Battery and charging test good but more and more the engine seems to have trouble turning over like the starter is getting "weak". Does that happen as opposed to it just failing completely? Once started everything is fine.

 

Ya they can do that, but check your connections at the starter and if all is good with the connections run quickly to the parts store for a new starter.

 

Yes of course. The windings will go bad, especially if the starter is stuck out and the engine is spinning it while you are driving.

Easy way to check is turn on your headlights, if the lights dim a whole lot and the starter is cranking slowly you most likely hav an issue with the starter. If the starter cranks slowly but the headlight only dim slightly or not at all could be a problem with ground, or shorting + cable.

That is a vague and primitive way of testing it but it will give you some idea so you can further evaluate it or feel more confident in your decision to purchase a new starter.

I dont know what tools you have available to you for diagnostics, so that way requires nothing.

 

One issue I have with this test is that it doesn't eliminate a weak battery.

On the flip side I was close to calling out a battery on a Ford F150 this summer because the engine would barely crank and when cranking the battery voltage dropped to the floor. Performed a starter draw test and found 1000 amps draw due to a faulty starter. A new battery wouldn't have helped that.

 

Even if you take it to Autozone or Advance they will test it and that isn't a foolproof test but it doesn't hurt.. ASE Doc was correct about the draw down test..

 

The bench test that they do at the parts store is an "unloaded" test. It will only prove that the motor activates and spins with no load placed on it. This is a completely different situation than being installed in the vehicle and trying to turn an engine.

 

I surprised that didn't melt the leads!

 

Yeah, and only a big bad battery like the yellow top Optima could have supported that kind of current. Fortunately, we looked at starter current right away before we tried cranking the engine too much.

 

I checked battery voltage at the starter and the switch wire and they were ok so I pulled the starter and bench tested it. It was fine so I put it back in and it all works fine. I cleaned all contacts so it was likely that but nothing looked bad enough to cause the problem. All's well that ends well. Thanks for the suggestions.