2004 Trailblazer Engine not turning over or turns over but doesn't start
 

when the car doesn't start the gauges and speedomiter go crazy. sometimes it doesn't turn over at all other time it turns over but doesn't start. i have checked the codes and found nothing showing up. so does anyone have any idea's one Mech i talked to thinks its something with the secriety system. can anyone help me here.

RE: 2004 Trailblazer Engine not turning over or turns over but doesn't start
 

Welcome to the forum!!! If it was a security device causing your problems then thereshould be a securitylight blinkingor somethingto indicate it(I think).

2002 Blazer 4.3 V - Engine turning over but not starting
 

Hi, I'm sorry if this should be a separate thread (am new to posting) but I would appreciate any suggestions you may have to offer with the above problem. It won't start in the early morning. I've tried leaving the key on for 10 minutes, as one mechanic suggested, to reset the security system. That didn't always work. I've replaced the distributor cap and button. I had a new fuel filter installed; fuel pump tested good. Yesterday I had the pass lock sensor replaced, and ended up with the same problem this morning. Usually, once I get it to start at some point in the morning, I don't have any problems starting throughout the day. Today it took several tries to get it restarted. Any ideas?
Thanks!

I had the same problem with my 00 blazer and I changed out the cap and rotor to fix it.

Fuel pump or filter

Sounds like you may have a bad ground or a short somewhere. buy a repair manual for your car there like $25 they have all the wiring diagrams inside. get a test late and start going through your harnesses if you can't find a bad ground somewhere.