Replaced Starter Contacts. Still Intermittant Starting!!! Sleuth needed. (2 Viewers)

[roncruiser]

Roncruiser,
While you are checking/replacing the HD cables to the battery, also check the ground cable to the block and the smaller one to the body.

-B-

B, I'll do that. I've eyeballed the ground to the block, but have not done anything but tighten down the bolt. I have looked at and checked the smaller one to the body. Its good. I'll check and clean the main ground cable to the block this weekend. Replacing if necessary.

I personally wouldn't buy or swap anything until I knew what the problem was. Tests for starter operation are about as easy as it gets IMO.

ST

I'm in a quandary since the problem is intermittant. Can't really test it unless its happening, and it happens randomly. Not every turn of the key is a no-start.

 

[landtank]

I'll check and clean the main ground cable to the block this weekend. Replacing if necessary.

I doubt that you will see anything obvious even if the cable was bad. I'd just replace it.

 

[SUMOTOY]

I'm in a quandary since the problem is intermittant. Can't really test it unless its happening, and it happens randomly. Not every turn of the key is a no-start.

Low voltage at the starter is measurable, a bad ignition switch can be starter bypassed. A bad feed/ground will show up on a voltmeter Compare normal starting voltage drop at the battery with the no start voltage drop at the battery.

ST

 

[MARLIN375]

I hope everybody got their buck in the hat.............post 18,45

 

[roncruiser]

I hope everybody got their buck in the hat.............post 18,45

I hear ya. I'll know more before the weekend is over.

 

[maverick_sr71]

"Marverick's idea works well. Here's an article describing something similar:"


So it worked for you Ron? I hope so.

 

[roncruiser]

"Marverick's idea works well. Here's an article describing something similar:"


So it worked for you Ron? I hope so.

Hey Pete, haven't tried it yet. I'd like to know exactly what's wrong first before any rewiring at all.

 

[zcruiser]

Well, there are cheap parts that you can replace (cables from battery to starter, starter to ground), then move on to more expensive / time-intensive parts.

Have you tried a fresh battery? I was having intermittent starts on my 62, and the new owner finally decided to replace the battery and reportedly hasn't had any no-starts since.

 

[medtro]

If it is the switch I wouldn't go rewiring the truck to compensate for it, I'd just replace it. This is because it eventually won't work for that relay and then what?

Then you replace the relay.

 

[maverick_sr71]

Ron,
The problem is burnt and pitted contacts in the ignition switch. There's two ways to confirm this, 1) Replace the ignition switch, 2) Install the spot light replay.

 

[bhaines]

Next time it happens knock the starter with a hammer or something while turning the ignition on and i gurantee it will start first go. Please try it, if it starts first go then rplace the ignition switch.

 

[landtank]

Ron,
The problem is burnt and pitted contacts in the ignition switch.

How is it that the solenoid is energizing if the switch is bad?

 

[medtro]

How is it that the solenoid is energizing if the switch is bad?

Copy from post #54 by maverick_sr71.

If you look at the wiring diagram for the start system you'll see that all the power to pull in the start solinoid goes through the contacts in the ignition switch. These contacts become burnt and pitted over time and create a high resistance, thus the voltage being provided to the start relay is reduced and intermitantly the start solinoid will get power, but not enough to pull the soliniod in.

 

[SUMOTOY]

Copy from post #54 by maverick_sr71.

If you look at the wiring diagram for the start system you'll see that all the power to pull in the start solinoid goes through the contacts in the ignition switch. These contacts become burnt and pitted over time and create a high resistance, thus the voltage being provided to the start relay is reduced and intermitantly the start solinoid will get power, but not enough to pull the soliniod in.

... Exactly, then if you still ignore it the heat/arcing causes the ignition swith barrel to crack, and then intermittent becomes permanent. Ignition switches with no starting load last a lot longer IME. I *very* familiar with this issue, as Audis have some of the most notorious issues with ignition switches following this exact intermmittent no start path.

It's easy to bypass the ignition start switch. And, if the intermittent no start is due to ignition switch, you will see the failure.

ST

 

[landtank]

Copy from post #54 by maverick_sr71.

If you look at the wiring diagram for the start system you'll see that all the power to pull in the start solinoid goes through the contacts in the ignition switch. These contacts become burnt and pitted over time and create a high resistance, thus the voltage being provided to the start relay is reduced and intermitantly the start solinoid will get power, but not enough to pull the soliniod in.

EXACTLY... his solenoid IS energizing, IT'S CLICKING, so how could it no be getting the needed amperage through the switch?

 

[medtro]

These contacts become burnt and pitted over time and create a high resistance, thus the voltage being provided to the start relay is reduced.

This is like a voltage divider, with the higher resistance (from the contacts in the ignition switch) in the first part of the circuit, the voltage across the second part of the circuit is reduced.

With Ohm's Law V=IR, assuming the resistance in the solenoid doesn't change, current amperage is reduced with lower voltage. If the resistance in the solenoid is increased, the current will be even lower.

 

[landtank]

These contacts become burnt and pitted over time and create a high resistance, thus the voltage being provided to the start relay is reduced.

This is like a voltage divider, with the higher resistance (from the contacts in the ignition switch) in the first part of the circuit, the voltage across the second part of the circuit is reduced.

With Ohm's Law V=IR, assuming the resistance in the solenoid doesn't change, current amperage is reduced with lower voltage. If the resistance in the solenoid is increased, the current will be even lower.

I understand all that. You're missing the whole point, the solenoid is energizing, the problem as I see it isn't in the low side, it's in the high side.

Now if he turned the key and there was no click then I'd agree with the ignition switch theory as the solenoid was not energizing.

 

[medtro]

With lower current flows to the coil of the solenoid, a smaller magnetic force is produced to push the plunger to make contact with the contacts. When the plunger is not in proper contact with the contacts, this simulates the popular bad starter contacts click click click condition. Make sense?​

If the solenoid is energized with proper current juice, then I agree that the problem is in the high side (terminal 30).​

With that siad, a bad ground will get click click click too.​

 

[landtank]

I have to believe that having the plunger hit the contacts with enough force for you to hear it in the cabin of the vehicle would mean that the starter should turn.

 

[zcruiser]

Have to agree w. Landtank.... Clicking sound = plunger hitting the contacts.