2003 Buick Riviera timing belt

With a wrench, turn the crankshaft slowly by hand. There is a chance that there is a valve contacting a piston. If you can make two revolutions by hand, then here are some things to check. Load test the battery. Check that the battery cable connections are clean. Check for 12 volts to starter solenoid with the key in the start position. These things should be checked first then the ignition switch, neutral safety switch, starter and starter solenoid. One of these may be faulty.