. I drove it home Friday. It started normally. I stopped for gas, and it started normally after that. On Saturday, all I did
was generator maintenance, no work at all on the coach engine. On Sunday we got in it to take it back to storage and it won't start. The battery is
fine. There is no "click" sound at the starter. I tapped the starter with a rubber mallet, still nothing. I read through this thread about a 455
that would not start.

http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&th=41398&goto=336892&rid=5215

I tilted the steering wheel all the way forward per Jim Hupy's suggestion, still no start.

The headlights do not dim when I try to start it.

I jumpered the double purple plug to bypass the neutral safety switch per the Starting Circuit Diagnosis chart on page 6Y-62 of the maintenance
manual. Still nothing.

I am ordering a new starter, but I'm not convinced that is the problem. How to I check the rod that extends down the steering column from key
mechanism? Any other suggestions?

--
Russell Keith,
1978 E2 "Harry" 403 (still carbureted), Danny Dunn Tranny, Thorley, Stock Brakes w/Remote Vacuum Brake Booster, Quad Bags, Dakota Digital Dash, 6.5 kW
Onan, Dunedin, Florida
 
Use a steel hammer on the starter.
Rubber mallet does not produce the shock type impact.
Check you neutral switch.

On Sun, Jun 16, 2019 at 3:03 PM Russell Keith via Gmclist <

> Our '78 403 will not start. I drove it home Friday. It started normally. I
> stopped for gas, and it started normally after that. On Saturday, all I did
> was generator maintenance, no work at all on the coach engine. On Sunday
> we got in it to take it back to storage and it won't start. The battery is
> fine. There is no "click" sound at the starter. I tapped the starter with
> a rubber mallet, still nothing. I read through this thread about a 455
> that would not start.
>
>
> http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&th=41398&goto=336892&rid=5215
>
> I tilted the steering wheel all the way forward per Jim Hupy's suggestion,
> still no start.
>
> The headlights do not dim when I try to start it.
>
> I jumpered the double purple plug to bypass the neutral safety switch per
> the Starting Circuit Diagnosis chart on page 6Y-62 of the maintenance
> manual. Still nothing.
>
> I am ordering a new starter, but I'm not convinced that is the problem.
> How to I check the rod that extends down the steering column from key
> mechanism? Any other suggestions?
>
>
> --
> Russell Keith,
> 1978 E2 "Harry" 403 (still carbureted), Danny Dunn Tranny, Thorley, Stock
> Brakes w/Remote Vacuum Brake Booster, Quad Bags, Dakota Digital Dash, 6.5 kW
> Onan, Dunedin, Florida
>
> _______________________________________________
> 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
 
He's already bypassed the safety switch on the column. Take your ten foot #16 clip cord - you DO have one don't you? - and clip it on the terminal
where the small wire is connected, touch the other end to the battery hot terminal and see if it spins. Report back :) If it spins, find where it
isn't making it from the battery to the solenoid. Usually it's the switch located at the bottom of the steering column. Chuck Boyd understands
steering columns, ask him how to test.

--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
 
I wasn't clear. The 'small terminal' is the small terminal on the starter solenoid.\

--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
 
> Our '78 403 will not start. I drove it home Friday. It started normally. I stopped for gas, and it started normally after that. On Saturday, all I
> did was generator maintenance, no work at all on the coach engine. On Sunday we got in it to take it back to storage and it won't start. The
> battery is fine. There is no "click" sound at the starter. I tapped the starter with a rubber mallet, still nothing. I read through this thread
> about a 455 that would not start.
>
> http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&th=41398&goto=336892&rid=5215
>
> I tilted the steering wheel all the way forward per Jim Hupy's suggestion, still no start.
>
> The headlights do not dim when I try to start it.
>
> I jumpered the double purple plug to bypass the neutral safety switch per the Starting Circuit Diagnosis chart on page 6Y-62 of the maintenance
> manual. Still nothing.
>
> I am ordering a new starter, but I'm not convinced that is the problem. How to I check the rod that extends down the steering column from key
> mechanism? Any other suggestions?

Russel,

It is not likely to be the starter or solenoid. If the solenoid is getting the signal it will click. If you don't hear the click, a hammer is not
likely to be a help. A conformance check at this point can be to short the terminals on the back of the solenoid. If you have HEI, this will not
start the engine, but it may crank it and do an electric burn to what ever you used for the test. If that cranks, the starter is good.

The NSS is between (electrically) the ignition switch and the solenoid. Check from the hot side of that to the column with a test light.
Unfortunately, both sides of that switch are the same color, so I cannot tell you which is the important one to test. But, if neither of those two
make the light come on when you turn the key then dollars to donuts the switch on the column is at least out of adjustment. This only happens when a
coach is used (all the time).

That would be my first bet. What I can't remember right off hand is which way you probably want to more the switch. If you don't mind crawling on
the floor, the adjustment is easy. It is also easy to replace the switch if it has gone bad. That switch was used in GM product from about the turn
of the last century until the turn to the current century so they are very available.

Having a spare starter isn't stupid either. They have been out of production for 40 years and ours was only used with the 425 transmission.

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
 
> I wasn't clear. The 'small terminal' is the small terminal on the starter solenoid.\
>
>
> --johnny

There are two small terminals on the starter solenoid. On a points distributor coach one terminal goes to the distributor and the other goes to the
NSS and ignition switch for starting. On an HEI distributor coach, which your 1978 is, choose the terminal that has an existing wire going to it.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
To determine if you have an issue with your starter, connect a temporary
jumper wire from any known good positive 12 volt source to the starter
primary terminal on the solenoid where your wire from your ignition start
switch is connected. The minute you touch the jumper to a 12 volt positive
source, if the starter is good, it will crank.
Jim Hupy

On Sun, Jun 16, 2019, 8:56 PM Ken Burton via Gmclist <

> > I wasn't clear. The 'small terminal' is the small terminal on the
> starter solenoid.\
> >
> >
> > --johnny
>
> There are two small terminals on the starter solenoid. On a points
> distributor coach one terminal goes to the distributor and the other goes
> to the
> NSS and ignition switch for starting. On an HEI distributor coach, which
> your 1978 is, choose the terminal that has an existing wire going to it.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
I recently replaced the starter on my '76 and can confirm that there's just the big wire from the battery which is obvious, and a single small wire to
the solenoid which is not so obvious. The solenoid terminal is the one closest to the block and the wire is tucked in pretty tight around the
backside of the solenoid.

I would check those wires and the connections. A test light on the solenoid terminal will also tell you if you have the 12v signal from the ignition
switch making it down to the starter.

--
Todd Snyder, Buffalo NY
1976 Eleganza II
 
right where the steering column touches the floor on the back side is your neutral safety switch. You said you by-passed it, it should be a heavier
purple wire. If you hook a test light to that, you should see if your ignition switch is sending that 12v when you turn the key to "crank". then
you can start going further down the circuit towards the starter itself, or back to the ignition switch.

that purple wire should go across the dash, enter in behind the fuse panel in the glove box, and that is a connection to the engine harness
there(does not go through a fuse rather then just comes in behind the front panel where the fuses are and goes out to the harness. . it then
leaves the backside of the fuse block into the harness in the passenger hatch, down the wire-loom that goes to the forward passenger side of the
engine, where there is a T in the wireloom and exits and drops straight down by the fuel pump where it is routed along the oil cooler lines to the
starter.( small terminal closest to block on solenoid).

so there are a few spots you can check to test that when you go to crank, it gets 12v. jack up the coach a bit on the cross member and remove the
passenger side wheel liner gives you good access to those starter wires to put a test light to on the starter.

--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/
 
With a meter or even a test light and a friend to turn key, you can stop all the guessing and put away the hammer and actually troubleshoot.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
I would start at the starter with a test light and see that A) the connection from the battery is good; clean and tight and B) that the 12V signal is
getting to the solenoid. If they are both good, you know it's the starter. If one is missing, you can work back from there based on what is found.
That's just me though, I like to use a process of elimination. Skipping back most of the way up the chain towards the ignition switch doesn't really
tell you much imo.

But before that, I'd thump the starter body with a mini-sledge and see if it's just the brushes hanging. And if it is, have a good starter /
alternator shop rebuild it. I just had mine rebuilt locally by a one-man shop in the Buffalo NY area for $75. New USA solenoid and brushes, cleaned
up and painted. One day turn around. Cash or check only, no credit card. He said it was due, brushes were just about gone.
--
Todd Snyder, Buffalo NY
1976 Eleganza II
 
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