So then the new starter originally worked, and then all of a sudden started spinning slow? Did this happen with all three of the starters you mentioned, or just the first new one to get installed?

Keep in mind that if it was a remanufactured starter, any kind of failure is possible. Some remanufactured parts are every bit as good as new, and some aren't worth the trouble to toss them in the trash.

Did Autozone just spin test it, or did they look at the amp draw as well? A starter can spin apparently well during a bench test while drawing too many amps. It'll spin fine on the bench, but poorly in the vehicle. If they didn't pay attention to the amps...I would take it back and have them do it again. If Autozone's bench tester doesn't have the ammeter (not likely), take it to Advance Auto Parts---theirs definitely can give you the amp read-out.

If the battery is fully charged, and the starter is not defective, then I agree that you should check that positive battery cable. Could be the bad fusible link that was mentioned above, or even broken copper resulted from the removal of the original bad starter.

Have you tried turning the crankshaft by hand (with a ratchet or breaker bar) to verify that the engine is turning normally? (disconnect the battery when doing this)

 

Did the engine have any problems prior to this? I am wondering if something has broken internally that is not allowing the engine to rotate.
If all was fine and then the starter just went out, then I suggest pulling back the red and black plastic boots on the battery cables and checking for corrosion...not just where it screws into the battery, but where the cable attaches.

If the engine has an internal failure then that is a different path to take.

 

The engine is in great shape I have no concerns with that.

Every starter that has been on this car has done the exact same thing.

I just tested to power at the starter while cranking. Before cranking it was at 12.27 volts and while cranking it dropped to 8.3...which is not good. I tested at the battery itself and it was the same...12.27 to 8.3. When I ran the same test on our blazer that starts fine it was 12.5 or so and when I put the meter on the battery during cranking it only dropped to 11.5.

What would cause the sudden drop in voltage while cranking? Resistance in the wire? Should I just go ahead and replace the cable to the starter? It's easy enough to do. Thanks for the help and ideas guys. My dad and I know cars but this one has both of us stumped.

Zach

 

Bad battery or bad connections. Have you tried swapping the battery between the two trucks?

 

Yes we've tried both batteries in this truck. We swapped the one from the other working blazer to this one and it does the same. So the wire is good or bad you think? The connectors to the battery are cleaned up and the terminals are new.

 

Have you tested the resistance of the main positive wire to the starter?

 

It almost sounds like a short. In terms of the sudden drop in volts, that is. I would think that if it was a weak connection, it would act like a loose battery connection; and the power on the vehicle would go out whenever you tried to engage the starter (all dash lights, instruments, headlights, everything). With Blazers, though, anything can be possible...

When the starter on my Blazer went, it had developed an internal short. The second I would turn the key to crank the engine, I would knock a fully charged, good battery down to half-capacity. The last couple of times that the starter worked, it turned very slowly and sounded sick. After that, it just drained my battery without trying to turn over at all.

Something has got to be wrong with your positive cable (the large one to the battery) or possibly a short in the circuit. Unless you're having particularly bad luck with a whole batch of faulty starters (doesn't happen often).

But as far as testing the starter goes, you want to see how many amps it's drawing---not volts.

Test the positive battery cable's resistance from the starter terminal to the battery terminal, and inspect the insulation for any cracks or chafed spots---especially where the cable is secured to the engine or frame.

Another question.....when you turn the key, what does the starter drive engagement sound like? Does it sound normal, or does it sound like it's having a hard time engaging the ring gear on the flywheel?

 

Yes I have checked the resistance to the starter. I went with a wire from the battery to the starter a few days ago and it still spun real slow.

The update is that I replaced the big wire that runs from the battery to the starter. The cable I used is about twice the size of the old one. It sounded like it was spinning faster...but still not fast enough to start. So it helped but it's not the cause of the car not starting.

Any more ideas? Could one of the ground wires that come from the negative side of the battery be bad and cause the power drop?

Everything else sounds good, the motor makes no noise and the starter engages just fine.

 

Have you tested the resistance from the battery negative to the engine block? How is it? Continue testing while you attempt to start the engine.

 

Try swapping out the cables, one at a time, from the good vehicle to the bad vehicle. I'm still betting that is your problem.