04 Blazer, went out the other day to leave, wouldn't start. It turns over and tries to start but it doesn't. It's done this before due to the security system, so I've tried all the tricks there (different key, different fob, locking unlocking doors, tried resetting passlock...) it has remote start as well, which is actually how I tried to start it the first time, and didn't. Left the battery unplugged for 24 hours, nothing. Checked for codes, fuel pressure, spark and they were both good, even tried another battery. When trying to start it will turn over fine and try to start and just act like its not getting enough gas, so it just kind of stutters. Don't know if its still the passlock or security system. Security light only flashes while door is open and only stays on for a few seconds while key is turned on. I'm at a loss and not sure what else I can do.

 

Spray some carb cleaner in the throttle body while trying to start. If it fires off using the carb cleaner, go to the sticky to do a fuel pressure/leakdown test.. I'm assuming it's currently not firing at all. The PASSLOCK system wil usaully let it run for a few seconds before it cuts the injectors off.

 

Your security light flashing when the door is open and steady on for a few seconds when the key is on then goes out means it's working correctly. As rock mentioned, the security system will let it run for a few seconds then cut off. Remote start units are famous for causing no start conditions when they fail.

 

Yes it did not run for a few seconds, just wouldn't start at all. I'm guessing its either remote start related or something else fuel related I'm not finding then. Thank you for your inputs, I will look into it further.

 

Well... tested the fuel pressure again today, only went up to 45 and then fell to 25 while trying to start. It held at 45 though, didn't go down. Still, I think I found the issue...

 

yep definent fuel issue

 

Alright had some fun today. Replaced the fuel pump and filter and before I bolted it back up I figured I'd try and start it first. Well lo and behold it didn't start. I checked to see if I had everything set up correctly (and I did) and tried to test the fuel pressure again. Well it said it was really low (30psi) or so. So I tried the tester on several other vehicles (including another blazer) and it never went past 30psi. Great, a broken tester. So I don't know if the pump was actually bad as it could have given a bad reading to begin with. Anyway my next guess would be to replace the fuel injector?

 

Doh! Well at least the fuel system will be new

 

Guessing can get expensive Get a loaner from an autoparts store and go thru the leakdown test.

 

Well I don't think its fuel related... pulled the plenum off to check the injectors and to make sure they're actually firing, they are... So the pump and injector are both good. Spark is good as well. Only thing I can think of now is if its the timing? Might just have to take it to a shop now, ugh...