Q: 04 dodge Durango, 3.7 just changed engine,battery,and starter. Still won't crank over, getting power to solenoid,when key is turne

The most important thing to understand about electricity is it occurs on the atomic level. What appears to be a good connection to the human eye may not be to electricity. This is why we have test lights and multimeters for testing. It you have power to the solenoid, is the solenoid clicking? If it is, then that indicates the the primary circuit, the circuit from your key to the starter solenoid is working. You might want to see if a full twelve volts is available at the solenoid. I have seen many times where the solenoid is not recieving enough voltage and it won’t engage the starter.

If it is getting twelve volts, you want to make sure there is power at the battery cable where it connects to the starter, when you are attempting to crank the motor. Bad connections will become apparent when you are making them work. Such as during the action of turning the ignition key to the start position. A test light is good for this. It is fairly common for the bad connection for a starter to occur at the battery cable post to cable end. When attempting to crank the motor, there will be power at the battery post, but it will stop at the cable end. This would be a bad connection at the battery post. You can test both the positive and negative terminals this way. Perform this same test where the battery cable connects to the starter.

If these connection test good, the next thing to consider is a bad ground between the starter and the engine block. If the block is painted where the starter is mounted, this can be the culprit. Testing for this is best done by performing a voltage drop test. A voltage drop test is difficult to understand without an in person demonstration, so I won’t attempt to explain it here. But if there is paint or something else that is not metal between the starter and block, clean it off or add a large ground wire. I have had to do this every once in awhile.

If you should still need assistance with this, I recommend having an inspection for why your car isn’t starting.

Good luck!