I have an 07 1500 with the 5.7L. The other day out of the blue it wouldn't start for my wife. I put a new starter on the other day and it has started having the problem again. Sometimes it will turn over just fine and other times it will not. It's like it begins to spin over and then stops. Topside and bottom connections seem fine. I tested battery voltage and CCA and it checked out. I haven't ran all the grounds down yet but its just weird. Any input or info on this or where I need to check for grounding issues will be much appreciated.

 

I recommend you check the grounds first. There are videos for checking starter grounds that provide excellent explanation.
The basic test is to see how much battery voltage drops when starter is engaged.
You should start with a battery voltage of 12.7 -12.8, 12.6 at minimum.
Read battery voltage with voltmeter while second person engages starter. Check voltage when starter is not turning but key in start position. The higher the voltage the less demand from the starter, the lower the voltage the higher the demand from the starter.
If you are seeing a high voltage, around 12.0v with starter engaged then most likely a wiring or ground problem.
If you see a low voltage, 9.5 or so, then there is resistance to turning that is more likely mechanical.
These voltages are estimates. You need a known good battery to test your starting issue.

 

Ok i checked voltage with key off and had 12.6 or so and then when the starter was actually engaged and turning engine over and it never dropped below 10. I found this test on YouTube. I don't know much about batteries and voltage but will check what you suggested this evening after work. Thanks

 

The voltage drop test sounds like the starter power demand is correct.
What are you hearing? does it sound like the starter is working and trying to turn the engine? Is the starter spinning but the engine is not turning? Any gears grinding?

 

Starter seems to be getting power and sounds like it actually does start to turn engine over and then just stops. No grinding or broken teeth noise. Someone on another place suggested maybe failing TIPM but it only has this one weird symptom. Sometimes it does turn over for a couple of seconds before it fires up. Its honestly like the starter is turning but like the flywheel or flex plate better have missing teeth and it can't turn but it does turn it just not much at all before it stops.

 

Do you recall if the wear on the old starter gear looked normal?
So the new starter makes same noise as old starter?
I think I would take out the new starter and examine the gear. Bench test the new starter. Then take a look at the flywheel teeth.
Your battery sounds like it is good.

 

Looked just fine. New looked same as old. Didn't check flywheel teeth. How can I look at all of them? Like how can I spin the motor over to examine? And yeah same noise. You can literally hear the starter engage and start turning the engine over and then it just dies.

 

Think I would be tempted to do a starter draw test..... (needs an ammeter...) See what starter draw is while cranking, if it draw drops off when the engine stops cranking.... (might be able to see something with just a volt meter too....) If the draw remains, but, the engine doesn't turn, try taking off the serpentine belt, and trying again.

 

how do I perform starter draw test? Only thing I currently have is volt meter

 

Put your meter on the battery, have someone else start the truck, see what voltage does when the starter stops turning the motor... If it stays low, the starter is still trying to turn the motor. If it bounces back up, it isn't. Might just be a weak relay in that case.