I have a 2001 Blazer. I drove it last on Sunday and it ran fine. Tuesday morning I tried to start it and nothing. It cranks, but sounds like the timing might be off. When i opened the hood, I found the air tube disconnected between the MAS and the filter box cover. I have been hearing a noise lately upon acceleration that sounds like the fan hitting the shroud, so I am assuming I have a bad drivers side motor mount. With that said, I can also assume that's why the air tube came apart. I don't know whether the no start is related to the air tube being disconnected or not, but I re-connected it, and still nothing. It has no trouble codes showing, but it does show 6 incomplete monitors: Catalyst, EVAP, Sec Air, O2 snsr, O2 htr, & EGR. I am currently running down the list in the sticky titled "Engine Cranks But Does Not Run". Any other advice or ideas on things to check would be much appreciated. I will be following up with questions or results, depending on my level of success, lol. Wish me luck!

 

Well it's been one week now that the Blazer is not running. I checked the distributor, cap, rotor, wires, fuel pressure, spark, and still nothing. I went out this morning and tried to start it, just for the hell of it, and it started right up! WTF?! I will have to put the scanner on it to see if it shows any DTC's now that it's running again.

 

Is your 'security' light on? Have you thought about testing the outputs from the ignition switch to see if that is energizing the proper circuits?

 

The security light is not on, and I don't know how to test the outputs from the ignition switch. I checked the DTC's and it shows a P0449 code, but it's had that code showing up and the "service engine soon" light on, long before this no start problem.
I followed the steps in your "Engine Cranks But Does Not Run" tech article. The only things I haven't checked yet is the "Fuel Injector Coil Test", the "EGR valve", or the "Ignition Control Signal Circuit", because I'm not sure how. As far as diagnostic tools, I only have an Actron Pocket scanner, a digital multi-meter, and a test light.

Just to let you know, I got out of auto mechanics in the late 80's, so I'm not very familiar with all the computer operated systems in todays vehicles, but I'm learning. Any help or direction you could give would be a huge help and greatly appreciated, thanks.