I don't think my starter is getting full power from both batteries. It doesn't seem to crank very fast and I can only crank maybe 3 to 4 times before batteries are to weak to crank it.

Scenario:
Put in new Motorcraft battery driver side right before Christmas.
Passenger side was taken out and checked at store, checked fine.
Temps down to below zero currently, but also does this in 15-25 degrees.

Maybe starter going bad?

 

Check all of the connections (battery terminals, starter relay, starter) make sure they are good and clean and tight. If all are good, pull the starter and take it in and have it tested (several times). I have taken starters in and on the first test they past, on the second and third they got worse as the starter heated up.

 

I have rebuilt my own in past. Is it recomended for these?
Do they sell better one? It just doesn't seem right.

 

Only changed the one Batt?
The old one could drag down the good one.

Bill

 

check the heavy gauge wire to the starter, sometimes they corrode in the middle. If that isn't it take "both" batteries in for testing.

If that fails, inspect the starter for oil grit and residue on the surface, if there is some, take the starter off, and spray some electric parts cleaner in the housing, swish it around, and drain it a couple of times, then drain it out, if it is draining out as a brackish color you probably figured out your problem, let it sit to dry for 15-20 minutes, hook it back up and test. If that fixed it you had oil get into the starter, and oil in the starter can cause premature starter failure. You may want to pick one up and toss it in the back with a ratchet set just in case.

-Iasrap

 

i had same issue turn on the lights and then crank your truck and see if they dim drasticly if not its the starter mine went when i was an hour put a new one in and it was better then new

 

Changed starter (new $190). Not only did that fix my starting but the voltmeter goes straight up, before it would stay low. The guy who checked my starter said it was so bad that it was draining batteries instantly. The brushes were "fuzed" in the casing. and the lead wire to starter from solenoid was probably shorting cause it had red orange burn marks to it. I can't believe the difference.

 

Glad that you figured it out and got it fixed.