My friends 97 Chevy Blazer won't start.. It turns but it won't catch.. We've tried tapping the starter, we checked the relays inside the glove box and on the fire wall. No visible damage. The battery is fine, we have a full tank. The relays in the glove box are clicking..

Can anyone help me out? Any suggestions/ideas/clues whatever would help. Also if you don't mind could you also include the location of things.

 

Is the starter turning the motor? If it is then you either have a fuel or spark problem. If it is fuel injected there should be a bleeder on the fuel bar that you could push in with a knife point while the someone is cranking the motor. if you are getting a good spray then chances are your getting fuel. to check the spark you would pull a spark plug and plug it into the wire with it out of the motor and then crank the motor. you should be able to see the arc if its not too bright out. be careful though, if your holding the plug and not the boot you will get zapped.