i have an 03 db z
when the car is on "on position" it shows 12 volts
and i tightened the battery terminals
it just wont start, any ideas?

 

bad battery, alternator shot, bad starter, check spark plugs, check fuses....etc.

 

More details on the problem. One common problem with "car won't start" is the cam position sensor when battery is not the culprit. Can't help with no detail condition of your car or prboblem.

 

It could be anything that Tyler350 said. Without more info , its kind of just a vague guessing game. Is the starter trying to start? Does it do nothing when you turn the ignition? If the car shows 12v, then most likely it its not a dead battery.

 

^ This. Does it turn over at all, or just a click or absolutely nothing? I can't count the number of threads like this that say "nothing happens" and then the followup is it cranks but just won't start the engine.

 

Just like above stated, and this belongs in the Tech section.

 

Won't start is different than won't turn over

 

hard to diagnose over the internet with just ur comment car wont start..does it turn over or do anything?