Hey guys, I hava 1994 blazer 4.3 w. Was having the usual issues of rough idle, gas smell and hard starting, static pressure dropped immediately after fuel pump cycled, so pulled the plenum and sure enough the pressure line to spider was leaking. Bought a nut kit and new spider has 130,000 miles on it and i work at a parts store so i got it at cost. Put everything together which went smooth thanks to all the tips i read on here. Before i put the plenum back on i cycled the fuel pump and pressure still fell off but i could find no leaks at all. Worked my way back checking the fuel lines clear to tank and could find no leaks there either. I had to get the blazer out of the bay it was in to make room for other junk to work on (lol) so i went ahead and put plenum back on. Fired it up and runs a whole heck of a lot smoother put pressure still drops as soon as I shut the engine off. Not real sure which way to think now so any ideas anybody might have would be greatly appreciated! Thanks everbody.

 

There is a check valve in the pump. Sounds like that is not sealing off when the pump shuts off and is causing the pressure drop.

 

That was my line of thinking also. I am gonna double check again for any leaks but if I don't find any that will be my plan of attack. Thanks a million for the quick reply. Man this is an awesome forum!

 

Pull the spider tips back out of the holes in the intake. Mine was leaking out the tips and the pressure would drop off instanly. Since you are tearing it down to look again, pull the poppets back and turn the key on and see if they spray or not... Mine pissed out an ounce each in the 2 seconds the pump primes for, which made it a real bitch to start cold...

 

If the poppets are leaking do you reckon its just a bad spider?

 

If there is fuel leaking from the poppets that drops the pressure in the main feed line, then the electronic injector would also have to be leaking. The poppet nozzles should hold ~50-55psi between the nozzles (at the tip) and the electronic injector. So yeah, if you have fuel leaking from a poppet nozzle, chances are, the spider is bad. This is especially true on the CPI spiders given that there is only one electronic injector.

 

Great info thanks a million!

 

Turned out it was the check valve in the fuel pump fuel pump. Turned out i had two issues, the leaking pressure line under the plenum and the fuel pump. Got her running like a brand new one now. Thanks for the help guys. Now on to body work.