95 blazer 4x4 4.3 vin W i have just replaced my spider injector with the whole kit. because my passenger side was all washed out with puddles of gas. i made sure there was no leaks before i put on the upper plenum. my fuel pressure still drops to zero when pump shuts off?? is my fuel just returning back to the tank? what would cause this? also truck is hard to start hot or cold it just seems like it cranks over way to much before it starts.

 

Two possibiliteis. The regulator isn't regulating, or the pump isn't maintaining pressure.
I made a pressure shut off that I mounted before the fuel filter. This allowed me to prime the pump, then shut off the gas supply to the filter and see if the pump would maintain pressure. If it does, you next can check the regulator by attaching a gauge to the shrader vale, prime the pump, shut the valve so pressure can't leak back thru the pump,turn the key off and watch how quickly the pressure lowers.
If the gauge goes down quickly, your regulator is shot.

My leak was in the pump assembly. The small plastic hose that runs from the pump to the top housing of the pump assembly had a pin hole in it.

If you need the pump pressure tester kit that costs about $25.00 to make, PM me, I'll give you a link to it (Capt. Hook gave me the original set-up for it)

 

so your saying that my pump may be bleeding it back off? i know the regulator is good to go.

 

Normally, the two things I mentioned are the only items that would cause pressure loss, unless the spider assembly is leaking (the third possibility I guess).

With the other things you mentioned (egr,evap), this could also indicate a bad gasket where the pump installs into the tank, or a loose vent connection on top of the tank.
Do you smell raw gas at all around the tank area?

 

no i smell no gas. i wonder if when the people replaced the fuel pump ( before i owned it )they might have messed up. i run out of gas at a 1/8th tank everytime.

 

Through trial and error, I'd say yes, you may have the wrong pump assembly in there. Also, '95 to '05 Blazers are known to have bad fuel levfel sensors. (MY '01 is rather crappy, but my '97's is pretty stable- it's the 4th pump I've had in there in less than 80k miles)

2 door and 4 door model blazers have different pump assemblies, and S10 pick-ups have another assembly. The dude at NAPA gave me an S10 pump for my 2 dr '97. Harder than all heck to get it in (too tall), but I got it. Filled the tank up, and the gauge only went to 3/4. Went back to tell NAPA, and the guy said "I gave you the wrong pump assembly". Had to redo the thing all over again. I was not happy.
The difference between the 3 vehicle/assemblies is the height of the various tanks, requiring different arms on the sensor lever. The pumps are the same, they all require the same pressure.