Hello this is my first post but I've read a lot on this thing. My problem is I have a 01 Blazer 4x4 4.3 with 140k it will crank but not start if you leave the key turned over to the on position overnight all the gas in the gas tank comes out the tailpipe and floods my crankcase. I have changed every changeable part just about on the engine to no avail or no change whatsoever I am stumped as to what could be causing this problem any help greatly appreciated.

 

Could be a leak in the fuel injection spider assembly dumping raw fuel into the intake manifold instead only as a spray from the injectors into the intake ports.

Do you have any codes? When I had such a leak on my '92, I would get an error for one of the O2 sensors. Turned out, the over-rich mixture would clog it with carbon.

Here is what the fuel injector spider looks like: https://www.motormanfuelinjection.co...onversion.html

 

My guess would be the fuel pressure regulator, but the fix is still a new spider assembly.

 

 

The FPR could be the problem and can be replaced separately from the spider if money is tight, but the work is the same as a spider replacement so most will replace the entire spider as has been suggested already.

I would recommend checking the injector wiring first though to make sure that somehow there isn't one or more injector circuits permanently being pulled to ground (harness damage or malfunctioning injector driver(s) in ECM) first as that can easily be done by simply pulling the connector behind the throttle body and probing the terminals. If an injector circuit is pulled to ground, it would result in an injector sticking open, dumping fuel into the affected cylinder(s) all the time.

 

Like everyone else has said its time to pull the plenum off, i recommend reattaching the fuel lines and turning the key to RUN, not START but the position before that, with the plenum off you can easily tell if the regulator is blown because it will **** fuel over everything. if you have the money i highly recommend the 220$ or so to upgrade to MPFI injection.