Slow crank no start

Freightshaker · Sep 3, 2013

Got in truck tonight and it slooow cranked. Tried a couple of times and it picked up and went. So I figured something was left on.tossed my son in truck and went to work on someone's home AC unit. The repair took about ten minutes so I left it running. Truck ran fine no issues. On the way home I stopped at some family's house to drop off some hedge trimmers and I forgot and shut it off to chit chat. When I went to start it it just slow cranked. Hooked another psd to it with no change even after letting them sit for ten to fifteen minutes. Disconnected jumpers and took out meter. Both batteries were at I think about 12.6v. Checked at starter and it was was the same but dropped on start pole to 8v when we tried starting. I was at wits end with my son crying since he was tired. So I hitched a ride home. Laying in bed right now my issue is not jumping right out at me. Looking for suggestions

co04cobra · Sep 3, 2013

Probably the starter itself. Reload test the batteries, and check your alternator.

ghohouston · Sep 3, 2013

Either your batts/alternator have crapped out, or your starter has. Also make sure all your connections are corrosion free

Freightshaker · Sep 4, 2013

My thoughts right now are starter. I just haven't seen one fail like that where it works but at half speed. My plans for tonight is to double check post cleanliness/tightness, load test batteries, and if I'm still unsatisfied pull starter. I did try feeling all connections for a hot one and see if any were giving me smoke signals but no luck just a hot starter.

ghohouston · Sep 4, 2013

Its probably the starter. Mine was foing the same thing for a few months and it finally gave up one say. I bought a new starter, and it spun over like new

Freightshaker · Sep 4, 2013

Cool glad to hear that. Thanks for your thoughts so far fellas.

co04cobra · Sep 4, 2013

I have seen several fail that way over the years. Not extremely common, but does happen.

Lethalthreat7.3 · Sep 4, 2013

Sounds like starter pulling excessive amps. Did you try smacking it? Also make sure your batteries are recovering and no corrosion on the terminals.
Using your dvom, hook up to -&+ and make sure the voltage slowly increases as they sit.

Freightshaker · Sep 4, 2013

As much battery/amps I put to it, I figured I was pretty much eliminating batteries and terminals. I am definitely servicing and testing them to rule them out though. The cranking rpms wouldnt really taper off like dying batteries and would never increase no matter how many batteries I stacked behind. I'll get to cleaning testing and tightening tonight thats for sure and probably starter pulling.

Freightshaker · Sep 4, 2013

Cleaned terminals up and load tested batteries. Everything looked good. Pulled starter and disassembled. Two brushes were completely bottomed out and commutator looked like poo. Having wife take to a auto electric shop tommorrow morning. If it isn't the starter it was probably have taken a dump next week lol

hwrdbd · Sep 8, 2013

I've been dealing with the same issue myself, just reluctant to drop the coin on a starter lol. Figure its the only thing it can be though, 98% of the time it slow cranks, randomly it will spin over fast. I suppose its time for one of those fancy hi torque starters