Starter at full power, engine wont start after rain, new fuel pump.
 

EDIT 2:
After the initial rough start described in the edit, I've had absolutely no trouble in starting the engine. I am assuming sediment from the gas tank clogged a fuel line or the fuel filter, and settled enough to allow some through later in the day. I changed the fuel filter anyway.

So now engine starts without trouble, there are no problems accelerating, nor any weird behaviors like surging or sputtering while driving. However, now when I turn the ignition to turn on the electronics, the calm whir that lasts two seconds that is the fuel pump priming the engine with fuel has turned into a limp hiss. There are no leaks on the ground, no odd smells, and as I mentioned no trouble starting the engine or driving, just a strange hissing noise instead of the typical hum when initially turning the ignition. I'd like my calm whir back. The only thing I've done to remedy this is adding a "complete fuel system cleaning formula" from AutoZone to the gas tank hoping it's just more clog that can be dissolved.

Feedback?
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EDIT:
So about 10 hours later, the engine starts, albeit very slowly. The engine kind of sputters in a way that tells me (but I might be mistaken) that fuel wasn't getting to the engine like I had mentioned might be the case. What's more, is that the audible hum that I always assumed was the fuel pump priming the engine is making an uncharacteristic hissing noise. The vehicle starts and is running, but I don't like the sound of that hiss. I have to assume it has something to do with the rain, but like I said it's rained plenty of times since the pump was installed 6 months ago and I've had absolutely no problems. Do you think the hiss might be due to a clogged line or fuel filter? I do run my gas pretty low before filling up, maybe some sediment built up?

Any input would be appreciated.

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I drive a standard trans 2WD '01 Blazer. I had the fuel pump changed about 6 months ago, I've literally had 0 problems until last night after rain (and its rained plenty of times in the 6 months since the change), where the starter cranks at full power (so not a battery issue) but fails to start the engine. If I leave the key turned, the starter revs for a good 5 seconds at full power before it skips, stops, and then starts at full power again. I put the gas to the floor to try and get some fuel into the throttle body, and during that the skip/stop happened more often at every second or so.

I haven't tested fuel or air pressure, but there is definitely plenty of fire to ignite fuel, yet it seems to me the throttle body is bone dry. The fuse to the horn is the same fuse to the fuel pump, and switched them out and the horn still works (so it wasn't the fuse). I always thought the brief, subtle hum when you turn the electronics on was the fuel pump priming the engine and that is still audible.

try acdelco cap and rotor first and maybe new wires

I made an edit. Tell me if you think the dist.cap and rotor might still be the problem.

you should probably put a fuel pressure gauge on it to see if it is within specs..In lieu of that as new guy states..if it has been awhile for a cap and rotor as well as wires-that would be good money spent-if it has been awhile or lower quality cap and rotor has been used lately...good luck..Jerry

Can you tell where the hiss is coming from? under the hood? Dampness getting under the cap can cause this issue, maybe its cracked or just old.These trucks are fussy about parts so an ac delco cap and rotor is a must

The hiss is replacing the calm whir that would sound for 2 seconds when the ignition was turned to prime the engine with fuel. It's coming from the rear end passenger side of the vehicle in the vicinity of the gas tank/fuel pump (I listened for it when I changed the fuel filter).

You need to do a leak down test to determine if its your pump