2000 blazer died & will not restart

I have a 2000 Chevy Blazer with a 4.3L Vortec engine that died all of a sudden with no missing or stuttering beforehand. Running just fine too with no low power problems or anything. Now the engine will not restart or even try to restart, even when carb cleaner is sprayed into the engine. Cranks over just fine, compression seems fine, no DTC codes, fuses & relays check OK, all wire connections appear OK, fuel pump works with fuel pressure a little over 60psi - installed new fuel filter because it was time and just because of this problem, getting fire at the plugs - replaced distributor cap & rotor just because there was some corrosion and because GM service bulletin #03-06-04-041A has to do with this, all the rest of the electrical system checks OK (ie no apparent keyswitch problems) & no sign of flooding as if an injector is stuck open. We even checked to make sure our OBD code reader, vehicle circuit & PCM was working as it should by purposely causing a code, the code showed just fine so we erased it. The fact that the ignition system checks OK eliminates a lot of electronic things, and the no code thing sort of eliminates still other electronic things. Fuel, fire and air under compression will run an engine, so why does this engine not run? Engine timing fault, fuel injectors inoperative, PCM problems?? Why no codes to support those things? Ideas please!
PS:This engine has internal injectors (spider) and fuel regulator (CSFI system).

did you look into whether or not the crank Position sensor is good or bad, not sure if you could check this with a volt meter or not, considering it acts like a "hall effect" sensor sending an I.R. light down at the flywheel, when the high spots (top of the teeth) reflect the light back at the sensor it relays it to the computer using this for the ignition timing. if this is bad it will not allow the engine to fire, acting as if it has no spark because the computer isn't telling it to send any. usually run about 55 smackers.

you could rule this out by taking the wire from your coil off of your distributer cap (dead center one) and laying the female side of it next to a grounded bolt or even find a way to keep it elevated from its position on the distributer cap just enough to see a spark, and watch closely while someone turns the key to crank the engine over. you should easily see a spark jump, if no spark i would try replacing the CPS (crankshaft postion sensor).

Hope this helps

Could be the distribitor cap,new parts can be bad and Vortec 350s,4.3s and 305s are known for eating distribitor caps.Aftermarket distribitor caps for these are junk,Standard is one and get an AC Delco cap instead.Another thing to check is the coil,also known for eating these and the wiring for it right at the plug in.

I have a 96 s 10 it runned and staggered but it lost power now it wont crank now they check ,compression plugs,fuel pressure,firing and everything is good .

I had a similar scenario where everything looked good but wouldn't start. The culprit turned out to be a bad (10 year old) coil wire. The internal impedence had degraded to the point where the coil was arcing from under the wire boot. This was hard to see in daylight.

But not to jump the gun too much ... Is the security light flashing per chance when the ignition is turned on. Blazers have a track record of the "passlock" security failing to recogize your key and locking out the engine for 10 minutes at a time.

The symptoms for this would be as you have stated. Plugs firing, fuel pressure etc and NO codes. The passlock stops the injectors from firing so the car will not run in the event of someone tampering with the ignition switch. Trouble is after the switch is worn it will start to fail on its own. Sometimes gradually once in a while and then the more chronic car will not start at all. I own a 1999 and use it a lot 340K KMs and have had to change mine twice.

Sounds like you have done a lot of legwork and reasoned that everything looks good. I would first look at the passlock and deal with that if it is the case. Second I would insulate the coil wire boots with di-electric grease and check for arcing there (at the coil). If there is you should see it when the engine cranks. Also make a snap when it happens... Good luck