intermittent starter failure

[Frozenoak]

Good morning,

My 1974 Cheyenne Super C10 with 350/THM350 has developed an intermittent starting condition.  She starts fine most of the time but once in a while when I turn the key, noting happens.  Nothing.  The power in general is still present as the lights, indicators, clock still work but the starter doesn't react.  I am assuming right now that it's a grounding issue but I don't know where to start. 

Should I pull the steering column apart?  Start at the fuse box?  Start at the Starter?  Should I just rewire the whole darn thing?

As far as I can tell the the truck is essentially stock with the exception of the air filter being replaced with aftermarket, and parts of the AC are missing.  It may also be of help knowing that most of the instruments in the dash don't function and the ones that do can't be trusted (Fuel Level indicates half a tank when it's empty, Speedo's about 20% slow, Clock works but I can't figure out how to change the time, Odometer's frozen)  There are bolt on aftermarket tach and voltmeter that function, independently of the dash.  The radio has been disconnected from the wire harness but is still present.

I hope this is enough information to get feedback but feel free to ask any clarifying (or other) questions.  I'd like to get this figured out as quickly as possible as this is the second vehicle in a two person household.  We carpool when we can but it's not always possible.

Regards,
Dale

Edit: I should add that the issue seems to self resolve, meaning when I come back to the truck an hour or two later she just starts right up.

[Henry]

Hi Dale:
When you say it doesnt start, you mean that the started doesnt turn over...right? Do you  hear a clicking noise when you turn the key to start? Does it crank and start OK when it is cold? Does it refuse to crank when it is hot?  If everything else electrical seems to be working normal except for the no crank, I would first suspect the starter solenoid....it sounds as if it has a problem that it doesnt want to work when it is hot. I would take the starter and solenoid off as a pair and inspect the solenoid contacts and then take both of them to a car parts store to have them bench tested.
Regards,
Henry

[Frozenoak]

When you say it doesnt start, you mean that the started doesnt turn over...right?
              Yes, the starter doesn't do anything.

Do you  hear a clicking noise when you turn the key to start?
              No, I hear nothing.

Does it crank and start OK when it is cold?
              Yes, when it does crank

Does it refuse to crank when it is hot?
               No, I usually have this problem when it's cold, or maybe mildly warm.  This morning it was at the gas pump after filling up.  The time before it was at the pub after sitting for about 2 hours.

I purchased a new Starter with Solenoid after the first time it happened but then the truck started right up...  Maybe I should start with replacing that.

Thanks for the help.

[bd]

Before marching through a list of replacement parts, at the next occurrence of symptoms, jiggle/shift the gear selector out and into park or neutral a few times and then try to crank the engine.  If the engine still doesn't crank, use an incandescent test light and probe for power on the "S" terminal of the starter solenoid while an assistant attempts to crank the engine.   In other words, determine whether the starter solenoid is receiving a crank signal.

[Frozenoak]

Thanks for the advice.  I did try to jiggle the gear selector, including trying to start in neutral.  I also tried turning the wheel, turning the key back to ACC then start, and pounding on the steering column.  Of some note, and just remembered, when I first got the truck, the Hazard Light switch was stuck on and I had to use some considerable force to disengage the switch.  Could that have anything to do with my current situation?  I'll put together a test light / fixture when I get home.  Do you have a picture of what you use?

[bd]

I use a Snap-On mini incandescent test light (image).  Use an incandescent test light for general wiring diagnoses.  The incandescent test light places a small current load on the circuit, which is more likely to reveal the presence of unwanted circuit resistance that results in low load voltage.

[Frozenoak]

Thank you.  I'll pick one up on my way home.  Just as a sanity check, would my multi-meter be an effective tool for electrical troubleshooting?  That's kind of why I bought it.

[Frozenoak]

Well, the good news is the problem isn't intermittent any more.  The bad news is I don't have an extra pair of hand to help tonight.  The ugly is it's stuck in a gas station parking lot surrounded by tweakers. 

Because I already have one, I'm going to pull the starter and replace the solenoid (turns out I only bought the solenoid) and reinstall it tonight.  If that doesn't do it, I'll be calling a tow truck.  A closer inspection of the wires indicates a severe need of replacement.  Does this website sell Ron Francis harnesses?

[bd]

Just as a sanity check, would my multi-meter be an effective tool for electrical troubleshooting?  That's kind of why I bought it.

Both a high impedance analog multimeter (VOM/VTVM) and a digital multimeter (DMM/DVM/DVOM) are valuable tools for electrical diagnoses.  Both types of meter (high impedance analog vs digital) are ideal for measuring voltages in operating circuits because both have a sufficiently high internal resistance that neither type of meter will increase the current flowing through the circuit being measured, hence, the voltage indications are highly accurate.  However, using a voltmeter requires an effective working familiarity with Ohm's Law, which expresses the physical relationship between voltage, current and resistance.  Essentially, chasing an electrical problem with a voltmeter requires adequate skill to accurately interpret the measurements.  It's not that a voltmeter will lie to you, but you can measure voltages that are virtually meaningless, which can leave you thoroughly befuddled and the proud owner of diagnostic fiction if you aren't thoroughly conversant with Ohm's Law.  I've observed many professional technicians dig a ditch of grief by misusing their multimeters.

In contrast, an incandescent test light is a beautifully simple device that provides a simple visual indication of available power.  If a test light illuminates, there's power.  If a test light doesn't illuminate there's no power.  A "dim" test light simply indicates there is diminished power.  If a test light indicates low power (dim illumination) a voltmeter can be used to identify precisely what is occurring.

So the answer to your query is, you should have both.

Well, the good news is the problem isn't intermittent any more.  The bad news is I don't have an extra pair of hand to help tonight.  The ugly is it's stuck in a gas station parking lot surrounded by tweakers. 

Because I already have one, I'm going to pull the starter and replace the solenoid (turns out I only bought the solenoid) and reinstall it tonight.  If that doesn't do it, I'll be calling a tow truck.  A closer inspection of the wires indicates a severe need of replacement.  Does this website sell Ron Francis harnesses?

Try starting it one more time.  If it still doesn't crank, before pulling the starter, make sure the transmission is in park and the e-brake is set, then try using a jumper or short screwdriver to jump the starter solenoid battery cable stud (B+) directly to the solenoid "S" terminal to see if the starter will crank.  If it cranks, try it one more time with the key on.  You might be fortunate enough to get it running and drive it home to diagnose/repair it.

[Frozenoak]

Thanks bd and Henry, I ended up getting it towed.  There's more going on that I can take care of in a parking lot.  I'll be digging into it this weekend when I have some time and focus.  Some of the wires under the hood have cracked and peeling insulation and some look like they have overheated.

[Frozenoak]

Well, I went the not so smart route.  I replaced the starter solenoid with no results.  Then I replaced the wiring harness with a Ron Francis harness (needed to happen either way) also with no results.  Then I sat on it for a while. 

Replaced the whole starter yesterday and she started right up.


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[bd]

Glad you found the problem and got it running.  And, just think of all the experience you have now.   

[A robs 23]

I am having a similar issue. I am preparing for an engine swap right now, so I will likely replace the whole starter at the same time. Glad to hear yours is fixed.


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