84 GMC Diesel won't start

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  #1  
Old 10-25-06, 09:14 PM
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84 GMC Diesel won't start

I drove the truck yesterday ,making a few stops, with no problems at all.

Tonight I tried to start it and there was nothing.
No click nor stutter or any indication that power was going to the starter

The batteries are good

My thoughts are
1) Connection at the starter came loose

2) Neutral safety switch is bad

3) Bad ignition switch

Any other ideas

I just had to walk five miles to meet my wife and walk her home, I'm too old and fat to do it again
 
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  #2  
Old 10-26-06, 08:52 AM
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There's also a starter solenoid in the system. I would go to the solenoid with a test light (cheapies work well) and check out the power on both sides of the solenoid as well as the actuation wire attached to it. The key would have to be in the start position to have power at the latter.

You pretty well have the other possibilities listed.

Goog Luck.

Hope this helps,


Bob
 
  #3  
Old 10-26-06, 03:55 PM
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One possibility that may be round about what you just said.

First off let me say I know nothing about these diesels

There is some sort of a connection at the fire wall
Looks like a plastic block with two bolts coming out of it
One small and the other a littler bigger

There are two wires coming off of the larger bolt

One is a wire marked fusible link but there is no fusible link attached to it.
This wire attaches to two other wires that lead down to some sort of electrical component, that I can't remember the appearance of.
The wire coming off of the block at the firewall showed signs of excessive heat and had broken off at the connection of the three wires.
I hooked it back up with a wire nut for now and everything works, but that wire is getting hot

I don't drive the truck much so it should hold until I can get a Chiltons for the truck and correct the jerry rigging of the previous owner. And there's a bunch of correcting to do
 
  #4  
Old 10-26-06, 08:46 PM
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That sounds like the starter solenoid. The wire marked fusible link may have the fuse internal in the wire or it cold have been removed. If the wire marked for the link in it is getting hot, I would replace the solenoid. The amps drawn through it would only be the solenoid activation current.

It shouldn't be too expensive.

Hope this helps,

Bob
 
  #5  
Old 10-27-06, 08:44 AM
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After reading your first post I was thinking that that was it

Thanks

One more question
With GMs can you replace just the solenoid.
I know Ford solenoids are separate but I thought GMs were integral to the starter
 
  #6  
Old 10-27-06, 09:10 AM
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The starter solenoid on a conventional GM starter is mounted on the starter itself. Those can be replaced separate from the starter. I'm not sure if that's what they used on the diesel engines. If you have the piggy back solenoid on the starter, the part you have on the firewall is a relay for the starter.



Hope this helps,

Bob
 
  #7  
Old 10-27-06, 12:41 PM
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Ocoee:

There is something else I thought of that may shed some omore light on your problem. It sort of complicates it too.

That particular engine has glow plugs. The block on the firewall is likely a relay for the glow plugs and not for the starter. The fusible link protects the rest of the electrical system from the glow plug system. If the fusible link wire is getting hot, and probably got hot enough to melt the link, it's an indication you have a problem with the glow plugs/circuit.

That glow plug setup would also have a timer for the plugs to cycle. If the timer was bad and stayed on too long it could result in the hot wire. It would not be a good idea to use the glow plugs without the fuse in place to protect everything else.

That system isn't used on the big truck Cummins engines, but is on the Ford light truck diesel.

The ignition switch should still activate and click the solenoid. You may have to go to the starter solenoid (whatever type it is) and check the activation wires leading to it for current.

Hope this helps,

Bob
 
  #8  
Old 10-27-06, 10:09 PM
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Originally Posted by marbobj
Ocoee:
That particular engine has glow plugs. The block on the firewall If the fusible link wire is getting hot, and probably got hot enough to melt the link, it's an indication you have a problem with the glow plugs/circuit.
If the timer was bad and stayed on too long it could result in the hot wire.
Bob
BINGO,I think

The glow plugs switch at the ignition switch has been by-passsed by one of the previous owners jerry rigs
It now has a seperate push button to activate the glow plugs

There is usually an indicator light that goes off when the plugs are hot enough, this has also been by-passed so I just have to guess
I have no clue how long it should be so I count to fifteen and the truck usually starts.

My step father bought the truck about three months before he died and had not had time to un-bubba the truck.
But it is my inheritance and I would like to bring it back up. Cause it runs so good

It'll take some time now because I just quit my job to go back to school for a year
 
  #9  
Old 10-27-06, 10:13 PM
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One more thing

When the power went out
I lost the electric windows and door locks, AC fan and all components that are normally on when the key is turned on

The head lights, glow plug indicator light and gigarette lighter still worked
 
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