Full Size Jeep Network

Greetings to all.
I have a 78 4dr Wagoner with 360
It started with when it would be able to start fine but after it runningfor about 30 minutes in this time you can turn it off and restart it no issues then out of blue, try to start and nothing no noise no clicks
Wait a day or two and it starts fine. Cycle all over again.
What I have done and replaced
New cables both of them
New starter solenoid
Remanufactured starter
New ignition module
New coil
New cap and rotor
Plug Wires
Plugs
Carb rebuilt
Rebuilt alternator
P/S pump remanufactured
Steering box remanufactured
I took a reading and I have at terminal I starts at 6.9v and increases to ll.7v and terminal S is 9.5 v as long as key is turned.
Would not having 12v to the terminal would cause it not to ingauge the solenoid to send power to starter?

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I had similar issues last year. Started with new battery cables. When I replaced the engine to frame ground strap (left side motor mount), everything electrical got much better and the fuel gauge started working (as good as one might expect for a Jeep).

I'm not in favor of throwing parts at a problem, but I would look at the ignition switch, or less likely, the neutral safety switch. Hot wire it, jumper the solenoid and see if it starts. Make sure it's in park, brake set!

Low voltage often means current limited (high resistance somewhere). You need current and voltage to switch the solenoid.

Use your multimeter and trace down the problem.

Jokerrw wrote: I took a reading and I have at terminal I starts at 6.9v and increases to ll.7v and terminal S is 9.5 v as long as key is turned.
Would not having 12v to the terminal would cause it not to ingauge the solenoid to send power to starter?

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Welcome to the forum!


I assume your "I" and "S" readings were both when the key is turned. (I also assume this is the 'start' position)
Does 'I' show any voltage reading when the key is in the off position?
When you have the key turned to the start position and "I" is showing voltage, what does the large post to the starter voltage read? It should closely match the reading at "I".
What's the voltage at the battery side of the solenoid when the ignition is in the off position and no other accessories are on?

9.5V should be enough to get the solenoid to engage. The reading at the "I" post would indicate that it is either engaging OR is stuck partially open. (This is why I want you to test "I" with the key off)

I will check later today and get back to you guys. All the parts that where replaced because of visual damage or they where tested and deamed defective. They where not just replaced to chase a problem.

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With key off no voltage reading at terminal I
Large post is same voltage plus or minus a volt.
I sanded under the mounting bracket for a good ground. So far she is starting on demand. I am thinking if it won't start again it must be the signal from the ignition switch.

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That's good news!

It could be the 'neutral' safety switch as well. Next time it won't start try putting in it neutral and see if it will crank.

Will do thanks again I owe you guys a drink if we ever meet up.

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