I just replaced the starter due to typical bad starter symptoms. As soon as replaced the vehicle started perfectly about 10-15 times. After driving for about 100 miles on the free way I stopped to get gas. Then when I turned the key..... nothing. After checking fuses and swapping relays still nothing. I disconnected the battery and left off for about 20-30 seconds. Upon reconnected the battery she started right up no problem. I am thinking a bad ECU but am looking for suggestions or recommendations. Thanks for looking!
It did nothing. Lights came up on dash but no noise at all, didn't turn over or anything. Car started no problem after disconnecting and reconnecting the battery
If all you did was disconnect the battery. I would first triple check all the battery cables and the terminals. Both ground and positive. You probably moved one is such a way you got a good connection for a small amount of time.
If cleaning and tightening all battery and starter cables doesn't do the trick, take the starter back and have it replaced. Unfortunately the Advanced Auto (or Autozone or Pep Boys, etc.) lifetime warranties on house brand starters, water pumps, alternators, etc. mean little more than the opportunity to change out defective parts multiple times at no additional charge before you finally get a good one, if you ever get a good one..
Store brand parts like that are always high on my list of initial suspects. But first, I would get a helper to turn the ignition switch to Start while you simultaneously measure the voltage at the starter. If the voltage is a strong 12 volts with the ignition switch in the Start position without the starter working, that's a bad starter.
There are two points from which to measure the 12 volts. Where the heavy cable connects to the starter solenoid, and at the smaller gauge control connection at the solenoid that comes from the starter relay. See if you get a switched 12 volts on the smaller gauge cable from the starter relay when the ignition switch is in the Start position and if you do, measure the 12 volts at the larger gauge cable. If both are present and at a strong full 12 volts, that's a bad starter. If the small gauge cable connector doesn't see 12 volts when the ignition switch is in the Start position, that would be caused by the starter relay or ignition switch. If both voltages drop off to a low voltage when the key is in the Start position, that indicates a bad or discharged battery or a dirty/loose/corroded battery connector.