Intermittent Starter issues

[uconnjack]

Hi, I am having some intermittent starting issues that I am having a difficult time troubleshooting and was wondering if anyone here has any ideas.  Over the past week, my truck will occasionally not start (won't crank or turn over).  I can hear what sounds like the clunk/click of the starter solenoid, but the starter will not turn the engine.  If I retry several times, it will sometimes start, but not always.  I checked the voltage to both the high and low (ignition) amperage electrical connections, and both seem to be getting adequate voltage, but the starter won't always fully engage (just the clunk of the solenoid).  However, if I jump the solenoid with a screwdriver, it will start every time.

 

So if the starter won't always engage despite getting adequate voltage from both lines (implying there isn't an ignition/electrical issue), but does always start when jumping the solenoid (implying that the starter is functional), what could be the problem?  I am at a loss?

 

My only idea it that the starter is close to worn out such that even though the voltage is OK, that the amps provided by the ignition relay aren't strong enough to fully engage the faulty solenoid.  However, when I jump it from the main power line, the higher amps are enough to engage the solenoid.  Does this make sense, and is that possible? 

 

Thanks!

[sefiroxx]

If it always works with the screwdriver, then the wiring/fuse/relay are the problem - limiting amperage