I have a 88 5.7 TPI that I just finished restoring and really haven't drove too much because of a starting problem. The car starts fine and the starter seems to engage okay most of the time but I did have a incident the other day where the starter would engage and spin but the motor would not turn over. I turned the crank pulley over with a breaker bar a little and when I tried it again it started fine. Any idea what might cause this and how to fix? Thanks.

 

Sounds to me that you have a couple of teeth missing on the flexplate. When you turn the motor off, it is a crap shoot if the missing teeth stop at the starter gear. If it does, the starter could spin until you manually rotate the motor a few degrees to move the missing teeth away from the starter gear. I found this out the hard way when I did my TPI swap on my Monte Carlo SS. Before I did the swap. I could hear a click when I cranked the motor. One click per revolution. When I pulled the motor to do the swap, I saw that the flexplate had a tooth missing. I pulled out my shop manual and read that the starter needs to be shimmed. The shop manual has good details on how to do this.

Fred

 

If it's an older starter, then the clutch inside the starter might be slipping and it's just time to replace the starter. If you can rotate the pinion gear both directions by hand without resistance then that's a surefire indicator the clutch is toast.

Starter has a clutch between pinion gear and motor. The clutch grabs when the starter is driving the engine during crank, and slips when the engine goes faster than the starter. This happens every engine start up. The clutch eventually wears out and begins slipping, first intermittently and eventually progressing to all the time. Using an excessively high CCA battery will also cause the clutch to slip.