Chevrolet Repair: 00 Blazer will fire but not start, lock cylinder, theft deterrent

Question
I have a 2000 Blazer that was running fine one evening, 15 minutes later, tried to start, and it wouldn't. The engine will fire, but won't start. We've changed the battery, coil and wires, spark plugs, iginition module, and still nothing. We're not quite sure how, or if, to check the ignition switch and/or distributor cap. We really appreciate your help.

Answer
Hi,

 What you mean is the engine will turn over, fire up but not stay running right?  You should always check fuel pressure on a vortec no start first.  It has to be no less than 55 psi for the injectors to work at all. Or it could be a problem with PASSLOCK.  The Vehicle Theft Deterrent may be telling the ECM not to start engine management because it doesnt think there is a key in the ignition.

Possible causes:

-Defective Key
-Defective Lock Cylinder
-Relearning of Key in ignition.


 You need to determine what isnt happening first.  Whether or not you are getting fuel and spark and whether or not the injectors are pulsing.

Wayne